JP6624243B2 - Non-aqueous electrolyte and non-aqueous electrolyte battery using the same - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte and a non-aqueous electrolyte battery using the same.

With the rapid progress of portable electronic devices such as mobile phones and notebook personal computers, demands for higher capacity of batteries used for a main power supply and a backup power supply have been increased, and nickel-cadmium batteries and nickel-cadmium batteries have been required. A non-aqueous electrolyte battery such as a lithium ion secondary battery having a higher energy density than a hydrogen battery has attracted attention.
As an electrolyte for a lithium ion secondary battery, LiPF ₆ , LiBF ₄ , LiN (CF ₃
A mixed solvent of an electrolyte such as SO ₂ ) ₂ and LiCF ₃ (CF ₂ ) ₃ SO _{3 with} a high dielectric constant solvent such as ethylene carbonate and propylene carbonate and a low viscosity solvent such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate A non-aqueous electrolyte dissolved in water is a typical example.

In addition, as a negative electrode active material of a lithium ion secondary battery, a carbonaceous material capable of occluding and releasing lithium ions is mainly used, and natural graphite, artificial graphite, amorphous carbon, and the like are exemplified. It is. Further, a metal or alloy-based negative electrode using silicon, tin, or the like for higher capacity is also known. As the positive electrode active material, a transition metal composite oxide capable of inserting and extracting lithium ions is mainly used, and typical examples of the transition metal include cobalt, nickel, manganese, and iron.

Such a lithium ion secondary battery uses a highly active positive electrode and negative electrode, and it is known that the side reaction between the electrode and the electrolyte reduces the charge / discharge capacity, improving the battery characteristics. For this purpose, various studies have been made on non-aqueous solvents and electrolytes.
Patent Literature 1 discloses an attempt to improve the storage characteristics of a battery by adding a tricarbimide compound such as triallyl cyanurate or triallyl isocyanurate to a non-aqueous electrolyte.

Patent Document 2 discloses that by dissolving a low molecular weight isocyanate compound in an organic electrolyte,
It has been reported that an excellent reaction stability can be obtained by forming a reaction layer at the electrode interface.
Patent Document 3 discloses that by using an electrolytic solution to which an organic compound having two or more nitrile groups is added, a large dipole moment due to polarization of the nitrile group causes oxidative decomposition of the electrolytic solution on the positive electrode during charging at a high voltage. It has been proposed that the battery characteristics be improved.

Patent Document 4 reports that the use of an electrolytic solution to which lithium fluorosulfonate is added improves the high-temperature storage characteristics, input / output characteristics, and impedance characteristics of a battery.
Patent Document 5 reports that the use of an electrolyte solution added with a lithium fluorophosphate salt improves the high-temperature storage characteristics of a battery.

Patent Documents 6 and 7 report that the addition of a phosphite compound and triallyl cyanurate or triallyl isocyanurate to a non-aqueous electrolyte improves cycle characteristics and safety of the electrolyte. .

Japanese Patent Application Laid-Open No. 7-192775 Japanese Patent Laid-Open No. 2000-268859 Japanese Patent Application Laid-Open No. Hei 7-176322 Japanese Patent Application Laid-Open No. 2011-187440 Japanese Patent Application Laid-Open No. 11-67270 JP 2010-282906 A International Publication WO2008 / 50599

However, the demand for improved characteristics of lithium non-aqueous electrolyte secondary batteries in recent years is increasing more and more, and all performances such as high-temperature storage characteristics, energy density, output characteristics, life, high-speed charge / discharge characteristics, and low-temperature characteristics are required. It is required to be combined at a high level, but it has not been achieved yet. There is a trade-off between durability performance such as high-temperature storage characteristics and performances such as capacity, resistance, and output characteristics, and there is a problem in that the overall performance is poorly balanced.

The present invention has been made in view of the above problems. That is, it is an object of the present invention to provide a lithium nonaqueous electrolyte secondary battery having a well-balanced overall performance in terms of performance such as durability, capacity, resistance, and output characteristics.

The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, a compound containing a structure represented by the formula (A), and (1) a nitrile compound, an isocyanate compound, a difluorophosphate, A non-aqueous electrolyte solution comprising a fluorosulfonate, lithium bis (fluorosulfonyl) imide and at least one compound selected from the group consisting of compounds represented by the following general formula (B); or 2) It has been found that the above problem can be solved by incorporating a fluorine carbonate-containing cyclic carbonate compound in an amount of 0.01 to 50.0% by weight based on the total amount of the non-aqueous electrolyte, and the present invention described below has been completed.
A non-aqueous electrolyte for a non-aqueous electrolyte battery including a positive electrode and a negative electrode capable of inserting and extracting metal ions, wherein the non-aqueous electrolyte is represented by the following general formula (A) together with an electrolyte and a non-aqueous solvent. Selected from the group consisting of compounds having a structure, and (1) a nitrile compound, an isocyanate compound, a difluorophosphate, a fluorosulfonate, a lithium bis (fluorosulfonyl) imide, and a compound represented by the following general formula (B). A non-aqueous electrolyte solution characterized by containing at least one compound as described above, or (2) a fluorine-containing cyclic carbonate compound in an amount of 0.01 to 50.0% by weight based on the total amount of the non-aqueous electrolyte solution. Non-aqueous electrolyte solution characterized by the following.

(In the formula (A), R _{1 to} R ₃ may be the same or different from each other, and have 1 to 2 carbon atoms.
It is an organic group which may have 0 substituent. )

(In the formula (B), R ₁ , R _2, and R ₃ each independently represent an alkyl group, an alkenyl group, or an alkynyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom. 0
Represents an integer of up to 6. )
In the above general formula (A), a non-aqueous electrolytic solution in which at least one of R _{1 to} R ₄ is a hydrocarbon group having a carbon-carbon unsaturated bond.

The non-aqueous electrolytic solution wherein the hydrocarbon group having an unsaturated bond is an allyl group or a methallyl group.
A non-aqueous electrolyte in which the amount of the compound having the structure represented by the general formula (A) is 0.01% by weight or more and 10.0% by weight or less based on the total amount of the non-aqueous electrolyte.
The nitrile compound, isocyanate compound, difluorophosphate, fluorosulfonate, lithium bis (fluorosulfonyl) imide and the compound represented by the following general formula (B) are used in an amount of 0.01 to 0.01% based on the total amount of the non-aqueous electrolyte. A non-aqueous electrolyte having a weight percentage of 10.0% by weight or more.

When the cyclic carbonate having a fluorine atom is monofluoroethylene carbonate,
The non-aqueous electrolyte according to any one of claims 1 to 3, wherein the non-aqueous electrolyte is at least one compound selected from the group consisting of 2,4-difluoroethylene carbonate and 4,5-difluoroethylene carbonate.
The non-aqueous electrolyte solution is at least one selected from the group consisting of cyclic carbonates having carbon-carbon unsaturated bonds, acid anhydrides, vinyl sulfonic acid esters, aromatic compounds having 12 or less carbon atoms, and chain carboxylic acid esters. Non-aqueous electrolyte solution containing the compound of the formula (1).

A non-aqueous electrolyte secondary battery comprising a positive electrode capable of storing and releasing lithium ions, a negative electrode capable of storing and releasing lithium ions, and a non-aqueous electrolyte.
A non-aqueous electrolyte battery including a carbon as a constituent element of a negative electrode active material of the negative electrode capable of inserting and extracting lithium ions.
A non-aqueous electrolyte battery having a negative electrode active material of a negative electrode capable of occluding and releasing lithium ions as a constituent element of silicon (Si) or tin (Sn).

A non-aqueous electrolyte battery in which the negative electrode active material of the negative electrode capable of occluding and releasing lithium ions is a mixture or composite of particles containing silicon (Si) or tin (Sn) as a constituent element and graphite particles.
The content of the particles containing silicon (Si) or tin (Sn) as a constituent element is 0.1 to 25% by mass based on the total of the particles containing silicon (Si) or tin (Sn) and the graphite particles. Certain non-aqueous electrolyte batteries.

ADVANTAGE OF THE INVENTION According to this invention, about a lithium non-aqueous electrolyte secondary battery, it can provide the battery with a good balance of the comprehensive performance with respect to performance, such as durability, capacity, resistance, and output characteristics.
Function / principle that the non-aqueous electrolyte secondary battery produced using the non-aqueous electrolyte of the present invention and the non-aqueous electrolyte secondary battery of the present invention become a secondary battery with a good overall performance balance Although it is not clear, it is considered as follows. However, the present invention is not limited to the operation and principle described below.

It has been reported that the compounds described in Patent Documents 1 to 5 act on the positive electrode or the negative electrode of the battery, thereby suppressing the decomposition reaction of the electrolytic solution and improving the high-temperature storage characteristics and the cycle characteristics of the battery. However, most of the effects were limited to improvement in high-temperature storage characteristics, and the effects were not sufficient. Further, the effect of improving the cycle characteristics described in Patent Document 2 was insufficient, and was not satisfactory.

Patent Document 6 discloses that a fluorinated cyclic carbonate such as fluoroethylene carbonate is used as a cyclic carbonate in an electrolytic solution, but the optimum amount and the like are not clarified.

In order to solve the above problems, the present invention provides a compound having a structure represented by the formula (A), and (1) a nitrile compound, an isocyanate compound, a difluorophosphate, a fluorosulfonate, and a lithium bis (fluorosulfonyl). ) An imide and at least one compound selected from the group consisting of compounds represented by the following general formula (B) are contained. As a result, they found that not only high-temperature storage characteristics but also cycle characteristics and rate characteristics were improved, and the present invention was completed.

In order to solve the above-mentioned problems, the present invention provides a compound having a structure represented by the formula (A) and (2)
The cyclic carbonate compound having a fluorine atom is contained in an amount of 0.01 to 5 with respect to the total amount of the nonaqueous electrolytic solution.
0.0% by weight is contained. As a result, the present inventors have found an appropriate amount of the cyclic carbonate having a fluorine atom in the non-aqueous electrolyte and have completed the present invention.

Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented without departing from the gist of the present invention.
Here, “wt%”, “wt ppm” and “parts by weight” and “mass%”, “mass pp”
“m” and “parts by mass” are synonymous with each other.
"Ppm by weight" is indicated.

1. Non-aqueous electrolyte 1-1. Non-aqueous electrolyte solution of the present invention The non-aqueous electrolyte solution of the present invention includes a compound having a structure represented by the following general formula (A), a nitrile compound, an isocyanate compound, a difluorophosphate, a fluorosulfonate, and a lithium salt. It is characterized by containing at least one compound selected from the group consisting of bis (fluorosulfonyl) imide and a compound represented by the following general formula (B).
1-1-1. Compound having a structure represented by the general formula (A)

In the formula (A), R _{1 to} R ₃ may be the same or different from each other and have 1 to 2 carbon atoms.
It is an organic group which may have 0 substituent.
Here, the organic group represents a functional group composed of atoms selected from the group consisting of a carbon atom, a hydrogen atom, a nitrogen atom, an oxygen atom, and a halogen atom. Specific examples include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, a nitrile group, an ether group, a carbonate group, and a carbonyl group.

Specific examples of the substituent include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkoxy group, a nitrile group, an ether group, a carbonate group, a carbonyl group, a carboxyl group, and a sulfonyl group which may be substituted with a halogen atom. And phosphoryl groups.
Specific examples of the alkyl group include, for example, a linear or branched chain such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, and a tert-butyl group. Examples include an alkyl group or a cyclic alkyl group such as a fluorine-substituted alkyl group, a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group.

Specific examples of the alkenyl group include a vinyl group, an allyl group, a methallyl group, a 1-propenyl group, a fluorine-substituted vinyl group, an allyl group, a methallyl group, and an alkyl group.
Specific examples of the alkynyl group include an ethynyl group, a propargyl group, and a 1-propynyl group.
Specific examples of the aryl group include a phenyl group, a tolyl group, a benzyl group, and a phenethyl group.

Specific examples of the organic group which may have a substituent include an acryl group, a methacryl group, an acryl group via an alkyl group, a methacryl group, an epoxy group, a glycidyl group, a carbonyl group, a cyanoalkyl group, a vinylsulfonyl group, Examples include a trimethylsilyl group and a trimethylsilyl group having an alkyl group.
Among them, preferably, a methyl group, an ethyl group, an i-propyl group, a tert-butyl group,
Cyclohexyl group, vinyl group, allyl group, methallyl group, ethynyl group, propargyl group, phenyl group, acryl group, methacryl group, acryl group via alkyl group, methacryl group, glycidyl group, carbonyl group, cyanoalkyl group, vinylsulfonyl Groups, a trimethylsilyl group, a trimethylsilyl group having an alkyl group, a fluorine-substituted alkyl group, a fluorine-substituted vinyl group, and an alkyl group.

More preferably, cyclohexyl group, vinyl group, allyl group, methallyl group, ethynyl group,
Propagyl group, phenyl group, acryl group, methacryl group, acryl group via alkyl group, methacryl group, glycidyl group, cyanoalkyl group, vinylsulfonyl group, trimethylsilyl group, trimethylsilyl group having alkyl group, fluorine-substituted alkyl group And a fluorine-substituted vinyl group and an alkyl group.

Particularly preferably, cyclohexyl group, vinyl group, allyl group, methallyl group, ethynyl group,
Propagyl group, acrylic group, methacryl group, acrylic group via an alkyl group, methacryl group, carbonyl group, vinylsulfonyl group, trimethylsilyl group, trimethylsilyl group having an alkyl group, fluorine-substituted vinyl group, alkyl group and the like .
Most preferably, vinyl group, allyl group, methallyl group, ethynyl group, propargyl group, acrylic group via an alkyl group, methacryl group, vinylsulfonyl group, glycidyl group, trimethylsilyl group, trimethylsilyl group having an alkyl group, fluorine-substituted And a vinyl group and an alkyl group. Among these, a group having a carbon-carbon unsaturated bond is preferable.
Specific examples of the compound include, for example,

  Among them, preferably,

More preferably,

Particularly preferably,

Most preferably,

Is mentioned.
The compounding amount of the compound of the general formula (A) with respect to the whole non-aqueous electrolyte of the present invention is not limited, and is arbitrary as long as the effect of the present invention is not significantly impaired. 0
. 001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less,
More preferably, the content is 2% by mass or less, particularly preferably 1% by mass or less, most preferably 0.5% by mass or less.
When the above range is satisfied, effects such as output characteristics, load characteristics, low-temperature characteristics, cycle characteristics, and high-temperature storage characteristics are further improved.

1-1-2. Nitrile Compound The type of the nitrile compound is not particularly limited as long as it has a nitrile group in the molecule.

Specific examples of the nitrile compound include, for example,
Acetonitrile, propionitrile, butyronitrile, isobutyronitrile, valeronitrile, isovaleronitrile, lauronitrile, 2-methylbutyronitrile, trimethylacetonitrile, hexanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, acrylonitrile, methacrylonitrile Crotononitrile, 3-methylcrotononitrile, 2-methyl-2-butenenitrile, 2-pentenenitrile, 2-methyl-2-pentenenitrile, 3-methyl-2-pentenenitrile, 2-hexenenitrile, Fluoroacetonitrile, difluoroacetonitrile, trifluoroacetonitrile,
2-fluoropropionitrile, 3-fluoropropionitrile, 2,2-difluoropropionitrile, 2,3-difluoropropionitrile, 3,3-difluoropropionitrile, 2,2,3-trifluoropropion Nitrile, 3,3,3-trifluoropropionitrile, 3,3′-oxydipropionitrile, 3,3′-thiodipropionitrile, 1,2,3-propanetricarbonitrile, 1,3,5- Compounds having one nitrile group such as pentanetricarbonitrile and pentafluoropropionitrile;
Malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimeronitrile, suberonitrile, azeranitrile, sebaconitrile, undecandinitrile, dodecandinitrile, methyl malononitrile, ethyl malononitrile, isopropyl malononitrile, tert-butyl nonylonitrile 2,2-dimethylsuccinonitrile, 2,3-dimethylsuccinonitrile, 2,3,3-trimethylsuccinonitrile, 2,2,3,3-tetramethylsuccinonitrile, 2,3-diethyl- 2,
3-dimethylsuccinonitrile, 2,2-diethyl-3,3-dimethylsuccinonitrile, bicyclohexyl-1,1-dicarbonitrile, bicyclohexyl-2,2-dicarbonitrile, bicyclohexyl-3,3 -Dicarbonitrile, 2,5-dimethyl-2,5-
Hexane dicarbonitrile, 2,3-diisobutyl-2,3-dimethylsuccinonitrile, 2,2-diisobutyl-3,3-dimethylsuccinonitrile, 2-methylglutaronitrile, 2,3-dimethylglutaronitrile , 2,4-dimethylglutaronitrile, 2,2
2,3,3-tetramethylglutaronitrile, 2,2,4,4-tetramethylglutaronitrile, 2,2,3,4-tetramethylglutaronitrile, 2,3,3,4-tetramethylglu Talonitrile, maleonitrile, fumaronitrile, 1,4-dicyanopentane, 2,
6-dicyanoheptane, 2,7-dicyanooctane, 2,8-dicyanononane, 1,6-
Dicyanodecane, 1,2-dicyanobenzene, 1,3-dicyanobenzene, 1,4-dicyanobenzene, 3,3 ′-(ethylenedioxy) dipropionitrile, 3,3 ′-(ethylenedithio) dipropio Nitrile, 3,9-bis (2-cyanoethyl) -2,4,8,1
A compound having two nitrile groups such as 0-tetraoxaspiro [5,5] undecane;
Compounds having three cyano groups such as cyclohexanetricarbonitrile, triscyanoethylamine, triscyanoethoxypropane, tricyanoethylene, pentanetricarbonitrile, propanetricarbonitrile and heptanetricarbonitrile;
And the like.

Of these, lauronitrile, crotononitrile, succinonitrile, glutaronitrile, adiponitrile, pimeronitrile, suberonitrile, azeranitrile, sebaconitrile, undecandinitrile, dodecandinitrile, fumaronitrile, 3,9-bis (2
-Cyanoethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane is preferred from the viewpoint of improving storage characteristics. In addition, succinonitrile, glutaronitrile, adiponitrile, pimeronitrile, suberonitrile, azeranitrile, sebaconitrile, undecandinitrile, dodecandinitrile, fumalonitrile, 3,9-bis (2-cyanoethyl)-
Dinitrile compounds such as 2,4,8,10-tetraoxaspiro [5,5] undecane are particularly preferred. Further, a chain dinitrile having 4 or more carbon atoms is preferable.

As the nitrile compound, one kind may be used alone, and two kinds or more may be used in optional combination and ratio. The amount of the nitrile compound to be added to the whole non-aqueous electrolyte of the present invention is not limited, and is arbitrary as long as the effect of the present invention is not significantly impaired. Or more, preferably 0.01% by mass or more, more preferably 0.1% by mass.
It is contained at a concentration of at least 10% by mass, usually at most 10% by mass, preferably at most 5% by mass, more preferably at most 3% by mass, further preferably at most 2% by mass, most preferably at most 1% by mass. When the above range is satisfied, effects such as output characteristics, load characteristics, low-temperature characteristics, cycle characteristics, and high-temperature storage characteristics are further improved.

1-1-4. Isocyanate Compound The type of the isocyanate compound is not particularly limited as long as the compound has an isocyanate group in the molecule.
Specific examples of the isocyanate compound include, for example,
Hydrocarbon monoisocyanate compounds such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropyl isocyanate, butyl isocyanate, tert-butyl isocyanate, pentyl isocyanate, hexyl isocyanate, cyclohexyl isocyanate, phenyl isocyanate, and fluorophenyl isocyanate;

Monoisocyanate compounds having a carbon-carbon unsaturated bond, such as vinyl isocyanate, allyl isocyanate, ethynyl isocyanate, and propynyl isocyanate;
Monomethylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 1,3-diisocyanate Natopropane, 1,4-diisocyanato-2
-Butene, 1,4-diisocyanato-2-fluorobutane, 1,4-diisocyanato-2
1,3-difluorobutane, 1,5-diisocyanato-2-pentene, 1,5-diisocyanato-2-methylpentane, 1,6-diisocyanato-2-hexene, 1,6-diisocyanato-3-hexene, 1,6 -Diisocyanato-3-fluorohexane, 1,6-diisocyanato-3,4-difluorohexane, toluene diisocyanate, xylene diisocyanate, tolylene diisocyanate, 1,2-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanate (Natomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, dicyclohexylmethane-1,1 '-Diisocyane DOO, dicyclohexylmethane-2,2'-diisocyanate, dicyclohexylmethane-3,3'-diisocyanate, dicyclohexylmethane -
4,4′-diisocyanate, bicyclo [2.2.1] heptane-2,5-diylbis (
Methyl isocyanate), bicyclo [2.2.1] heptane-2,6-diylbis (methyl isocyanate), isophorone diisocyanate, carbonyl diisocyanate, 1,4
-Diisocyanatobutane-1,4-dione, 1,5-diisocyanatopentane-1,5-
Hydrocarbon diisocyanate compounds such as dione, 2,2,4-trimethylhexamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate;
Isocyanate compounds such as diisocyanatosulfone, (ortho-, meta-, para-) toluenesulfonyl isocyanate, benzenesulfonylisocyanate, fluorosulfonyl isocyanate, phenoxysulfonyl isocyanate, pentafluorophenoxysulfonyl isocyanate, methoxysulfonyl isocyanate;
And the like.

Among them, monoisocyanate compounds having a carbon-carbon unsaturated bond such as vinyl isocyanate, allyl isocyanate, ethynyl isocyanate, and propynyl isocyanate;
Monomethylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 1,3-bis ( Isocyanatomethyl) cyclohexane, dicyclohexylmethane-4,4′-diisocyanate, bicyclo [2.2.1] heptane-2,
5-diylbis (methyl isocyanate), bicyclo [2.2.1] heptane-2,6-
Hydrocarbon diisocyanate compounds such as diylbis (methyl isocyanate), isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate;
Isocyanate compounds such as diisocyanatosulfone, (ortho-, meta-, para-) toluenesulfonyl isocyanate, benzenesulfonylisocyanate, fluorosulfonyl isocyanate, phenoxysulfonyl isocyanate, pentafluorophenoxysulfonyl isocyanate, methoxysulfonyl isocyanate;
Is preferred from the viewpoint of improving cycle characteristics and storage characteristics.

More preferably, allyl isocyanate, hexamethylene diisocyanate, 1,3
-Bis (isocyanatomethyl) cyclohexane, diisocyanatosulfone, (ortho-,
Meta-, para-) toluenesulfonyl isocyanate is preferred, and hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, (
Ortho-, meta-, para-) toluenesulfonyl isocyanate is preferred, most preferably hexamethylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane.

Further, as the isocyanate compound, an isocyanate compound having a branched chain is preferable.
The isocyanate compound used in the present invention may be a trimer compound derived from a compound having at least two isocyanate groups in a molecule, or an aliphatic polyisocyanate obtained by adding a polyhydric alcohol thereto. For example, the following general formulas (3-1) to (3)
And bifunctional modified polyisocyanates of the following general formulas (1-2-1) to (1-2).
In 4), R and R ′ are each independently any hydrocarbon group).

The compound having at least two isocyanate groups in the molecule used in the present invention also includes a so-called blocked isocyanate which has been improved in storage stability by being blocked with a blocking agent. Examples of the blocking agent include alcohols, phenols, organic amines, oximes, and lactams. Specifically, n-butanol, phenol, tributylamine, diethylethanolamine, methylethylketoxime, ε-caprolactam And the like.

In order to promote a reaction based on a compound having at least two isocyanate groups in the molecule and to obtain a higher effect, a metal catalyst such as dibutyltin dilaurate or the like, 1,8-diazabicyclo [5.4.0] undecene- It is also preferable to use an amine catalyst such as 7 in combination.
Further, as the compound having an isocyanate group, one kind may be used alone, and two kinds or more may be used in optional combination and ratio.

The compounding amount of the compound having an isocyanate group with respect to the whole non-aqueous electrolyte of the present invention is not limited, and is arbitrary as long as the effect of the present invention is not significantly impaired. 001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more.
% By mass or more, usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, particularly preferably 1% by mass or less, and most preferably 0.5% by mass or less. % Or less.

When the above range is satisfied, effects such as output characteristics, load characteristics, low-temperature characteristics, cycle characteristics, and high-temperature storage characteristics are further improved.
1-1-4. Difluorophosphate The counter cation of difluorophosphate is not particularly limited, but lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, and NR11R12R13R14 (wherein, R11 to R14 are each independently , A hydrogen atom or an organic group having 1 to 12 carbon atoms).

The organic group having 1 to 12 carbon atoms represented by R11 to R14 of the above ammonium is not particularly limited. Preferred examples include a cycloalkyl group, an aryl group which may be substituted with a halogen atom or an alkyl group, and a nitrogen atom-containing heterocyclic group which may have a substituent. Among them, R11 to R14 each independently represent a hydrogen atom, an alkyl group,
A cycloalkyl group or a nitrogen-containing heterocyclic group is preferred.

As specific examples of difluorophosphate,
Examples thereof include lithium difluorophosphate, sodium difluorophosphate, and potassium difluorophosphate, with lithium difluorophosphate being preferred.
One type of difluorophosphate may be used alone, or two or more types may be used in combination in any combination and in any ratio. The amount of the difluorophosphate is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired.

The amount of the difluorophosphate is usually 0.001% by mass in 100% by mass of the non-aqueous electrolyte.
Or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 1% by mass or more.
The content is 0% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, and most preferably 1% by mass or less.
Within this range, the non-aqueous electrolyte battery can easily exhibit a sufficient effect of improving the cycle characteristics, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity retention rate is reduced. Easy to avoid.

1-1-5. Fluorosulfonate The counter cation of the fluorosulfonate is not particularly limited, but lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, and NR11R12R13R14 (wherein, R11 to R14 are each independently , A hydrogen atom or an organic group having 1 to 12 carbon atoms).

The organic group having 1 to 12 carbon atoms represented by R11 to R14 of the above ammonium is not particularly limited. Preferred examples include a cycloalkyl group, an aryl group which may be substituted with a halogen atom or an alkyl group, and a nitrogen atom-containing heterocyclic group which may have a substituent. Among them, R11 to R14 each independently represent a hydrogen atom, an alkyl group,
A cycloalkyl group or a nitrogen-containing heterocyclic group is preferred.

Specific examples of the fluorosulfonic acid salt include:
Examples include lithium fluorosulfonate, sodium fluorosulfonate, potassium fluorosulfonate, rubidium fluorosulfonate, and cesium fluorosulfonate, with lithium fluorosulfonate being preferred.
One type of fluorosulfonic acid salt may be used alone, or two or more types may be used in combination in any combination and in any ratio. The amount of the fluorosulfonate is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired.

The amount of the monofluorosulfonate is usually 0.001 in 100% by mass of the non-aqueous electrolyte.
Mass% or more, preferably 0.01 mass% or more, more preferably 0.1 mass% or more,
The content is usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, and most preferably 1% by mass or less.
Within this range, the non-aqueous electrolyte battery can easily exhibit a sufficient effect of improving the cycle characteristics, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity retention rate is reduced. Easy to avoid.
1-1-7. Lithium bis (fluorosulfonyl) imide The structural formula is represented by the following formula (c).

The compounding amount of lithium bis (fluorosulfonyl) imide is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, in 100% by mass of the nonaqueous electrolyte. The content is usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, and most preferably 1% by mass or less.
Within this range, the non-aqueous electrolyte battery can easily exhibit a sufficient effect of improving the cycle characteristics, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity retention rate is reduced. Easy to avoid.
1-1-8. Compound having a structure represented by the general formula (B)

In the formula (B), R ₁ , R ₂ and R ₃ each independently represent an alkyl group, an alkenyl group or an alkynyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom, and n is 0
Represents an integer of up to 6.
Examples of the compound represented by the general formula (B) include the following compounds.

<Compound of general formula (B) wherein n = 0>
Trimethyl phosphonoformate, methyl diethyl phosphonoformate, methyl dipropyl phosphonoformate, methyl dibutyl phosphonoformate, triethyl phosphonoformate, ethyl dimethyl phosphonoformate, ethyl dipropyl phosphonoformate, ethyl Dibutyl phosphonoformate, tripropyl phosphonoformate, propyl dimethyl phosphonoformate, propyl diethyl phosphonoformate, propyl dibutyl phosphonoformate, tributyl phosphonoformate, butyl dimethyl phosphonoformate, butyl diethyl phosphonoformate Noformate, butyl dipropylphosphonoformate, methyl bis (2,2,2-trifluoroethyl) phosphonoformate, ethyl bis (2 2,2-trifluoroethyl) phosphonoacetate formate, propyl bis (2,2,2-trifluoroethyl) phosphonoacetate formate, butyl bis (2,2,2-trifluoroethyl) phosphonoacetate formate and the like.

<Compound of Formula (B) wherein n = 1>
Trimethyl phosphonoacetate, Methyl diethyl phosphonoacetate, Methyl dipropyl phosphonoacetate, Methyl dibutyl phosphonoacetate, Triethyl phosphonoacetate, Ethyl dimethyl phosphonoacetate, Ethyl dipropyl phosphonoacetate, Ethyl dibutyl phosphonoacetate, Tripropyl Phosphonoacetate,
Propyl dimethyl phosphonoacetate, propyl diethyl phosphonoacetate, propyl dibutyl phosphonoacetate, tributyl phosphonoacetate, butyl dimethyl phosphonoacetate, butyl diethyl phosphonoacetate, butyl dipropyl phosphonoacetate, methyl bis (2,2,2 -Trifluoroethyl) phosphonoacetate, ethyl bis (2,2,2-trifluoroethyl) phosphonoacetate, propyl bis (2,2,2-trifluoroethyl) phosphonoacetate, butyl bis (2,2 2
-Trifluoroethyl) phosphonoacetate, allyl dimethylphosphonoacetate, allyl diethylphosphonoacetate, 2-propynyl dimethylphosphonoacetate, 2
-Propynyl diethylphosphonoacetate and the like.

<Compound of Formula (B) wherein n = 2>
Trimethyl 3-phosphonopropionate, methyl 3- (diethylphosphono) propionate, methyl 3- (dipropylphosphono) propionate, methyl 3- (dibutylphosphono) propionate, triethyl 3-phosphonopropionate, ethyl 3-
(Dimethylphosphono) propionate, ethyl 3- (dipropylphosphono) propionate, ethyl 3- (dibutylphosphono) propionate, tripropyl-3-phosphonopropionate, propyl 3- (dimethylphosphono) propionate, propyl3 −
(Diethylphosphono) propionate, propyl 3- (dibutylphosphono) propionate, tributyl3-phosphonopropionate, butyl 3- (dimethylphosphono) propionate, butyl 3- (diethylphosphono) propionate, butyl 3- ( Dipropylphosphono) propionate, methyl 3- (bis (2,2,2-trifluoroethyl) phosphono) propionate, ethyl 3- (bis (2,2,2-trifluoroethyl) phosphono) propionate, propyl 3- (Bis (2,2,2-trifluoroethyl) phosphono) propionate, butyl 3- (bis (2,2,2-trifluoroethyl)
Phosphono) propionate and the like.

<Compound of Formula (B) wherein n = 3>
Trimethyl 4-phosphonobutyrate, methyl 4- (diethylphosphono) butyrate, methyl 4- (dipropylphosphono) butyrate, methyl 4- (dibutylphosphono)
Butyrate, triethyl 4-phosphonobutyrate, ethyl 4- (dimethylphosphono)
Butyrate, ethyl 4- (dipropylphosphono) butyrate, ethyl 4- (dibutylphosphono) butyrate, tripropyl 4-phosphonobutyrate, propyl 4- (dimethylphosphono) butyrate, propyl 4- (diethylphosphono) Butyrate, propyl 4- (dibutylphosphono) butyrate, tributyl 4-phosphonobutyrate, butyl 4- (dimethylphosphono) butyrate, butyl 4- (diethylphosphono) butyrate, butyl 4- (dipropylphosphono) butyrate etc.

Of these, compounds with n = 0, 1, 2 are preferred from the viewpoint of improving battery characteristics, and n = 0,
One compound is particularly preferred, and a compound where n = 1 is most preferred.
Among the compounds in which n = 1, a compound in which R1 to R3 are a saturated hydrocarbon group is preferable.
1-1-9. Cyclic carbonate having a fluorine atom Examples of the cyclic carbonate compound having a fluorine atom include a fluorinated product of a cyclic carbonate having an alkylene group having 2 to 6 carbon atoms, and a derivative thereof.For example, a fluorinated product of ethylene carbonate, and a derivative thereof Is mentioned. Examples of the derivative of the fluorinated ethylene carbonate include a fluorinated ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms). Among them, ethylene carbonate having 1 to 8 fluorine atoms and derivatives thereof are preferable.

In particular,
Monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,
5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,5-difluoro-4-methylethylene carbonate, 4-fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4- (fluoromethyl) -ethylene carbonate, 4- (difluoromethyl) -ethylene carbonate, 4- (trifluoromethyl) -ethylene carbonate, 4- (fluoromethyl)-
4-fluoroethylene carbonate, 4- (fluoromethyl) -5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4,5-difluoro-4,5-dimethylethylene carbonate, 4,4-difluoro -5,5-dimethylethylene carbonate and the like.

Above all, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate and 4,5-difluoroethylene carbonate gives high ionic conductivity and suitably forms an interface protective film. Is more preferable.
As the cyclic carbonate compound having a fluorine atom, one kind may be used alone, or two or more kinds may be used in optional combination and ratio.

As the cyclic carbonate compound having a fluorine atom, one kind may be used alone, or two or more kinds may be used in optional combination and ratio. The amount of the halogenated cyclic carbonate to be added to the entire nonaqueous electrolyte of the present invention is not limited, and is not limited as long as the effect of the present invention is not significantly impaired. % Or more, preferably 0.1% by weight.
05% by weight or more, more preferably 0.1% by weight or more, and usually 50% by weight or less, preferably 30% by weight or less, more preferably 20% by weight or less, particularly preferably 10% by weight or less,
Most preferably, it is contained at a concentration of 5% by weight or less.

1-2. Electrolyte <Lithium salt>
As the electrolyte, a lithium salt is usually used. The lithium salt is not particularly limited as long as it is known to be used for this purpose, and any lithium salt can be used.
Specifically, the following are mentioned.

For _{example, LiPF 6, LiBF 4, LiClO} 4, LiAlF 4, LiSbF 6, Li
Inorganic lithium salts such as TaF ₆ and LiWF ₇ ;
Lithium tungstates such as LiWOF ₅ ;
HCO ₂ Li, CH ₃ CO ₂ Li, CH ₂ FCO ₂ Li, CHF ₂ CO ₂ Li, CF ₃
CO ₂ Li, CF ₃ CH ₂ CO ₂ Li, CF ₃ CF ₂ CO ₂ Li, CF ₃ CF ₂ CF ₂ C
Lithium carboxylate salts such as O ₂ Li, CF ₃ CF ₂ CF ₂ CF ₂ CO ₂ Li;
FSO ₃ Li, CH ₃ SO ₃ Li, CH ₂ FSO ₃ Li, CHF ₂ SO ₃ Li, CF ₃
SO ₃ Li, CF ₃ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ SO ₃ Li, CF ₃ CF ₂ C
Lithium sulfonates such as F ₂ CF ₂ SO ₃ Li;
LiN (FCO) ₂ , LiN (FCO) (FSO ₂ ), LiN (FSO ₂ ) ₂ , LiN
(FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ )
₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3
- perfluoropropane _{disulfonylimide, LiN (CF 3 SO 2)} (C 4 F 9 SO 2
) And other lithium imide salts;
Lithium methide salts such as LiC (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ and LiC (C ₂ F ₅ SO ₂ ) ₃ ;

Lithium oxalatoborate salts such as lithium difluorooxalatoborate and lithium bis (oxalato) borate;
Lithium oxalatophosphate salts such as lithium tetrafluorooxalatophosphate, lithium difluorobis (oxalato) phosphate, lithium tris (oxalato) phosphate;
In addition, LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅ ) ₂ , LiPF ₄ (CF ₃ S
O ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ ,
LiBF ₃ C ₃ F ₇ , LiBF ₂ (CF ₃ ) _2, LiBF ₂ (C ₂ F ₅ ) ₂ , LiBF ₂
Fluorinated organic lithium salts such as (CF ₃ SO ₂ ) ₂ and LiBF ₂ (C ₂ F ₅ SO ₂ ) 2;
And the like.

Among them, LiPF ₆ , LiBF ₄ , LiSbF ₆ , LiTaF ₆ , FSO ₃ Li, CF
₃ SO ₃ Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (
_{CF 3 SO 2) 2, LiN} (C 2 F 5 SO 2) 2, lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide, LiC _{(FSO 2) 3} , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ ,
Lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, lithium difluorobisoxalatophosphate, LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ ( C
₂ F _{5) 3} or the like is output characteristics and high-rate discharge characteristics, high-temperature storage characteristics, particularly preferred from the viewpoint that an effect of improving the cycle characteristics and the like.

These lithium salts may be used alone or in combination of two or more. Preferred examples of the case where two or more kinds are used in combination are LiPF ₆ and LiBF ₄ , and LiPF ₆ and LiN (FSO ₂ ) ₂
Alternatively, a combination of LiPF ₆ and FSO ₃ Li or the like has an effect of improving load characteristics and cycle characteristics.
In this case, the concentration of LiBF ₄ or FSO ₃ Li with respect to 100% by mass of the whole nonaqueous electrolyte is not limited in terms of the blending amount, and is arbitrary as long as the effects of the present invention are not significantly impaired. On the other hand, it is usually at least 0.01% by mass, preferably at least 0.1% by mass, and usually at most 30% by mass, preferably at most 20% by mass.

Another example is the combined use of an inorganic lithium salt and an organic lithium salt, and the combined use of both has an effect of suppressing deterioration due to high-temperature storage. As the organic lithium salt, CF ₃ SO ₃
Li, LiN (FSO ₂ ) ₂ , LiN (FSO ₂ ) (CF ₃ SO ₂ ), LiN (CF ₃ S
O ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide, Li
C (FSO ₂ ) ₃ , LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , lithium bisoxalatoborate, lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, lithium difluorobisoxa Latophosphate, Li
_{BF 3 CF 3, LiBF 3 C2F} 5, LiPF 3 (CF 3) 3, LiPF 3 (C 2 F 5)
_It is preferably ₃ or the like. In this case, the ratio of the organic lithium salt to 100% by mass of the entire nonaqueous electrolyte is preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, and preferably 30% by mass or less. And particularly preferably 20% by mass or less.

The concentration of these lithium salts in the non-aqueous electrolyte is not particularly limited as long as the effects of the present invention are not impaired, but the electric conductivity of the electrolyte is kept in a good range, and good battery performance is secured. Therefore, the total molar concentration of lithium in the non-aqueous electrolyte is preferably 0.3 mol /
L or more, more preferably 0.4 mol / L or more, still more preferably 0.5 mol / L or more, and preferably 3 mol / L or less, more preferably 2.5 mol / L or less, and still more preferably 2.0 mol / L or less. / L or less.
When the total molar concentration of lithium is within the above range, the electric conductivity of the electrolytic solution is sufficient, and a decrease in electric conductivity due to an increase in viscosity and a decrease in battery performance due to the decrease are prevented.

1-3. Non-aqueous solvent The non-aqueous solvent in the present invention is not particularly limited, and a known organic solvent can be used. Examples thereof include a cyclic carbonate having no fluorine atom, a chain carbonate, a cyclic and chain carboxylic acid ester, an ether compound, and a sulfone compound.

<Cyclic carbonate without fluorine atom>
Examples of the cyclic carbonate having no fluorine atom include a cyclic carbonate having an alkylene group having 2 to 4 carbon atoms.
Specific examples of the cyclic carbonate having no fluorine atom and having an alkylene group having 2 to 4 carbon atoms include ethylene carbonate, propylene carbonate, and butylene carbonate. Among them, ethylene carbonate and propylene carbonate are particularly preferable from the viewpoint of improving battery characteristics derived from the improvement of the degree of dissociation of lithium ions.

As the cyclic carbonate having no fluorine atom, one kind may be used alone, and two kinds or more may be used in optional combination and ratio.
The compounding amount of the cyclic carbonate having no fluorine atom is not particularly limited, and is arbitrary as long as the effect of the present invention is not significantly impaired.
In 0 volume%, it is 5 volume% or more, more preferably 10 volume% or more. By setting it in this range, it is possible to avoid a decrease in electric conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte, and to provide a large current discharge characteristic, stability to the negative electrode, and cycle characteristics of the non-aqueous electrolyte battery in a favorable range. It becomes easier.
Further, it is 95% by volume or less, more preferably 90% by volume or less, further preferably 85% by volume or less. By setting the content in this range, the viscosity of the non-aqueous electrolyte is adjusted to an appropriate range, and a decrease in ionic conductivity is suppressed, and the load characteristics of the non-aqueous electrolyte battery can be easily adjusted to a favorable range.

<Chain carbonate>
As the chain carbonate, a chain carbonate having 3 to 7 carbon atoms is preferable, and a chain carbonate having 3 to 7 carbon atoms is preferable.
7 dialkyl carbonates are more preferred.
Specific examples of the chain carbonate include dimethyl carbonate, diethyl carbonate,
Di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, n-
Butyl methyl carbonate, isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t-butyl ethyl carbonate, and the like.

Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate are preferred, and dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate are particularly preferred. is there.
Further, chain carbonates having a fluorine atom (hereinafter referred to as “fluorinated chain carbonate”)
May be described).

The number of fluorine atoms in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or to different carbons.
As the fluorinated chain carbonate, fluorinated dimethyl carbonate and its derivatives,
Examples include fluorinated ethyl methyl carbonate and its derivatives, fluorinated diethyl carbonate and its derivatives, and the like.

Examples of the fluorinated dimethyl carbonate and its derivatives include fluoromethyl methyl carbonate, difluoromethyl methyl carbonate, trifluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, bis (difluoro) methyl carbonate, bis (trifluoromethyl) carbonate and the like. Can be
Examples of fluorinated ethyl methyl carbonate and its derivatives include 2-fluoroethyl methyl carbonate, ethyl fluoromethyl carbonate, 2,2-difluoroethyl methyl carbonate, 2-fluoroethyl fluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2 -Trifluoroethyl methyl carbonate, 2,2-difluoroethyl fluoromethyl carbonate, 2-fluoroethyl difluoromethyl carbonate, ethyl trifluoromethyl carbonate and the like.

Examples of the fluorinated diethyl carbonate and derivatives thereof include ethyl- (2-fluoroethyl) carbonate, ethyl- (2,2-difluoroethyl) carbonate, bis (2-fluoroethyl) carbonate, and ethyl- (2,2,2- Trifluoroethyl) carbonate, 2,2-difluoroethyl-2′-fluoroethyl carbonate, bis (2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2′-fluoroethyl carbonate, 2, 2,2-trifluoroethyl-2 ′, 2′-difluoroethyl carbonate, bis (2,2,2-trifluoroethyl) carbonate and the like can be mentioned.

One type of chain carbonate may be used alone, or two or more types may be used in combination in any combination and in any ratio.
The mixing amount of the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, and further preferably 15% by volume or more in 100% by volume of the nonaqueous solvent. By setting the lower limit in this manner, the viscosity of the non-aqueous electrolyte is set to an appropriate range, the decrease in ionic conductivity is suppressed, and the large current discharge characteristics of the non-aqueous electrolyte battery can be easily set to a favorable range. Also,
The chain carbonate is preferably 90% by volume or less, more preferably 85% by volume or less, and particularly preferably 80% by volume or less, in 100% by volume of the nonaqueous solvent. By setting the upper limit in this way, it is possible to avoid a decrease in electric conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte, and to easily set the large current discharge characteristics of the non-aqueous electrolyte battery to a favorable range.

<Cyclic carboxylate>
As the cyclic carboxylic acid ester, those having 3 to 12 carbon atoms are preferable.
Specifically, gamma butyrolactone, gamma valerolactone, gamma caprolactone,
Epsilon caprolactone and the like. Among them, gamma-butyrolactone is particularly preferable from the viewpoint of improving the battery characteristics derived from the improvement of the degree of dissociation of lithium ions.

As the cyclic carboxylic acid ester, one type may be used alone, or two or more types may be used in optional combination and ratio.
The compounding amount of the cyclic carboxylic acid ester is usually preferably 5% by volume or more, more preferably 10% by volume or more in 100% by volume of the nonaqueous solvent. Within this range, the electrical conductivity of the non-aqueous electrolyte solution is improved, and the large current discharge characteristics of the non-aqueous electrolyte battery are easily improved. The amount of the cyclic carboxylic acid ester is preferably 50% by volume or less, more preferably 40% by volume or less. By setting the upper limit in this manner, the viscosity of the non-aqueous electrolyte is set to an appropriate range, a decrease in electric conductivity is avoided, an increase in negative electrode resistance is suppressed, and a large current discharge of the non-aqueous electrolyte secondary battery is performed. The characteristics can be easily set in a good range.

<Ether compounds>
As the ether-based compound, carbon atoms having a carbon number of 3 to which a part of hydrogen may be substituted by fluorine may be used.
A chain ether having 10 and a cyclic ether having 3 to 6 carbon atoms are preferred.
As a chain ether having 3 to 10 carbon atoms,
Diethyl ether, di (2-fluoroethyl) ether, di (2,2-difluoroethyl) ether, di (2,2,2-trifluoroethyl) ether, ethyl (2-fluoroethyl) ether, ethyl (2 2,2-trifluoroethyl) ether, ethyl (1,
1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2-
(Trifluoroethyl) ether, (2-fluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, (2,2,2-trifluoroethyl) (1,1,2,2-tetrafluoroethyl) ) Ether, ethyl-n-propyl ether, ethyl (3-fluoro-n
-Propyl) ether, ethyl (3,3,3-trifluoro-n-propyl) ether,
Ethyl (2,2,3,3-tetrafluoro-n-propyl) ether, ethyl (2,2,3
3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n-propyl ether, (2-fluoroethyl) (3-fluoro-n-propyl) ether, (2
-Fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2
, 2-trifluoroethyl-n-propyl ether, (2,2,2-trifluoroethyl) (3-fluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (3
, 3,3-trifluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,2- Trifluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 1,
1,2,2-tetrafluoroethyl-n-propyl ether, (1,1,2,2-tetrafluoroethyl) (3-fluoro-n-propyl) ether, (1,1,2,2-tetrafluoro Ethyl) (3,3,3-trifluoro-n-propyl) ether, (1,1,2
, 2-Tetrafluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,3,3-pentane Fluoro-n-propyl) ether, di-n-propylether, (n-propyl) (3-fluoro-n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) Ether, (n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (n-propyl) (2,2,3,3,3-pentafluoro-n-propyl)
Ether, di (3-fluoro-n-propyl) ether, (3-fluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2 , 2,3,3-tetrafluoro-n-propyl) ether, (3-fluoro-n
-Propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3
, 3,3-trifluoro-n-propyl) ether, (3,3,3-trifluoro-n-
Propyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (3,3,3
-Trifluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (2,2,3,3-tetrafluoro-n-propyl) ether, (2 2
, 3,3-tetrafluoro-n-propyl) (2,2,3,3,3-pentafluoro-n
-Propyl) ether, di (2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-butylether, dimethoxymethane, methoxyethoxymethane, methoxy (2-fluoroethoxy) methane, methoxy ( 2,2,2-trifluoroethoxy) methane Methoxy (1,1,2,2-tetrafluoroethoxy) methane, diethoxymethane, ethoxy (2-fluoroethoxy) methane, ethoxy (2,2,2-trifluoro) Ethoxy) methane, ethoxy (1,1,2,2-tetrafluoroethoxy) methane, di (2-fluoroethoxy) methane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) methane, (2 -Fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methanedi (2,2,2-trifluoro) (Roethoxy) methane, (2,2,2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methane, di (1,1,2,2-tetrafluoroethoxy) methane, dimethoxyethane, methoxy Ethoxyethane, methoxy (2
-Fluoroethoxy) ethane, methoxy (2,2,2-trifluoroethoxy) ethane,
Methoxy (1,1,2,2-tetrafluoroethoxy) ethane, diethoxyethane, ethoxy (2-fluoroethoxy) ethane, ethoxy (2,2,2-trifluoroethoxy)
Ethane, ethoxy (1,1,2,2-tetrafluoroethoxy) ethane, di (2-fluoroethoxy) ethane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy)
Ethane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (2,2,2-trifluoroethoxy) ethane, (2,2,2-trifluoroethoxy) (1 , 1,2,2-tetrafluoroethoxy) ethane, di (1,1,2,2-tetrafluoroethoxy) ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether and the like. No.

Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, , 4-dioxane and the like, and fluorinated compounds thereof.
Among them, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether have a high solvating ability to lithium ions and improve ion dissociation. From the viewpoint of low viscosity and high ionic conductivity, dimethoxymethane, diethoxymethane and ethoxymethoxymethane are particularly preferable.

One of the ether compounds may be used alone, or two or more thereof may be used in any combination and in any ratio.
The compounding amount of the ether compound is usually 5% by volume or more, more preferably 10% by volume or more, still more preferably 15% by volume or more, and preferably 70% by volume or less in 100% by volume of the nonaqueous solvent. It is more preferably at most 60% by volume, further preferably at most 50% by volume.

Within this range, it is easy to secure the effect of improving the lithium ion dissociation degree of the chain ether and the ion conductivity derived from the decrease in viscosity. It is easy to avoid a situation where the capacity is reduced due to the co-insertion.
<Sulfone compound>
As the sulfone compound, a cyclic sulfone having 3 to 6 carbon atoms and a chain sulfone having 2 to 6 carbon atoms are preferable. The number of sulfonyl groups in one molecule is preferably one or two.

As the cyclic sulfone having 3 to 6 carbon atoms,
Trimethylene sulfones, tetramethylene sulfones, hexamethylene sulfones, which are monosulfone compounds;
Examples of the disulfone compound include trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones.

Among them, from the viewpoints of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.
As the sulfolane, sulfolane and / or a sulfolane derivative (hereinafter sometimes referred to as “sulfolane” including sulfolane) is preferable. As the sulfolane derivative, one in which one or more hydrogen atoms bonded to carbon atoms constituting the sulfolane ring are substituted with a fluorine atom or an alkyl group is preferable.

Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3
-Fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorosulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2- Fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-
Fluoro-3-methylsulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethyl Sulfolane, 3-difluoromethylsulfolane, 2-trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3
-(Trifluoromethyl) sulfolane, 4-fluoro-3- (trifluoromethyl) sulfolane, 5-fluoro-3- (trifluoromethyl) sulfolane, and the like are preferable in terms of high ionic conductivity and high input / output characteristics. .

Further, as a chain sulfone having 2 to 6 carbon atoms,
Dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, n-propyl ethyl sulfone, di-n-propyl sulfone, isopropyl methyl sulfone, isopropyl ethyl sulfone, diisopropyl sulfone, n-butyl methyl sulfone, n-butyl ethyl Sulfone, t-butyl methyl sulfone, t-butyl ethyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoro Ethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, perfume Oro ethyl methyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoroethyl sulfone, di (trifluoroethyl) sulfone,
Perfluorodiethylsulfone, fluoromethyl-n-propylsulfone, difluoromethyl-n-propylsulfone, trifluoromethyl-n-propylsulfone, fluoromethylisopropylsulfone, difluoromethylisopropylsulfone, trifluoromethylisopropylsulfone, trifluoroethyl- n-propylsulfone, trifluoroethylisopropylsulfone, pentafluoroethyl-n-propylsulfone, pentafluoroethylisopropylsulfone, trifluoroethyl-n-butylsulfone, trifluoroethyl-t-butylsulfone, pentafluoroethyl-n- Butylsulfone, pentafluoroethyl-t-butylsulfone, and the like.

Among them, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone , Monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl pentafluoro Ethyl sulfone, trifluoromethyl-n-propyl sulfone, trifluoromethyl isopropyl sulfone, tri Ruoroechiru -n- butyl sulfone, trifluoroethyl -t- butyl sulfone, trifluoromethyl -n- butyl sulfone, trifluoromethyl -t- butyl sulfone is high ion conductivity, preferable because the input-output characteristic is high.

One of the sulfone compounds may be used alone, or two or more thereof may be used in any combination and in any ratio.
The compounding amount of the sulfone compound is usually preferably at least 0.3% by volume, more preferably at least 1% by volume, still more preferably at least 5% by volume, and preferably at least 40% by volume in 100% by volume of the nonaqueous solvent. % By volume or less, more preferably 35% by volume or less, still more preferably 30% by volume
It is as follows.

Within this range, the effect of improving durability such as cycle characteristics and storage characteristics can be easily obtained, and the viscosity of the non-aqueous electrolyte can be adjusted to an appropriate range to avoid a decrease in electric conductivity. When charging / discharging the aqueous electrolyte battery at a high current density, it is easy to avoid a situation where the charge / discharge capacity retention rate decreases.

<When a cyclic carbonate having a fluorine atom is used as a non-aqueous solvent>
In the present invention, when a cyclic carbonate having a fluorine atom is used as a non-aqueous solvent, one of the non-aqueous solvents exemplified above is combined with a cyclic carbonate having a fluorine atom as a non-aqueous solvent other than the cyclic carbonate having a fluorine atom. And two or more of them may be used in combination with a cyclic carbonate having a fluorine atom.

For example, one of the preferable combinations of the non-aqueous solvent includes a combination mainly composed of a cyclic carbonate having a fluorine atom and a chain carbonate. Above all, the sum of the cyclic carbonate having a fluorine atom and the chain carbonate in the nonaqueous solvent is preferably 60% by volume.
The above, more preferably 80% by volume or more, even more preferably 90% by volume or more, and the ratio of the fluorine-containing cyclic carbonate to the total of the fluorine-containing cyclic carbonate and the chain carbonate is 3% by volume or more, preferably Is at least 5% by volume, more preferably 1%
0% by volume or more, more preferably 15% by volume or more, and usually 60% by volume or less, preferably 50% by volume or less, more preferably 40% by volume or less, further preferably 35% by volume or less, particularly preferably 30% by volume or less. %, Most preferably 20% by volume or less.

When a combination of these non-aqueous solvents is used, the balance between the cycle characteristics and the high-temperature storage characteristics (particularly, the remaining capacity and high-load discharge capacity after high-temperature storage) of the battery manufactured using the combination may be improved.
For example, as a specific example of a preferred combination of a cyclic carbonate having a fluorine atom and a chain carbonate,
Monofluoroethylene carbonate and dimethyl carbonate, monofluoroethylene carbonate and diethyl carbonate, monofluoroethylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate and dimethyl carbonate and ethyl methyl carbonate, monofluoro Examples include ethylene carbonate, diethyl carbonate, and ethyl methyl carbonate, and monofluoroethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate.

Among the combination of a cyclic carbonate having a fluorine atom and a chain carbonate, those containing a symmetric chain alkyl carbonate as the chain carbonate are more preferable, and particularly, monofluoroethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, and monomethyl ethylene carbonate are preferable. Those containing monofluoroethylene carbonate such as fluoroethylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate such as monofluoroethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, symmetric chain carbonates and asymmetric chain carbonates have cycle characteristics. And a large current discharge characteristic are preferable. Among them, the symmetric chain carbonate is preferably dimethyl carbonate, and the alkyl group of the chain carbonate preferably has 1 to 2 carbon atoms.

A preferable combination is a combination of the combination of the cyclic carbonate having a fluorine atom and the chain carbonates further including a cyclic carbonate having no fluorine atom. Among them, the sum of the cyclic carbonate having a fluorine atom and the cyclic carbonate having no fluorine atom in the non-aqueous solvent is preferably at least 10% by volume, more preferably at least 15% by volume, further preferably at least 20% by volume. And the proportion of the cyclic carbonate having a fluorine atom to the total of the cyclic carbonate having a fluorine atom and the cyclic carbonate having no fluorine atom is 1 vol% or more, preferably 3 vol% or more, more preferably 5 vol% or more. , More preferably at least 10% by volume, particularly preferably at least 20% by volume, preferably at most 95% by volume, more preferably at most 85% by volume, still more preferably at most 75% by volume, particularly preferably at most 60% by volume. These are:

When a cyclic carbonate having no fluorine atom is contained in this concentration range, the electric conductivity of the electrolytic solution can be maintained while forming a stable protective film on the negative electrode.
Specific examples of a preferred combination of a cyclic carbonate having a fluorine atom, a cyclic carbonate having no fluorine atom and a chain carbonate,
Monofluoroethylene carbonate, ethylene carbonate and dimethyl carbonate,
Monofluoroethylene carbonate, ethylene carbonate and diethyl carbonate, monofluoroethylene carbonate, ethylene carbonate and ethyl methyl carbonate,
Monofluoroethylene carbonate, ethylene carbonate, dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate and ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and ethylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and ethylene Carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate, monofluoroethylene carbonate, propylene carbonate, diethyl carbonate, monofluoroethylene carbonate, propylene carbonate, ethyl methyl carbonate Carbonate, monofluoroethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate and propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and propylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate And propylene carbonate and dimethyl carbonate and diethyl carbonate and ethyl methyl carbonate,
Monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate And propylene carbonate, dimethyl carbonate and diethyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate and ethyl carbonate Methyl carbonate, mono-fluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate and ethyl methyl carbonate.

Among the combination of a cyclic carbonate having a fluorine atom and a cyclic carbonate having no fluorine atom and a chain carbonate, those containing an asymmetric chain alkyl carbonate as the chain carbonate are more preferable, particularly,
Monofluoroethylene carbonate and ethylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and propylene carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and ethylene carbonate and dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and propylene carbonate and dimethyl carbonate Ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and propylene carbonate Ethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and ethylene carbonate, dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, monofluoroethylene carbonate and propylene carbonate And dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, monofluoroethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate. Since the balance of Le characteristics and large-current discharge characteristics may preferably. Among them, the asymmetric chain carbonates are preferably ethyl methyl carbonate, and the alkyl group of the chain carbonate preferably has 1 to 2 carbon atoms.

When ethyl methyl carbonate is contained in the non-aqueous solvent, the proportion of ethyl methyl carbonate in the total non-aqueous solvent is preferably at least 10% by volume, more preferably at least 20% by volume.
Or more, more preferably 25% by volume or more, particularly preferably 30% by volume or more,
When it is contained in an amount of preferably 95% by volume or less, more preferably 90% by volume or less, still more preferably 85% by volume or less, and particularly preferably 80% by volume or less, the load characteristics of the battery may be improved.
In the combination mainly composed of a cyclic carbonate having a fluorine atom and a chain carbonate, in addition to the cyclic carbonate having no fluorine atom, a cyclic carboxylic acid ester, a chain carboxylic acid ester, a cyclic ether, a chain Other solvents such as ether ethers, sulfur-containing organic solvents, phosphorus-containing organic solvents, and fluorine-containing aromatic solvents may be mixed.

<When a cyclic carbonate having a fluorine atom is used as an auxiliary>
In the present invention, when a cyclic carbonate having a fluorine atom is used as an auxiliary, one kind of the non-aqueous solvent exemplified above may be used alone as the non-aqueous solvent other than the cyclic carbonate having a fluorine atom, or two or more kinds may be used. May be used in any combination and in any ratio.
For example, one of the preferable combinations of the non-aqueous solvent includes a combination mainly composed of a cyclic carbonate having no fluorine atom and a chain carbonate.

Among them, the total of the cyclic carbonate having no fluorine atom and the chain carbonate in the nonaqueous solvent is preferably 70% by volume or more, more preferably 80% by volume or more, further preferably 90% by volume or more, and The proportion of the cyclic carbonate having no fluorine atom to the total of the cyclic carbonate and the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, still more preferably 15% by volume or more, and preferably It is 50% by volume or less, more preferably 35% by volume or less, further preferably 30% by volume or less, particularly preferably 25% by volume or less.

When a combination of these non-aqueous solvents is used, the balance between the cycle characteristics and the high-temperature storage characteristics (particularly, the remaining capacity and high-load discharge capacity after high-temperature storage) of the battery manufactured using the combination may be improved.
For example, specific examples of preferred combinations of a cyclic carbonate and a chain carbonate having no fluorine atom include:
Ethylene carbonate and dimethyl carbonate, ethylene carbonate and diethyl carbonate, ethylene carbonate and ethyl methyl carbonate, ethylene carbonate and dimethyl carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate and ethyl methyl carbonate, ethylene carbonate and diethyl carbonate and ethyl methyl carbonate, ethylene carbonate And dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate, propylene carbonate and ethyl methyl carbonate, propylene carbonate, ethyl methyl carbonate and diethyl carbonate, propylene carbonate, ethyl methyl carbonate and dimethyl carbonate.

Among the combination of a cyclic carbonate having no fluorine atom and a chain carbonate, those containing an asymmetric chain alkyl carbonate as the chain carbonate are more preferable, particularly, ethylene carbonate and ethyl methyl carbonate, propylene carbonate and ethyl Methyl carbonate, ethylene carbonate and ethyl methyl carbonate and dimethyl carbonate, ethylene carbonate and ethyl methyl carbonate and diethyl carbonate, propylene carbonate and ethyl methyl carbonate and dimethyl carbonate,
Propylene carbonate, ethyl methyl carbonate and diethyl carbonate are preferred because they have a good balance between cycle characteristics and large current discharge characteristics.

Among them, the asymmetric chain carbonate is preferably ethyl methyl carbonate,
Further, the alkyl group of the chain carbonate preferably has 1 to 2 carbon atoms.
When dimethyl carbonate is contained in the non-aqueous solvent, the proportion of dimethyl carbonate in the total non-aqueous solvent is preferably at least 10% by volume, more preferably at least 20% by volume, still more preferably at least 25% by volume, particularly preferably at least 25% by volume. It is preferably at least 30% by volume, more preferably at most 90% by volume, more preferably at most 80% by volume, further preferably at most 75% by volume,
Particularly preferably, when it is contained in a range of 70% by volume or less, the load characteristics of the battery may be improved.

Above all, it contains dimethyl carbonate and ethyl methyl carbonate, and by increasing the content of dimethyl carbonate more than the content of ethyl methyl carbonate, the battery characteristics after high-temperature storage are improved while maintaining the electrical conductivity of the electrolytic solution. Is preferred.
The volume ratio of dimethyl carbonate to ethyl methyl carbonate (dimethyl carbonate / ethyl methyl carbonate) in the total nonaqueous solvent is 1.1 or more in terms of improving the electric conductivity of the electrolytic solution and improving the battery characteristics after storage. Is preferably 1.5 or more, more preferably 2.5 or more. The volume ratio (dimethyl carbonate / ethyl methyl carbonate) is preferably 40 or less, more preferably 20 or less, still more preferably 10 or less, and particularly preferably 8 or less, from the viewpoint of improving battery characteristics at low temperatures.

In the combination mainly composed of a cyclic carbonate having no fluorine atom and a chain carbonate, a cyclic carboxylic acid ester, a chain carboxylic acid ester, a cyclic ether, a chain ether, a sulfur-containing organic solvent, a phosphorus-containing organic solvent, Other solvents such as an organic solvent and an aromatic fluorinated solvent may be mixed.
In addition, in this specification, the volume of the nonaqueous solvent is a measured value at 25 ° C., but for a solid such as ethylene carbonate at 25 ° C., the measured value at the melting point is used.

1-4. In the non-aqueous electrolyte battery of the present invention, a compound having a structure represented by the following general formula (A):
In addition, 0 to the total amount of the nitrile compound, the isocyanate compound, the difluorophosphate, the fluorosulfonate, the lithium bis (fluorosulfonyl) imide, the compound represented by the following general formula (B), and the nonaqueous electrolyte. Aside from at least one compound selected from the group consisting of cyclic carbonate compounds having a fluorine atom of 0.01% by mass or more and 50% by mass or less, an auxiliary agent may be appropriately used according to the purpose. As the auxiliary agent, a cyclic carbonate having a carbon-carbon unsaturated bond shown below, an acid anhydride compound, a vinylsulfonic acid ester compound,
An aromatic compound having 12 or less carbon atoms, a fluorinated unsaturated cyclic carbonate, a compound having a triple bond, other auxiliaries, and the like, and a cyclic carbonate having a carbon-carbon unsaturated bond,
Acid anhydride compounds are preferred.

1-4-1. Cyclic carbonate having a carbon-carbon unsaturated bond Cyclic carbonate having a carbon-carbon unsaturated bond (hereinafter referred to as “unsaturated cyclic carbonate”)
Is not particularly limited as long as it has a carbon-carbon double bond or a carbon-carbon triple bond, and any unsaturated carbonate can be used. Note that a cyclic carbonate having an aromatic ring is also included in the unsaturated cyclic carbonate.

As unsaturated cyclic carbonates,
Vinylene carbonates, ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon double bond or a carbon-carbon triple bond, phenyl carbonates, vinyl carbonates, allyl carbonates, catechol carbonates, and the like. .

As vinylene carbonates,
Vinylene carbonate, methyl vinylene carbonate, 4,5-dimethylvinylene carbonate, phenylvinylene carbonate, 4,5-diphenylvinylene carbonate,
Vinyl vinylene carbonate, 4,5-divinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, 4-fluorovinylene carbonate, 4-fluoro-5-methylvinylene carbonate, 4-fluoro-5-phenylvinylene carbonate, 4-fluoro-5-vinylvinylene carbonate, 4-allyl-5
-Fluorovinylene carbonate and the like.

Specific examples of ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon double bond or a carbon-carbon triple bond include:
Vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-
5-vinylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5-diethynylethylene carbonate, 4-methyl-5
-Ethynylethylene carbonate, 4-vinyl-5-ethynylethylene carbonate, 4
-Allyl-5-ethynylethylene carbonate, phenylethylene carbonate, 4,5
-Diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate,
4-allyl-5-phenylethylene carbonate, allylethylene carbonate, 4,5
-Diallylethylene carbonate, 4-methyl-5-allylethylene carbonate and the like.

Among them, particularly preferred unsaturated cyclic carbonates to be used in combination with the compound represented by the formula (1) include:
Vinylene carbonate, methylvinylene carbonate, 4,5-dimethylvinylene carbonate, vinylvinylene carbonate, 4,5-vinylvinylenecarbonate, allylvinylenecarbonate, 4,5-diallylvinylenecarbonate, vinylethylene carbonate, 4,5-divinylethylenecarbonate , 4-methyl-5-vinylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4-
Methyl-5-allyl ethylene carbonate, 4-allyl-5-vinyl ethylene carbonate, ethynyl ethylene carbonate, 4,5-diethynyl ethylene carbonate, 4-methyl-5-ethynyl ethylene carbonate, 4-vinyl-5-ethynyl ethylene carbonate Is mentioned. Vinylene carbonate, vinyl ethylene carbonate and ethynyl ethylene carbonate are particularly preferred because they form a more stable interfacial protective film.

The molecular weight of the unsaturated cyclic carbonate is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 80 or more and 250 or less. Within this range, the solubility of the unsaturated cyclic carbonate in the non-aqueous electrolyte can be easily ensured, and the effect of the present invention can be sufficiently exhibited. The molecular weight of the unsaturated cyclic carbonate is more preferably 85
And more preferably 150 or less.

The method for producing the unsaturated cyclic carbonate is not particularly limited, and it is possible to arbitrarily select and produce a known method.
As the unsaturated cyclic carbonate, one type may be used alone, or two or more types may be used in optional combination and ratio. The amount of the unsaturated cyclic carbonate to be compounded is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The amount of the unsaturated cyclic carbonate is preferably 0.001% by mass or more, more preferably 0.01% by mass, in 100% by mass of the nonaqueous electrolyte.
The content is 1% by mass or more, more preferably 0.1% by mass or more, preferably 5% by mass or less, more preferably 4% by mass or less, and still more preferably 3% by mass or less. Within this range, the non-aqueous electrolyte battery can easily exhibit a sufficient effect of improving the cycle characteristics, and the high-temperature storage characteristics are reduced, the amount of gas generated is increased, and the discharge capacity retention rate is reduced. Easy to avoid.

1-4-2. Acid anhydride compounds Acid anhydride compounds include carboxylic anhydrides, sulfuric anhydrides, nitric anhydrides, sulfonic anhydrides, phosphoric anhydrides, phosphorous anhydrides, and cyclic acid anhydrides, chains. The structure is not limited, as long as it is an acid anhydride compound, without any limitation such as being an acid anhydride.

Specific examples of the acid anhydride compound include, for example,
Malonic anhydride, succinic anhydride, glutaric anhydride, adipic anhydride, maleic anhydride, citraconic anhydride, 2,3-dimethylmaleic anhydride, glutaconic anhydride, itaconic anhydride, phthalic anhydride, phenylmaleic anhydride 2,3-diphenylmaleic anhydride, cyclohexane-1,2-dicarboxylic anhydride, 4-cyclohexene-1,2-dicarboxylic anhydride, 3,4,5,6-tetrahydrophthalic anhydride, , 4'-oxydiphthalic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, methyl-5-norbornene-2
, 3-dicarboxylic anhydride, phenylsuccinic anhydride, 2-phenylglutaric anhydride,
Allyl succinic anhydride, 2-buten-11-yl succinic anhydride, (2-methyl-2-propenyl) succinic anhydride, tetrafluorosuccinic anhydride, diacetyl-tartaric anhydride, bicyclo [2.
2.2] Oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5- (2,5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2- Dicarboxylic anhydride, methacrylic anhydride, acrylic anhydride, crotonic anhydride, methanesulfonic anhydride, trifluoromethanesulfonic anhydride, nonafluorobutanesulfonic anhydride,
Acetic anhydride and the like.

Of these,
Succinic anhydride, maleic anhydride, citraconic anhydride, phenylmaleic anhydride, bicyclo [2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, 5- (2 ,
5-dioxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, allylsuccinic anhydride, acetic anhydride, methacrylic anhydride, acrylic anhydride, and methanesulfonic anhydride. Particularly preferred.

As the acid anhydride compound, one kind may be used alone, and two kinds or more may be used in optional combination and ratio.
The amount of the acid anhydride compound to be added to the entire non-aqueous electrolyte of the present invention is not limited, and is arbitrary as long as the effect of the present invention is not significantly impaired.
1% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, further preferably The content is 2% by mass or less, particularly preferably 1% by mass or less, most preferably 0.5% by mass or less.
When the above range is satisfied, effects such as output characteristics, load characteristics, low-temperature characteristics, cycle characteristics, and high-temperature storage characteristics are further improved.

1-4-4. Vinyl Sulfonate Compound The type of the vinyl sulfonic acid ester compound is not particularly limited as long as the compound has a vinyl sulfonic acid ester structure in the molecule.
Specific examples of the vinyl sulfonic acid ester compound include, for example,

Among them,

Is preferred.
As the vinyl sulfonic acid ester compound, one kind may be used alone, and two kinds or more may be used in optional combination and ratio. The amount of the vinyl sulfonic acid ester compound to be added to the whole non-aqueous electrolyte of the present invention is not limited, and is arbitrary as long as the effect of the present invention is not significantly impaired. 001% by mass or more, preferably 0.01%
% By mass or more, more preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, particularly preferably 1% by mass or less. %, Most preferably 0.5% by mass or less. When the above range is satisfied, effects such as output characteristics, load characteristics, low-temperature characteristics, cycle characteristics, and high-temperature storage characteristics are further improved.

1-4-5. Aromatic compound having 12 or less carbon atoms The type of the aromatic compound having 12 or less carbon atoms is not particularly limited as long as the compound has 12 or less carbon atoms in the molecule.
Specific examples of the aromatic compound having 12 or less carbon atoms include, for example,
Biphenyl, alkylbiphenyl, cyclohexylbenzene, t-butylbenzene, t
Aromatic compounds such as amylbenzene, diphenyl ether and dibenzofuran; partially fluorinated products of the above aromatic compounds such as 2-fluorobiphenyl, o-cyclohexylfluorobenzene and p-cyclohexylfluorobenzene;
Fluorinated anisole compounds such as 2,4-difluoroanisole, 2,5-difluoroanisole, 2,6-difluoroanisole, and 3,5-difluoroanisole. Among them,
Biphenyl, alkylbiphenyl, cyclohexylbenzene, t-butylbenzene, t
-Aromatic compounds such as amylbenzene, diphenyl ether and dibenzofuran are preferred.

These may be used alone or in combination of two or more. When two or more kinds are used in combination, in particular, a combination of cyclohexylbenzene and t-butylbenzene or t-amylbenzene, or an oxygen-free aromatic such as biphenyl, alkylbiphenyl, cyclohexylbenzene, t-butylbenzene, or t-amylbenzene. It is preferable to use at least one member selected from group III compounds and at least one member selected from oxygen-containing aromatic compounds such as diphenyl ether and dibenzofuran in view of the balance of high-temperature storage characteristics.

The aromatic compound having 12 or less carbon atoms is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The overcharge inhibitor is usually 0.001% by mass in 100% by mass of the non-aqueous electrolyte.
Or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and usually 1% by mass or more.
The content is 0% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, further preferably 2% by mass or less, and particularly preferably 1% by mass or less. Within this range,
It is easy to sufficiently exhibit the effect of the overcharge preventing agent, and it is also easy to avoid a situation in which battery characteristics such as high-temperature storage characteristics are deteriorated.

1-4-6. Chain carboxylic acid ester The chain carboxylic acid ester preferably has 3 to 7 carbon atoms. Specifically, methyl acetate, ethyl acetate, -n-propyl acetate, isopropyl acetate, -n-butyl acetate, isobutyl acetate, -t-butyl acetate, methyl propionate, ethyl propionate, -n-propyl propionate, Isopropyl propionate, n-butyl propionate, isobutyl propionate, t-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, n-isobutyrate Propyl,
And isopropyl isobutyrate.

Among them, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, methyl butyrate, ethyl butyrate, and the like, due to a decrease in viscosity. It is preferable from the viewpoint of improving ionic conductivity. More preferably, methyl propionate, ethyl propionate, propionic acid-n-
Propyl and isopropyl propionate, particularly preferably methyl propionate and ethyl propionate, are preferred.

As the chain carboxylic acid ester, one type may be used alone, or two or more types may be used in optional combination and ratio.
The amount of the chain carboxylic acid ester is usually in 100% by volume of the non-aqueous solvent, preferably 10% by volume.
% By volume or more, more preferably 15% by volume or more. By setting the lower limit in this way,
The electric conductivity of the non-aqueous electrolyte solution is improved, and the large-current discharge characteristics of the non-aqueous electrolyte battery are easily improved. The amount of the chain carboxylic acid ester is preferably 60% by volume or less, more preferably 50% by volume or less, further preferably 30% by volume or less in 100% by volume of the nonaqueous solvent.
It is particularly preferably at most 20% by volume, most preferably at most 10% by volume. By setting the upper limit in this manner, an increase in the negative electrode resistance is suppressed, and the large-current discharge characteristics and cycle characteristics of the nonaqueous electrolyte battery can be easily set in favorable ranges.

1-4-6. Fluorinated unsaturated cyclic carbonate As the fluorinated cyclic carbonate, it is also preferable to use a cyclic carbonate having an unsaturated bond and a fluorine atom (hereinafter sometimes referred to as “fluorinated unsaturated cyclic carbonate”). If the number of fluorine atoms in the fluorinated unsaturated cyclic carbonate is 1 or more,
There is no particular limitation. Among them, the fluorine atom is usually 6 or less, preferably 4 or less, and 1 or 2
Are most preferred.

Examples of the fluorinated unsaturated cyclic carbonate include a fluorinated vinylene carbonate derivative, a fluorinated ethylene carbonate derivative substituted with a substituent having an aromatic ring or a carbon-carbon double bond, and the like.
As the fluorinated vinylene carbonate derivative, 4-fluorovinylene carbonate,
4-fluoro-5-methylvinylene carbonate, 4-fluoro-5-phenylvinylene carbonate, 4-allyl-5-fluorovinylene carbonate, 4-fluoro-5-vinylvinylene carbonate and the like can be mentioned.

As a fluorinated ethylene carbonate derivative substituted with a substituent having an aromatic ring or a carbon-carbon double bond,
4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-4-vinylethylene Carbonate, 4
4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro -4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate,
5-difluoro-4,5-diallylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5-difluoro- 4-phenylethylene carbonate and the like.

Among them, preferred fluorinated unsaturated cyclic carbonates include:
4-fluorovinylene carbonate, 4-fluoro-5-methylvinylene carbonate, 4-fluoro-5-vinylvinylene carbonate, 4-allyl-5-fluorovinylene carbonate, 4-fluoro-4-vinylethylene carbonate, 4-fluoro- 4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-
Diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate, and 4,5-difluoro-4,5-diallylethylene carbonate are more preferably used because they form a stable interface protective film.

The molecular weight of the fluorinated unsaturated cyclic carbonate is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The molecular weight is preferably 50 or more and 250 or less. Within this range, the solubility of the fluorinated cyclic carbonate in the non-aqueous electrolytic solution is easily ensured, and the effect of the present invention is easily exhibited.
The method for producing the fluorinated unsaturated cyclic carbonate is not particularly limited, and any known method can be used for production. The molecular weight is more preferably 100 or more, and more preferably 200 or less.

As the fluorinated unsaturated cyclic carbonate, one kind may be used alone, and two kinds or more may be used in optional combination and ratio. The blending amount of the fluorinated unsaturated cyclic carbonate is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired.
The compounding amount of the fluorinated unsaturated cyclic carbonate is usually 0.01% by mass or more, more preferably 0.1% by mass or more, and still more preferably 0.1% by mass or more in 100% by mass of the nonaqueous electrolyte.
5% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less,
It is more preferably at most 3% by mass, particularly preferably at most 2% by mass.
Within this range, the non-aqueous electrolyte battery tends to exhibit a sufficient effect of improving the cycle characteristics, and the high-temperature storage characteristics are reduced, the amount of generated gas is increased, and the discharge capacity retention rate is reduced. Easy to avoid.

1-4-7. Compound having a triple bond The compound having a triple bond is not particularly limited as long as it has one or more triple bonds in the molecule.
Specific examples of the compound having a triple bond include, for example, the following compounds.
1-pentyne, 2-pentyne, 1-hexyne, 2-hexyne, 3-hexyne, 1-heptin, 2-heptin, 3-heptin, 1-octin, 2-octyne, 3-octyne, 4-
Octin, 1-nonine, 2-nonine, 3-nonine, 4-nonine, 1-dodecine, 2-dodecine, 3-dodecine, 4-dodecine, 5-dodecine, phenylacetylene, 1-phenyl-1-propyne, 1 -Phenyl-2-propyne, 1-phenyl-1-butyne, 4-phenyl-1-butyne, 4-phenyl-1-butyne, 1-phenyl-1-pentyne, 5-phenyl-1-pentyne, 1-phenyl Hydrocarbon compounds such as -1-hexyne, 6-phenyl-1-hexyne, diphenylacetylene, 4-ethynyltoluene and dicyclohexylacetylene;

2-propynylmethyl carbonate, 2-propynylethyl carbonate, 2-propynylpropyl carbonate, 2-propynylbutyl carbonate, 2-propynylphenyl carbonate, 2-propynylcyclohexyl carbonate, di-2-propynyl carbonate, 1-methyl-2-propynyl Methyl carbonate, 1,1-dimethyl-2-propynylmethyl carbonate, 2-butynylmethyl carbonate, 3-butynylmethyl carbonate, 2-pentynylmethyl carbonate, 3-pentynylmethyl carbonate,
Monocarbonates such as 4-pentynylmethyl carbonate;
2-butyne-1,4-diol dimethyl dicarbonate, 2-butyne-1,4-diol diethyl dicarbonate, 2-butyne-1,4-diol dipropyl dicarbonate, 2-butyne-1,4-diol dibutyl Dicarbonate, 2-butyne-1,4-
Dicarbonates such as diol diphenyl dicarbonate and 2-butyne-1,4-diol dicyclohexyl dicarbonate;

2-propynyl acetate, 2-propynyl propionate, 2-propynyl butyrate, benzoic acid 2
-Propynyl, 2-propynyl cyclohexylcarboxylate, 1,1-dimethyl-2-acetic acid
Propynyl, 1,1-dimethyl-2-propynyl propionate, 1,1-dimethyl butyrate
2-propynyl, 1,1-dimethyl-2-propynyl benzoate, 1,1-dimethyl-2-propynyl cyclohexylcarboxylate, 2-butynyl acetate, 3-butynyl acetate, 2-acetic acid 2-
Pentynyl, 3-pentynyl acetate, 4-pentynyl acetate, methyl acrylate, ethyl acrylate, propyl acrylate, vinyl acrylate, 2-propenyl acrylate, 2-butenyl acrylate, 3-butenyl acrylate, methyl methacrylate, Ethyl methacrylate,
Propyl methacrylate, vinyl methacrylate, 2-propenyl methacrylate, 2-butenyl methacrylate, 3-butenyl methacrylate, methyl 2-propinate, ethyl 2-propinate, propyl 2-propinate, vinyl 2-propinate, 2-propenyl 2-propenylate, 2-butenyl 2-propinate, 3-butenyl 2-propinate, methyl 2-butyrate, 2
-Ethyl butyrate, propyl 2-butyrate, vinyl 2-butyrate, 2-propenyl 2-butyrate, 2-butenyl 2-butyrate, 3-butenyl 2-butyrate, methyl 3-butyrate,
Ethyl 3-butyrate, propyl 3-butyrate, vinyl 3-butyrate, 2-propenyl 3-butyrate, 2-butenyl 3-butyrate, 3-butenyl 3-butyrate, methyl 2-pentyate, 2-methylbutyrate Ethyl pentate, 2-propyl pentate, 2-vinyl pentate, 2-propenyl 2-pentate, 2-butenyl 2-pentate, 3-butenyl 2-pentate, 3
-Methyl pentate, ethyl 3-pentate, propyl 3-pentate, vinyl 3-pentate, 2-propenyl 3-pentate, 2-butenyl 3-pentate, 3-butenyl 3-pentate, 4-pentyne Monocarboxylic acid esters such as methyl oxalate, ethyl 4-pentate, propyl 4-pentate, vinyl 4-pentate, 2-propenyl 4-pentate, 2-butenyl 4-pentate, and 3-butenyl 4-pentate ;

2-butyne-1,4-diol diacetate, 2-butyne-1,4-diol dipropionate, 2-butyne-1,4-diol dibutyrate, 2-butyne-1,4-diol dibenzoate, 2-butyne Dicarboxylic acid esters such as -1,4-diol dicyclohexanecarboxylate;
Methyl oxalate 2-propynyl, ethyl oxalate 2-propynyl, propyl oxalate 2-propynyl, 2-propynyl vinyl oxalate, allyl oxalate 2-propynyl, di-2-propynyl oxalate, 2-butynyl methyl oxalate, 2-butynylethyl oxalate, 2-butynylpropyl oxalate, 2-butynylvinyl oxalate, 2-butynyl allyl oxalate, di-2-butynyl oxalate, 3-butynylmethyl oxalate,
Oxalic acid diesters such as 3-butynylethyl oxalate, 3-butynylpropyl oxalate, 3-butynylvinyl oxalate, allyl-3-butynyl oxalate and di-3-butynyl oxalate;

Methyl (2-propynyl) (vinyl) phosphine oxide, divinyl (2-propynyl) phosphine oxide, di (2-propynyl) (vinyl) phosphine oxide, di (2-
Propenyl) 2 (-propynyl) phosphine oxide, di (2-propynyl) (2-propenyl) phosphine oxide, di (3-butenyl) (2-propynyl) phosphine oxide, and di (2-propynyl) (3-butenyl) A phosphine oxide such as a phosphine oxide;
2-propynyl methyl (2-propenyl) phosphinate, 2-propynyl 2-butenyl (methyl) phosphinate, 2-propynyl di (2-propenyl) phosphinate, di (3-
2-propynyl butenyl) phosphinate, 1,1 methyl (2-propenyl) phosphinate
-Dimethyl-2-propynyl, 1,1-dimethyl 2-butenyl (methyl) phosphinate
2-propynyl, 1,1-dimethyl-2-propynyl di (2-propenyl) phosphinate, and 1,1-dimethyl-2-propynyl di (3-butenyl) phosphinate, methyl (2
-Propynyl) phosphinic acid 2-propenyl, methyl (2-propynyl) phosphinic acid 3
-Butenyl, 2-propenyl di (2-propynyl) phosphinate, di (2-propynyl)
Phosphinic esters such as 3-butenyl phosphinate, 2-propenyl 2-propenyl (2-propenyl) phosphinate, and 3-butenyl 2-propynyl (2-propenyl) phosphinate;

Methyl 2-propenylphosphonate 2-propynyl, methyl 2-butenylphosphonate (
2-propynyl), 2-propenylphosphonic acid (2-propynyl) (2-propenyl),
3-butenylphosphonic acid (3-butenyl) (2-propynyl), 2-propenylphosphonic acid (1,1-dimethyl-2-propynyl) (methyl), 2-butenylphosphonic acid (1,1
-Dimethyl-2-propynyl) (methyl), 2-propenylphosphonic acid (1,1-dimethyl-2-propynyl) (2-propenyl), and 3-butenylphosphonic acid (3-butenyl) (1,1-dimethyl- 2-propynyl), methylphosphonic acid (2-propynyl) (2-
Propenyl), methylphosphonic acid (3-butenyl) (2-propynyl), methylphosphonic acid (1,1-dimethyl-2-propynyl) (2-propenyl), methylphosphonic acid (3-propenyl)
(Butenyl) (1,1-dimethyl-2-propynyl), ethyl phosphonic acid (2-propynyl) (2-propenyl), ethyl phosphonic acid (3-butenyl) (2-propynyl), ethyl phosphonic acid (1,1- Phosphonate esters such as dimethyl-2-propynyl) (2-propenyl), and ethylphosphonic acid (3-butenyl) (1,1-dimethyl-2-propynyl);

(Methyl) phosphate (2-propenyl) (2-propynyl), (ethyl) phosphate (2-propenyl) (2-propynyl), (2-butenyl) phosphate (methyl) (2-propynyl)
, Phosphoric acid (2-butenyl) (ethyl) (2-propynyl), phosphoric acid (1,1-dimethyl-
2-propynyl) (methyl) (2-propenyl), (1,1-dimethyl-2-propynyl) phosphate (ethyl) (2-propenyl), (2-butenyl) phosphate (1,1-dimethyl-
Phosphoric acid esters such as 2-propynyl) (methyl) and (2-butenyl) (ethyl) phosphate (1,1-dimethyl-2-propynyl);
Of these, compounds having an alkynyloxy group are preferable because they form the negative electrode coating more stably in the electrolytic solution.

further,
2-propynylmethyl carbonate, di-2-propynyl carbonate, 2-butyne-
1,4-diol dimethyl dicarbonate, 2-propynyl acetate, 2-butyne-1,4
Compounds such as -diol diacetate, methyl oxalate 2-propynyl and di-2-propynyl oxalate are particularly preferred from the viewpoint of improving storage characteristics.

As the compound having a triple bond, one type may be used alone, or two or more types may be used in optional combination and ratio. The compounding amount of the compound having a triple bond with respect to the whole non-aqueous electrolyte of the present invention is not limited, and is arbitrary as long as the effect of the present invention is not significantly impaired. 01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and usually 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less. Let it. If the above range is satisfied, output characteristics,
Effects such as load characteristics, low-temperature characteristics, cycle characteristics, and high-temperature storage characteristics are further improved.

1-4-8. Other auxiliaries As other auxiliaries, known auxiliaries other than the above auxiliaries can be used. Other auxiliaries include
Carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate;
2,4,8,10-tetraoxaspiro [5.5] undecane, 3,9-divinyl-2
Spiro compounds such as, 4,8,10-tetraoxaspiro [5.5] undecane;
Ethylene sulfite, methyl fluorosulfonate, ethyl fluorosulfonate, methyl methanesulfonate, ethyl methanesulfonate, busulfan, sulfolene, diphenylsulfone, N, N-dimethylmethanesulfonamide, N, N-diethylmethanesulfonamide, vinyl Methyl sulfonate, ethyl vinyl sulfonate, allyl vinyl sulfonate, propargyl vinyl sulfonate, methyl allyl sulfonate, ethyl allyl sulfonate, allyl allyl sulfonate, propargyl allyl sulfonate, 1,2-bis (vinyl sulfonyloxy) Sulfur-containing compounds such as ethane;

Nitrogen-containing compounds such as 1-methyl-2-pyrrolidinone, 1-methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-methylsuccinimide;
Trimethyl phosphite, triethyl phosphite, triphenyl phosphite, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, dimethyl methyl phosphonate, diethyl ethyl phosphonate, dimethyl vinyl phosphonate, diethyl vinyl phosphonate, dimethyl phosphine Phosphorus-containing compounds such as methyl acrylate, ethyl diethyl phosphinate, trimethyl phosphine oxide, and triethyl phosphine oxide;

Hydrocarbon compounds such as heptane, octane, nonane, decane and cycloheptane;
Fluorinated aromatic compounds such as fluorobenzene, difluorobenzene, hexafluorobenzene, benzotrifluoride;
And the like. These may be used alone or in combination of two or more. By adding these auxiliaries, the capacity retention characteristics after high-temperature storage and the cycle characteristics can be improved.

The amount of the other auxiliaries is not particularly limited, and is arbitrary as long as the effects of the present invention are not significantly impaired. The other auxiliary agent is preferably 0.01% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte. Within this range, the effects of the other auxiliary agents can be sufficiently exhibited, and a situation in which the battery characteristics such as high-load discharge characteristics are deteriorated can be easily avoided.
The compounding amount of the other auxiliaries is more preferably 0.1% by mass or more, and further preferably 0.2% by mass.
%, More preferably 3% by mass or less, further preferably 1% by mass or less.

As described above, the non-aqueous electrolyte described above includes those present inside the non-aqueous electrolyte battery according to the present invention.
Specifically, the components of the non-aqueous electrolyte such as a lithium salt, a solvent, and an auxiliary agent are separately synthesized, and the non-aqueous electrolyte is adjusted from substantially isolated ones by the method described below. In the case of a non-aqueous electrolyte in a non-aqueous electrolyte obtained by injecting into a separately assembled battery, or the components of the non-aqueous electrolyte of the present invention are individually put in the battery and When the same composition as that of the non-aqueous electrolyte of the present invention is obtained by mixing at the same time, the compound constituting the non-aqueous electrolyte of the present invention is further generated in the non-aqueous electrolyte battery, and the A case where the same composition as that of the aqueous electrolyte is obtained is also included.

2. Battery Configuration The non-aqueous electrolyte battery of the present invention is suitable for use as an electrolyte for a secondary battery, for example, a lithium secondary battery among non-aqueous electrolyte batteries. Hereinafter, a non-aqueous electrolyte battery using the non-aqueous electrolyte of the present invention will be described.
The non-aqueous electrolyte battery of the present invention can have a known structure, and typically includes a negative electrode and a positive electrode capable of inserting and extracting ions (for example, lithium ions), and the above-described non-aqueous electrolyte of the present invention. And a liquid.

2-1. Negative electrode The negative electrode active material used for the negative electrode is described below. The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release lithium ions. As a specific example,
Examples include carbonaceous materials, alloy materials, and lithium-containing metal composite oxide materials. These are 1
The species may be used alone, or two or more species may be used in any combination.

<Negative electrode active material>
Examples of the negative electrode active material include carbonaceous materials, alloy materials, and lithium-containing metal composite oxide materials.
Examples of the carbonaceous material include (1) natural graphite, (2) artificial graphite, (3) amorphous carbon, (4) carbon-coated graphite, (5) graphite-coated graphite, and (6) resin-coated graphite. .

(1) Examples of the natural graphite include flaky graphite, flaky graphite, soil graphite, and / or graphite particles obtained by subjecting such graphite to a material such as spheroidization or densification. Among these, spherical or ellipsoidal graphite subjected to a spheroidizing treatment is particularly preferable from the viewpoint of the filling properties of the particles and the charge / discharge rate characteristics.
As an apparatus used for the spheroidizing treatment, for example, an apparatus that repeatedly applies mechanical action such as compression, friction, and shearing force including particle interaction mainly on impact force to particles can be used.
Specifically, the casing has a rotor with a large number of blades installed inside, and the rotor rotates at high speed, causing mechanical effects such as impact compression, friction, and shearing force on the carbon material introduced inside. And a device for performing a sphering treatment is preferable. Further, it is preferable to have a mechanism for repeatedly giving a mechanical action by circulating the carbon material.

For example, when the spheroidizing process is performed using the above-described apparatus, the peripheral speed of the rotating rotor is set to 30 to
It is preferably 100 m / sec, more preferably 40 to 100 m / sec, and 50 to 100 m / sec.
More preferably, the speed is 100 m / sec. In addition, the treatment can be carried out simply by passing the carbonaceous material, but it is preferable that the treatment is carried out by circulating or retaining in the apparatus for 30 seconds or more, and the treatment is preferably carried out by circulating or retaining in the apparatus for 1 minute or more. More preferred.

(2) As artificial graphite, coal tar pitch, coal-based heavy oil, atmospheric residual oil, petroleum-based heavy oil, aromatic hydrocarbon, nitrogen-containing cyclic compound, sulfur-containing cyclic compound, polyphenylene, polyvinyl chloride, Organic compounds such as polyvinyl alcohol, polyacrylonitrile, polyvinyl butyral, natural polymers, polyphenylene sulfide, polyphenylene oxide, furfuryl alcohol resin, phenol-formaldehyde resin, and imide resin
Examples thereof include those produced by graphitization at a temperature of 500 ° C. or higher, usually 3200 ° C. or lower, and pulverized and / or classified as necessary. In this case, a silicon-containing compound or a boron-containing compound can be used as a graphitization catalyst. Another example is artificial graphite obtained by graphitizing mesocarbon microbeads separated in a pitch heat treatment process. Further, artificial graphite as granulated particles composed of primary particles is also included. For example, by mixing a graphitizable carbonaceous material powder such as mesocarbon microbeads or coke with a graphitizable binder such as tar and pitch and a graphitizing catalyst, graphitizing, and pulverizing as necessary. Examples of the obtained graphite particles include a plurality of flat particles, which are aggregated or bonded so that the orientation planes are non-parallel.

(3) As the amorphous carbon, a graphitizable carbon precursor such as tar or pitch is used as a raw material,
Amorphous carbon particles heat-treated at least once in a non-graphitizable temperature range (range of 400 to 2200 ° C.) and amorphous carbon particles heat-treated using a non-graphitizable carbon precursor such as a resin as a raw material are exemplified. Can be

(4) The carbon-coated graphite can be obtained by mixing natural graphite and / or artificial graphite with a carbon precursor which is an organic compound such as tar, pitch or resin, and subjecting the mixture to heat treatment at least once in the range of 400 to 2300 ° C. A carbon graphite composite in which natural graphite and / or artificial graphite is used as nuclear graphite, and amorphous carbon covers the nuclear graphite. The form of the composite may cover the entire surface or a part of the surface, or may be a composite of a plurality of primary particles using the carbon derived from the carbon precursor as a binder. In addition, hydrocarbon gas such as benzene, toluene, methane, propane and aromatic volatiles is reacted at high temperature with natural graphite and / or artificial graphite to deposit carbon on the graphite surface (CVD).
By doing so, a carbon-graphite composite can also be obtained.

(5) As the graphite-coated graphite, natural graphite and / or artificial graphite and a carbon precursor of an easily graphitizable organic compound such as tar, pitch and resin are mixed, and once mixed at a temperature of about 2400 to 3200 ° C. Natural graphite and / or artificial graphite obtained by the above heat treatment is used as nuclear graphite, and graphite-coated graphite in which the graphitized material covers the whole or a part of the surface of the nuclear graphite is exemplified.
(6) As the resin-coated graphite, a mixture of natural graphite and / or artificial graphite and a resin is used.
Resin-coated graphite in which natural graphite and / or artificial graphite obtained by drying at a temperature of less than ° C is used as core graphite and a resin or the like coats the core graphite.

Further, as the carbonaceous materials (1) to (6), one kind may be used alone, and two kinds or more may be used in optional combination and ratio.
Examples of the organic compound such as tar, pitch and resin used in the above (2) to (5) include coal-based heavy oil, direct current-based heavy oil, cracked petroleum heavy oil, aromatic hydrocarbon, and N-ring compound. , An S ring compound, polyphenylene, an organic synthetic polymer, a natural polymer, a carbonizable organic compound selected from the group consisting of a thermoplastic resin and a thermosetting resin. The raw material organic compound may be used by dissolving it in a low molecular weight organic solvent in order to adjust the viscosity at the time of mixing.

Further, as the natural graphite and / or artificial graphite as a raw material of the nuclear graphite, natural graphite subjected to a spheroidizing treatment is preferable.
As the alloy-based material used as the negative electrode active material, as long as it can occlude and release lithium, simple lithium, a simple metal and an alloy forming a lithium alloy, or oxides, carbides, nitrides, silicides, and sulfides thereof Or a compound such as a phosphide, and is not particularly limited. The elemental metal or alloy forming the lithium alloy is preferably a material containing a metal or metalloid element of group 13 and 14 (that is, excluding carbon), and more preferably an elemental metal of aluminum, silicon and tin, and An alloy or compound containing these atoms. One of these may be used alone, or two or more thereof may be used in any combination and in any ratio.

<Physical properties of carbonaceous materials>
When a carbonaceous material is used as the negative electrode active material, the material preferably has the following physical properties.
(X-ray parameters)
The d value (interlayer distance) of the lattice plane (002 plane) of the carbonaceous material obtained by X-ray diffraction according to the Gakushin method is usually 0.335 nm or more, usually 0.360 nm or less, and 0.350 n
m or less, more preferably 0.345 nm or less. Further, the crystallite size (Lc) of the carbonaceous material determined by X-ray diffraction by the Gakushin method is preferably 1.0 nm or more,
Above all, it is more preferable that the thickness be 1.5 nm or more.

(Volume-based average particle size)
The volume-based average particle diameter of the carbonaceous material is a volume-based average particle diameter (median diameter) determined by a laser diffraction / scattering method, and is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and more preferably 7 μm. Above is particularly preferable, and usually 100 μm or less,
μm or less, more preferably 40 μm or less, still more preferably 30 μm or less.
Particularly preferred is 5 μm or less.

If the volume-based average particle size is below the above range, the irreversible capacity increases, which may lead to a loss of the initial battery capacity. On the other hand, if it exceeds the above range, an uneven coating surface is likely to be formed when the electrode is manufactured by coating, which may be undesirable in a battery manufacturing process.
The volume-based average particle size is measured by dispersing a carbon powder in a 0.2% by mass aqueous solution (about 10 mL) of a surfactant, polyoxyethylene (20) sorbitan monolaurate, and then performing a laser diffraction / scattering type particle size distribution. (For example, LA-700 manufactured by Horiba Ltd.). The median diameter determined by the measurement is defined as the volume-based average particle diameter of the carbonaceous material of the present invention.

(Raman R value)
The Raman R value of the carbonaceous material is a value measured using a laser Raman spectrum method,
Usually 0.01 or more, preferably 0.03 or more, more preferably 0.1 or more, and usually 1.5 or less, preferably 1.2 or less, more preferably 1 or less, and 0.5 or less. Is particularly preferred.

When the Raman R value is below the above range, the crystallinity of the particle surface becomes too high, and the number of sites where Li enters between layers may decrease with charge and discharge. That is, charge acceptability may decrease. In addition, when the negative electrode is densified by pressing after being applied to the current collector, the crystals are likely to be oriented in a direction parallel to the electrode plate, which may cause a decrease in load characteristics.
On the other hand, if it exceeds the above range, the crystallinity of the particle surface decreases, the reactivity with the non-aqueous electrolyte increases, and the efficiency may decrease and the gas generation may increase.

The measurement of the Raman spectrum is performed by using a Raman spectrometer (for example, a Raman spectrometer manufactured by JASCO Corporation) to allow the sample to fall naturally into the measurement cell and to fill the cell, and to apply argon ion laser light (or semiconductor light) to the surface of the sample in the cell. This is performed by rotating the cell in a plane perpendicular to the laser beam while irradiating the cell with the laser beam. For the Raman spectrum obtained, 1580 cm
The intensity IA of the peak PA near ⁻¹ and the intensity IB of the peak PB near 1360 cm ⁻¹ are measured, and the intensity ratio R (R = IB / IA) is calculated. The Raman R value calculated by the measurement is defined as the Raman R value of the carbonaceous material of the present invention.

The above Raman measurement conditions are as follows.
・ Laser wavelength: Ar ion laser 514.5 nm (semiconductor laser 532 nm)
- Measuring ^range: 1100cm ^-1 ~1730cm -1
・ Raman R value: background processing,
・ Smoothing processing: Simple average, convolution 5 points (BET specific surface area)

BET specific surface area of the carbonaceous material is a value of the measured specific surface area using the BET method is usually 0.1 m ² · ^{g -1} or more, 0.7 m ² · ^{g -1} or more, 1. 0m ² · g ^−
1 or more is more preferable, and 1.5 m ² · g ⁻¹ or more is particularly preferable.
And a ² · ^{g -1} or less, preferably ^{25 m} 2 · ^{g -1} or less, ^{15 m} 2 · ^{g -1} and more preferably less, ^{10 m} 2 · ^{g -1} or less are especially preferred.

When the value of the BET specific surface area falls below this range, the lithium acceptability at the time of charging when used as a negative electrode material is liable to deteriorate, lithium is likely to precipitate on the electrode surface, and the stability may decrease. On the other hand, when it exceeds this range, when used as a negative electrode material, reactivity with a non-aqueous electrolyte solution increases, gas generation tends to increase, and a preferable battery may not be obtained.
The measurement of the specific surface area by the BET method is performed by preliminarily drying the sample at 350 ° C. for 15 minutes under a nitrogen flow using a surface area meter (for example, a fully automatic surface area measuring device manufactured by Okura Riken), and then measuring the atmospheric pressure. Using a nitrogen helium mixed gas precisely adjusted so that the value of the relative pressure of nitrogen is 0.3, the nitrogen adsorption BET one-point method by a gas flow method is used.

(Roundness)
When the circularity is measured as the degree of sphere of the carbonaceous material, it is preferable to fall within the following range. Note that the circularity is represented by “circularity = (perimeter of an equivalent circle having the same area as the particle projection shape) /
(The actual perimeter of the projected shape of the particle) ".
It is desirable that the circularity of the particles having a particle size of the carbonaceous material in the range of 3 to 40 μm is closer to 1;
Further, it is preferably at least 0.1, particularly preferably at least 0.5, more preferably at least 0.8, further preferably at least 0.85, particularly preferably at least 0.9. The high current density charge / discharge characteristics improve as the circularity increases. Therefore, when the circularity is lower than the above range, the filling property of the negative electrode active material is reduced, the resistance between the particles is increased, and the high-current density charge / discharge characteristics in a short time may be reduced.

The circularity is measured using a flow-type particle image analyzer (for example, FPIA manufactured by Sysmex Corporation). About 0.2 g of a sample is dispersed in a 0.2% by mass aqueous solution (about 50 mL) of a surfactant, polyoxyethylene (20) sorbitan monolaurate, and irradiated with 28 kHz ultrasonic waves at an output of 60 W for 1 minute. , The detection range is specified to be 0.6 to 400 μm, and the particle size is 3 to 4
It is measured for particles in the range of 0 μm.

The method for improving the degree of circularity is not particularly limited, but a method of performing spheroidization treatment to form a sphere is preferable because the shape of the interparticle gap when the electrode is formed is adjusted. Examples of the spheroidizing treatment include a method of mechanically approaching a spherical shape by applying a shear force and a compressive force, and a mechanical / physical treatment method of granulating a plurality of fine particles with a binder or the adhesive force of the particles themselves. Is mentioned.

(Tap density)
The tap density of the carbonaceous material is usually 0.1 g · cm ⁻³ or more, and 0.5 g · cm ^−3.
Or more, more preferably 0.7 g · cm ⁻³ or more, particularly preferably 1 g · cm ⁻³ or more, preferably 2 g · cm ⁻³ or less, more preferably 1.8 g · cm ⁻³ or less. Particularly preferred is 0.6 g · cm ⁻³ or less. When the tap density is lower than the above range, the packing density is difficult to increase when used as a negative electrode, and a high-capacity battery may not be obtained in some cases. On the other hand, if it exceeds the above range, voids between particles in the electrode become too small, and it becomes difficult to secure conductivity between particles, and it may be difficult to obtain favorable battery characteristics.
The tap density was measured by passing the sample through a 300 μm mesh sieve, dropping the sample into a 20 cm ³ tapping cell, filling the sample up to the upper end surface of the cell, and then measuring the powder density with a powder density meter (for example, manufactured by Seishin Enterprise Co., Ltd.). Tapping with a stroke length of 10 mm using a tap
Perform 0 times, and calculate the tap density from the volume at that time and the mass of the sample.

(Orientation ratio)
The orientation ratio of the carbonaceous material is usually 0.005 or more, preferably 0.01 or more,
It is more preferably 15 or more, and usually 0.67 or less. When the orientation ratio is below the above range, the high-density charge / discharge characteristics may be reduced. Note that the upper limit of the above range is the theoretical upper limit of the orientation ratio of the carbonaceous material.

The orientation ratio is measured by X-ray diffraction after forming a sample under pressure. 0.47 g of a sample with a diameter of 1
A molded body obtained by filling in a 7 mm molding machine and compressing at 58.8 MN · m ⁻² is set using clay to be flush with the surface of the sample holder for measurement, and X-ray diffraction is measured. . From the peak intensities of (110) diffraction and (004) diffraction of the obtained carbon, the (110) diffraction peak intensity / (
004) Calculate the ratio represented by the diffraction peak intensity.

The X-ray diffraction measurement conditions are as follows. “2θ” indicates a diffraction angle.
・ Target: Cu (Kα ray) graphite monochromator ・ Slit:
Divergence slit = 0.5 degree Light receiving slit = 0.15 mm
Scattering slit = 0.5 degree, measurement range and step angle / measurement time:
(110) plane: 75 degrees ≦ 2θ ≦ 80 degrees 1 degree / 60 seconds (004) plane: 52 degrees ≦ 2θ ≦ 57 degrees 1 degree / 60 seconds (aspect ratio (powder))
The aspect ratio of the carbonaceous material is usually 1 or more, and usually 10 or less, preferably 8 or less, more preferably 5 or less. If the aspect ratio exceeds the above range, streaking or uniform coating surface may not be obtained at the time of forming the electrode plate, and high current density charge / discharge characteristics may decrease. In addition,
The lower limit of the above range is the theoretical lower limit of the aspect ratio of the carbonaceous material.

The measurement of the aspect ratio is performed by observing the particles of the carbonaceous material under magnification with a scanning electron microscope. 50 arbitrary graphite particles fixed on the end face of the metal having a thickness of 50 μm or less are selected, and the stage on which the sample is fixed is rotated and tilted for each of the particles, and the carbonaceous material particles are observed three-dimensionally. Is measured, and the shortest diameter B orthogonal to the longest diameter A is measured, and the average value of A / B is obtained.

(Coverage)
The negative electrode active material of the present invention may be coated with a carbonaceous material or a graphite material. Among these, the coating with an amorphous carbonaceous material is preferable from the viewpoint of acceptability of lithium ions, and the coating rate is usually 0.5% or more and 30% or less, preferably 1% or more and 25% or less, more preferably. Is 2% or more and 20% or less. If this content is too large, the amorphous carbon portion of the negative electrode active material tends to increase, and the reversible capacity when the battery is assembled tends to decrease. If the content is too small,
Amorphous carbon sites are not uniformly coated on graphite particles serving as nuclei, strong granulation is not performed, and when crushed after firing, the particle size tends to be too small.

The content (coverage) of the carbide derived from the organic compound of the finally obtained negative electrode active material is as follows:
The amount can be calculated by the following equation based on the amount of the negative electrode active material, the amount of the organic compound, and the residual carbon ratio measured by a micro method according to JIS K 2270.
Formula: Coverage (%) of carbide derived from an organic compound = (mass of organic compound × residual carbon ratio × 100)
/ {Mass of negative electrode active material + (mass of organic compound x residual carbon ratio)}

(Internal porosity)
The internal porosity of the negative electrode active material is usually 1% or more, preferably 3% or more, more preferably 5% or more, and still more preferably 7% or more. Further, it is usually less than 50%, preferably 40% or less, more preferably 30% or less, and further preferably 20% or less. If the internal porosity is too small, the amount of liquid in the particles will decrease, and the charge / discharge characteristics will tend to deteriorate.If the internal porosity is too large, the interparticle gap will be small when the electrode is used, and the diffusion of the electrolyte will be reduced. Tends to be insufficient. In addition, a material that buffers expansion and contraction of metal particles that can be alloyed with Li, such as amorphous carbon or a graphite material, a resin, or the like, is filled in the voids or filled with the voids. It may be.

<Metal particles that can be alloyed with Li>
As a method for confirming that metal particles are metal particles that can be alloyed with Li,
Identification of the metal particle phase by X-ray diffraction, observation of the particle structure by an electron microscope and elemental analysis, elemental analysis by fluorescent X-ray, and the like are included.
As the metal particles that can be alloyed with Li, any conventionally known metal particles can be used.
g, Si, Sn, Al, Zr, Cr, P, S, V, Mn, Nb, Mo, Cu, Zn, Ge
, In, Ti and the like are preferred. Further, an alloy composed of two or more metals may be used, and the metal particles may be alloy particles formed of two or more metal elements. Among these, metals or compounds thereof selected from the group consisting of Si, Sn, As, Sb, Al, Zn and W are preferred.

Examples of the metal compound include a metal oxide, a metal nitride, and a metal carbide. Further, an alloy composed of two or more metals may be used.
Among them, Si or a Si compound is preferable in terms of increasing the capacity. In this specification, Si or a Si compound is collectively called a Si compound. As the Si compound, specifically, SiOx
, SiNx, SiCx, SiZxOy (Z = C, N), etc., and preferably SiOx when represented by a general formula. This general formula SiOx is composed of Si dioxide (SiO ₂ ) and metallic Si
(Si) as a raw material, and the value of x is usually 0 ≦ x <2. SiOx is
Compared to graphite, the theoretical capacity is large, and amorphous Si or nano-sized Si crystals can easily enter and exit alkali ions such as lithium ions, and can have a high capacity.

Specifically, it is represented as SiOx, wherein x is 0 ≦ x <2, more preferably 0.2 or more and 1.8 or less, further preferably 0.4 or more and 1.6 or less. Hereinafter, it is particularly preferably 0.6 or more and 1,4 or less, and X = 0 is particularly preferable. Within this range, the irreversible capacity due to the combination of Li and oxygen can be reduced at the same time as having a high capacity.

-Average particle diameter of metal particles that can be alloyed with Li (d50)
The average particle diameter (d50) of the metal particles that can be alloyed with Li is usually 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and still more preferably 0.3 μm, from the viewpoint of cycle life. It is usually at most 10 μm, preferably at most 9 μm, more preferably at most 8 μm. When the average particle size (d50) is within the above range, volume expansion due to charge / discharge is reduced, and good cycle characteristics can be obtained while maintaining charge / discharge capacity.

The average particle diameter (d50) is determined by a laser diffraction / scattering particle size distribution measuring method or the like.
BET specific surface area of metal particles that can be alloyed with Li The specific surface area of metal particles that can be alloyed with Li is usually 0.5 to 60 m ² / g by the BET method.
It is preferably from 1 to 40 m ² / g. When the specific surface area of the metal particles that can be alloyed with Li by the BET method is within the above range, the charge / discharge efficiency and discharge capacity of the battery are high, lithium can be taken in and out quickly at high speed charge / discharge, and the rate characteristics are excellent.

-Oxygen content of metal particles that can be alloyed with Li The oxygen content of metal particles that can be alloyed with Li is not particularly limited, but is usually 0.01 to 8% by mass and 0.05 to 5% by mass. Preferably, there is. The oxygen distribution state in the particle may be present near the surface, inside the particle, or uniformly present in the particle, but it is particularly preferably present near the surface. It is preferable that the oxygen content of the metal particles that can be alloyed with Li be within the above range, since the strong bond between Si and O suppresses volume expansion due to charge and discharge and has excellent cycle characteristics.

In the present invention, the negative electrode active material containing metal particles and graphite particles that can be alloyed with Li is Li
A mixture in which metal particles and graphite particles that can be alloyed with graphite particles may be mixed in a state of particles independent of each other, or a composite in which metal particles that can be alloyed with Li are present on the surface or inside of the graphite particles. Good. In this specification, the composite (also referred to as composite particle) is not particularly limited as long as it is a particle containing metal particles and a carbonaceous substance that can be alloyed with Li, but preferably, Li and an alloy The metal particles and the carbonaceous material are particles that are integrated by physical and / or chemical bonding. In a more preferred form, the metal particles and the carbonaceous material that can be alloyed with Li are present in a state in which each solid component is dispersed and present in the particles to the extent that they are present at least on both the surface of the composite particles and the inside of the bulk. In which carbonaceous material is present to integrate them by physical and / or chemical bonding. A more specific preferred form is a composite material composed of at least metal particles and graphite particles that can be alloyed with Li, wherein graphite particles, preferably natural graphite, have a folded structure having a curved surface. In addition, the negative electrode active material is characterized in that metal particles that can be alloyed with Li are present in gaps in the folded structure having the curved surface. In addition, the gap may be a void, or a substance that buffers expansion and contraction of metal particles that can be alloyed with Li, such as amorphous carbon, graphite, and resin, is present in the gap. Is also good.

-Content ratio of metal particles that can be alloyed with Li The content ratio of metal particles that can be alloyed with Li is 0.1% by mass or more, preferably 1% by mass, based on the total of the metal particles that can be alloyed with Li and the graphite particles. The content is at least 2% by mass, more preferably at least 2% by mass, further preferably at least 3% by mass, particularly preferably at least 5% by mass. Further, it is usually 99% by mass or less, preferably 50% by mass or less, more preferably 40% by mass or less, still more preferably 30% by mass or less, still more preferably 25% by mass or less, particularly preferably 15% or less, and most preferably. 10 mass% or less. This range is preferable because a sufficient capacity can be obtained.

The alloy-based negative electrode can be manufactured using any known method. Specifically, as a method for manufacturing the negative electrode, for example, a method in which the above-described negative electrode active material to which a binder or a conductive material is added is roll-formed as it is to form a sheet electrode, or a compression-formed pellet electrode is formed. Usually, the above negative electrode is formed on a current collector for the negative electrode (hereinafter sometimes referred to as a “negative electrode current collector”) by a coating method, a vapor deposition method, a sputtering method, a plating method, or the like. A method of forming a thin film layer (a negative electrode active material layer) containing an active material is used. In this case, a binder, a thickener, a conductive material, a solvent, etc. are added to the above-described negative electrode active material to form a slurry, which is applied to a negative electrode current collector, dried, and then pressed to increase the density. Then, a negative electrode active material layer is formed on the negative electrode current collector.

Examples of the material of the negative electrode current collector include steel, copper alloy, nickel, nickel alloy, and stainless steel. Among these, copper foil is preferred from the viewpoint of easy processing into a thin film and the cost.
The thickness of the negative electrode current collector is usually 1 μm or more, preferably 5 μm or more, and usually 100 μm
Or less, preferably 50 μm or less. If the thickness of the negative electrode current collector is too thick, the capacity of the whole battery may be too low, and if too thin, the handling may be difficult.

In order to improve the binding effect with the negative electrode active material layer formed on the surface, it is preferable that the surfaces of these negative electrode current collectors are previously subjected to a surface roughening treatment. Examples of the surface roughening method include blasting, rolling with a rough roll, polishing cloth paper with abrasive particles fixed thereon, a grindstone, emery buff,
A mechanical polishing method for polishing the surface of the current collector with a wire brush provided with a steel wire or the like, an electrolytic polishing method, a chemical polishing method, and the like can be given.

Further, in order to reduce the mass of the negative electrode current collector and improve the energy density per mass of the battery, a perforated negative electrode current collector such as an expanded metal or a punched metal may be used. By changing the aperture ratio of this type of negative electrode current collector, the mass can be changed to white. In addition, when a negative electrode active material layer is formed on both surfaces of this type of negative electrode current collector, peeling of the negative electrode active material layer is more unlikely to occur due to a rivet effect through this hole. However, if the aperture ratio is too high, the contact area between the negative electrode active material layer and the negative electrode current collector becomes small, so that the bonding strength may be lowered.

The slurry for forming the negative electrode active material layer is usually prepared by adding a binder, a thickener and the like to the negative electrode material. In this specification, the term “negative electrode material” refers to a material obtained by combining a negative electrode active material and a conductive material.
The content of the negative electrode active material in the negative electrode material is usually 70% by mass or more, particularly 75% by mass or more,
Further, it is usually preferably 97% by mass or less, particularly preferably 95% by mass or less. When the content of the negative electrode active material is too small, the capacity of the secondary battery using the obtained negative electrode tends to be insufficient, and when too large, the content of the conductive agent is relatively insufficient, so that the electric power as the negative electrode is reduced. It tends to be difficult to ensure conductivity. When two or more negative electrode active materials are used in combination, the total amount of the negative electrode active materials may satisfy the above range.

Examples of the conductive material used for the negative electrode include metal materials such as copper and nickel; and carbon materials such as graphite and carbon black. One of these may be used alone, or two or more thereof may be used in any combination and in any ratio. In particular, it is preferable to use a carbon material as the conductive material because the carbon material also functions as an active material. The content of the conductive material in the negative electrode material is usually at least 3% by mass, particularly at least 5% by mass, and usually at most 30% by mass, particularly preferably at most 25% by mass. If the content of the conductive material is too small, the conductivity tends to be insufficient. If the content is too large, the content of the negative electrode active material or the like tends to be relatively low, so that the battery capacity and strength tend to decrease. When two or more conductive materials are used in combination, the total amount of the conductive materials may satisfy the above range.

As the binder used for the negative electrode, any material can be used as long as it is a safe material for the solvent and the electrolyte used in the production of the electrode. Examples include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, styrene / butadiene rubber / isoprene rubber, butadiene rubber, ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer, and the like. One of these may be used alone, or two or more thereof may be used in any combination and in any ratio. The content of the binder is preferably at least 0.5 part by mass, particularly at least 1 part by mass, and usually at most 10 parts by mass, particularly preferably at most 8 parts by mass with respect to 100 parts by mass of the negative electrode material. If the content of the binder is too small, the strength of the obtained negative electrode tends to be insufficient, and if the content is too large, the content of the negative electrode active material or the like tends to be relatively small, so that the battery capacity or conductivity tends to be insufficient. It becomes. When two or more binders are used in combination, the total amount of the binders may satisfy the above range.

As the thickener used for the negative electrode, carboxymethylcellulose, methylcellulose,
Examples include hydroxymethylcellulose, ethylcellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, and casein. One of these may be used alone, or 2
Species or more may be used in any combination and in any ratio. The thickener may be used as needed, but when used, the content of the thickener in the negative electrode active material layer is usually 0.5% by mass.
Preferably, it is used in the range of 5% by mass or less.

The slurry for forming the negative electrode active material layer is prepared by mixing the above negative electrode active material with a conductive agent, a binder, and a thickener as necessary, and using an aqueous solvent or an organic solvent as a dispersion medium. You. As the aqueous solvent, water is usually used, and an organic solvent such as an alcohol such as ethanol and a cyclic amide such as N-methylpyrrolidone is used together in an amount of 30% by mass or less based on water. You can also. As the organic solvent, usually, cyclic amides such as N-methylpyrrolidone, linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide, and aromatic carbons such as anisole, toluene and xylene are usually used. Examples thereof include hydrogens, alcohols such as butanol and cyclohexanol, and among them, cyclic amides such as N-methylpyrrolidone and linear amides such as N, N-dimethylformamide and N, N-dimethylacetamide are preferable. . One of these may be used alone, or two or more of them may be used in any combination and in any ratio.
The obtained slurry is applied on the above-described negative electrode current collector, dried, and then pressed to form a negative electrode active material layer. The application method is not particularly limited, and a method known per se can be used. The method of drying is not particularly limited, and a known method such as natural drying, heating drying, and drying under reduced pressure can be used.

<Configuration of negative electrode and fabrication method>
Any known method can be used for manufacturing the electrode as long as the effects of the present invention are not significantly impaired. For example, a slurry is formed by adding a binder, a solvent, and, if necessary, a thickener, a conductive material, and a filler to the negative electrode active material, forming a slurry, applying the slurry to a current collector, drying, and then pressing the slurry. Can be.
When an alloy material is used, a vapor deposition method, a sputtering method, a plating method, or the like,
A method of forming a thin film layer (anode active material layer) containing the above-described anode active material is also used.

(Electrode density)
Although the electrode structure when the negative electrode active material is formed into an electrode is not particularly limited, the density of the negative electrode active material existing on the current collector is preferably 1 g · cm ⁻³ or more, and more preferably 1.2 g · cm ⁻³ or more. but more preferably, particularly preferably 1.3 g · ^{cm -3} or more, preferably 2.2 g · ^{cm -3} or less, more preferably 2.1 g · ^{cm -3} or less, 2.0 g · ^{cm -3} or less Further preferred is 1.9 g · cm ⁻³ or less. If the density of the negative electrode active material existing on the current collector exceeds the above range, the negative electrode active material particles will be destroyed, the initial irreversible capacity will increase, and the non-aqueous system near the current collector / negative electrode active material interface will be damaged. In some cases, high current density charge / discharge characteristics may be degraded due to a decrease in the permeability of the electrolytic solution. If the ratio is below the above range, the conductivity between the negative electrode active materials may decrease, the battery resistance may increase, and the capacity per unit volume may decrease.

2-2. Positive electrode <Positive electrode active material>
Hereinafter, the positive electrode active material (lithium transition metal-based compound) used for the positive electrode will be described.
<Lithium transition metal compound>
The lithium transition metal-based compound is a compound having a structure capable of removing and inserting Li ions, and examples thereof include a sulfide, a phosphate compound, and a lithium transition metal composite oxide. As the sulfide, a compound having a two-dimensional layered structure such as TiS ₂ or MoS ₂ or a strong tertiary tertiary compound represented by the general formula MexMo ₆ S ₈ (Me is various transition metals including Pb, Ag, and Cu) Chevrelle compounds having a primary skeleton structure are exemplified. Examples of the phosphate compound include those belonging to the olivine structure, and are generally represented by LiMePO ₄ (Me is at least one or more transition metals). Specifically, LiFePO ₄ , LiCoPO ₄
, LiNiPO ₄ , LiMnPO _{4 and the} like. Examples of the lithium transition metal composite oxide include those belonging to a spinel structure capable of three-dimensional diffusion and a layered structure capable of two-dimensional diffusion of lithium ions. Those having a spinel structure are generally LiMe
₂ O ₄ (Me is at least one transition metal), specifically, LiMn ₂ O ₄ ,
LiCoMnO ₄ , LiNi _0.5 Mn _1.5 O ₄ , LiCoVO _{4 and the} like.
Those having a layered structure are generally represented as LiMeO ₂ (Me is at least one or more transition metals). Specifically, LiCoO ₂ , LiNiO ₂ , LiNi _1-x Co _x O ₂ , L
_{iNi 1-x-y Co x} Mn y O 2, LiNi 0.5 Mn 0.5 O 2, Li 1.2 Cr 0
_{. 4} Mn _0.4 O ₂ , Li _1.2 Cr _0.4 Ti _0.4 O ₂ , LiMnO _{2 and the} like.

<composition>
The lithium-containing transition metal compound is, for example, a lithium transition metal-based compound represented by the following composition formula (A) or (B).
1) When the compound is a lithium transition metal compound represented by the following composition formula (A)
Li _{1 + x} MO ₂ ... (A)
However, x is usually 0 or more and 0.5 or less. M is Ni and Mn, or Ni, M
It is an element composed of n and Co, and the Mn / Ni molar ratio is usually 0.1 or more and 5 or less. The Ni / M molar ratio is usually 0 or more and 0.5 or less. The Co / M molar ratio is usually 0 or more,
. 5 or less. In some cases, the rich portion of Li represented by x is replaced with a transition metal site M.

In the composition formula (A), the atomic ratio of the oxygen content is described as 2 for convenience, but may have some non-stoichiometric property. Further, x in the above composition formula is a charged composition in the production stage of the lithium transition metal based compound. Normally, batteries on the market are aged after the batteries are assembled. Therefore, the amount of Li in the positive electrode may be deficient with charge and discharge. In that case, x in the case of discharging to 3 V may be measured to be -0.65 or more and 1 or less in composition analysis.

Further, the lithium transition metal-based compound obtained by firing at a high temperature in an oxygen-containing gas atmosphere in order to enhance the crystallinity of the positive electrode active material has excellent battery characteristics.
Further, the lithium transition metal-based compound represented by the composition formula (A) may be a solid solution with Li ₂ MO ₃ called a 213 layer as in the following general formula (A ′).
αLi ₂ MO _3. (1-α) LiM′O ₂ ... (A ′)
In the general formula, α is a number satisfying 0 <α <1.

M is at least one metal element having an average oxidation number of 4+, and specifically, Mn,
At least one metal element selected from the group consisting of Zr, Ti, Ru, Re and Pt.
M ′ is at least one metal element having an average oxidation number of 3+, preferably V,
Mn, Fe, at least one metal element selected from the group consisting of Co and Ni,
More preferably, it is at least one metal element selected from the group consisting of Mn, Co and Ni.

2) When the compound is a lithium transition metal-based compound represented by the following general formula (B).
Li [Li _{a Mb} Mn _2-ba ] O _{4 + δ} (B)
Here, M is an element composed of at least one of transition metals selected from Ni, Cr, Fe, Co, Cu, Zr, Al and Mg.
The value of b is usually 0.4 or more and 0.6 or less.
When the value of b is within this range, the energy density per unit mass of the lithium transition metal-based compound is high.

The value of a is usually 0 or more and 0.3 or less. In addition, a in the above composition formula is a charged composition in the production stage of the lithium transition metal-based compound. Normally, batteries on the market are aged after the batteries are assembled. Therefore, the amount of Li in the positive electrode may be deficient with charge and discharge. In that case, a in the case of discharging to 3 V is -0.65 in the composition analysis.
Above, it may be measured to 1 or less.

When the value of a is within this range, the energy density per unit mass of the lithium transition metal compound is not significantly impaired, and good load characteristics can be obtained.
Further, the value of δ is usually in the range of ± 0.5.
When the value of δ is within this range, the stability as a crystal structure is high, and the cycle characteristics and high-temperature storage of a battery having an electrode manufactured using this lithium transition metal-based compound are good.

Here, the chemical meaning of the lithium composition in the lithium-nickel-manganese-based composite oxide which is the composition of the lithium transition metal-based compound will be described in more detail below.
In order to obtain a and b in the composition formula of the lithium transition metal-based compound, each transition metal and lithium are analyzed by an inductively coupled plasma emission spectrometer (ICP-AES) to obtain Li / Ni / Mn.
It is calculated by calculating the ratio of

From a structural point of view, it is considered that the lithium related to a is substituted into the same transition metal site. Here, the average valence of M and manganese becomes larger than 3.5 due to the principle of charge neutrality due to lithium according to a.
Further, the lithium transition metal-based compound may be substituted by fluorine, and may be LiMn ₂ O
_{Notated as 4-x} F _2x .

<blend>
Specific examples of the lithium transition metal-based compound having the above composition include, for example, Li _{1 + x} Ni _{0
. 5} Mn _0.5 O ₂ , Li _{1 + x} Ni _0.85 Co _0.10 Al _0.05 O ₂ , Li _{1+
x Ni 0.33 Mn 0.33 Co 0.33 O} 2, Li 1 + x Ni 0.45 Mn 0.45 C
o _0.1 O ₂ , Li _{1 + x} Mn _1.8 Al _0.2 O ₄ , Li _{1 + x} Mn _1.5 Ni _0.5
O _{4 and the} like. These lithium transition metal compounds may be used alone or in a combination of two or more.

<Introduction of foreign elements>
Further, a foreign element may be introduced into the lithium transition metal-based compound. As a different element, B
, Na, Mg, Al, K, Ca, Ti, V, Cr, Fe, Cu, Zn, Sr, Y, Zr,
Nb, Ru, Rh, Pd, Ag, In, Sb, Te, Ba, Ta, Mo, W, Re, Os
, Ir, Pt, Au, Pb, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy,
Ho, Er, Tm, Yb, Lu, Bi, N, F, S, Cl, Br, I, As, Ge, P,
It is selected from one or more of Pb, Sb, Si and Sn. These foreign elements are
It may be incorporated in the crystal structure of the lithium transition metal-based compound, or may not be incorporated in the crystal structure of the lithium transition metal-based compound, and may be unevenly distributed as a simple substance or a compound on the particle surface or crystal grain boundary. Good.

[Positive electrode for lithium secondary battery]
The positive electrode for a lithium secondary battery is obtained by forming a positive electrode active material layer containing the above-described lithium transition metal-based compound powder for a lithium secondary battery positive electrode material and a binder on a current collector.
The positive electrode active material layer is usually formed by mixing a positive electrode material, a binder, and, if necessary, a conductive material and a thickening agent, etc., in a dry manner into a sheet and pressing it on a positive electrode current collector. Alternatively, these materials are prepared by dissolving or dispersing them in a liquid medium to form a slurry, applying the slurry to a positive electrode current collector, and drying.

As the material of the positive electrode current collector, a metal material such as aluminum, stainless steel, nickel plating, titanium, and tantalum, and a carbon material such as carbon cloth and carbon paper are usually used. In the case of a metal material, a metal foil, a metal cylinder, a metal coil, a metal plate, a metal thin film, an expanded metal, a punched metal, a foamed metal, etc., and in the case of a carbon material, a carbon plate, a carbon thin film, a carbon cylinder And the like. Note that the thin film may be appropriately formed in a mesh shape.
When a thin film is used as the positive electrode current collector, its thickness is arbitrary, but is usually 1 μm or more.
A range of 00 mm or less is preferred. When the thickness is smaller than the above range, the strength required as a current collector may be insufficient, while when the thickness is larger than the above range, handleability may be impaired.

The binder used in the production of the positive electrode active material layer is not particularly limited, and in the case of a coating method, any material may be used as long as it is a material that is stable with respect to the liquid medium used in the production of the electrode. Resin-based polymers such as polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, cellulose, nitrocellulose, SBR (styrene / butadiene rubber), NBR (acrylonitrile / butadiene rubber), fluorine rubber, isoprene rubber, butadiene rubber, ethylene Rubbery polymers such as propylene rubber, styrene / butadiene / styrene block copolymers and hydrogenated products thereof, EPDM (ethylene / propylene / diene terpolymer), styrene / ethylene / butadiene / ethylene copolymer, Styrene / isoprene styrene bronze Thermoplastic elastomeric polymers such as copolymers and their hydrogenated products, syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer, etc. Ion conductivity of flexible resinous polymers, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polymers such as fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymer, and alkali metal ions (particularly lithium ions) And the like. One of these substances may be used alone, or two or more of them may be used in any combination and in any ratio.

The ratio of the binder in the positive electrode active material layer is usually 0.1% by mass or more and 80% by mass or less. When the ratio of the binder is too low, the mechanical strength of the positive electrode is insufficient because the positive electrode active material cannot be sufficiently retained, and the battery performance such as cycle characteristics may be deteriorated. It may lead to a decrease in battery capacity and conductivity.
The positive electrode active material layer usually contains a conductive material to increase conductivity. Although there is no particular limitation on the type, specific examples include metal materials such as copper and nickel, graphite (graphite) such as natural graphite and artificial graphite, carbon black such as acetylene black, and amorphous carbon such as needle coke. And the like. One of these substances may be used alone, or two or more of them may be used in any combination and in any ratio. The ratio of the conductive material in the positive electrode active material layer is usually 0.01% by mass or more and 50% by mass or less. If the proportion of the conductive material is too low, the conductivity may be insufficient, and if it is too high, the battery capacity may decrease.

As a liquid medium for forming a slurry, it is possible to dissolve or disperse a lithium transition metal-based compound powder as a positive electrode material, a binder, and a conductive material and a thickener used as necessary. As long as it is a solvent, the type thereof is not particularly limited, and either an aqueous solvent or an organic solvent may be used. Examples of aqueous solvents include water, alcohols, and the like. Examples of organic solvents include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methylethylketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N , N-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran (THF), toluene, acetone, dimethylether, dimethylacetamide, hexamethylphosphalamide, dimethylsulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane and the like. be able to. In particular, when an aqueous solvent is used, a dispersant is added in addition to the thickener, and a slurry is formed using a latex such as SBR. In addition,
One of these solvents may be used alone, or two or more thereof may be used in an optional combination and ratio.

The content ratio of the lithium transition metal-based compound powder as the positive electrode material in the positive electrode active material layer is usually 10% by mass or more and 99.9% by mass or less. If the ratio of the lithium transition metal-based compound powder in the positive electrode active material layer is too large, the strength of the positive electrode tends to be insufficient, and if it is too small, the capacity may be insufficient.
The thickness of the positive electrode active material layer is usually about 10 to 200 μm.

The electrode density of the positive electrode after pressing is usually 2.2 g / cm ³ or more and 4.2 g / cm ³
It is as follows.
The positive electrode active material layer obtained by coating and drying is preferably compacted by a roller press or the like in order to increase the packing density of the positive electrode active material.
Thus, a positive electrode for a lithium secondary battery can be prepared.

2-3. Separator A separator is usually interposed between the positive electrode and the negative electrode to prevent a short circuit. In this case, the non-aqueous electrolyte of the present invention is usually used by impregnating the separator.
The material and shape of the separator are not particularly limited, and any known material can be used as long as the effects of the present invention are not significantly impaired. Among them, a resin, a glass fiber, an inorganic substance, or the like, which is formed of a material that is stable with respect to the nonaqueous electrolytic solution of the present invention, is used. Is preferred.

As the material of the resin and the glass fiber separator, for example, polyolefin such as polyethylene and polypropylene, aromatic polyamide, polytetrafluoroethylene, polyether sulfone, a glass filter and the like can be used. Among them, glass filters and polyolefins are preferred, and polyolefins are more preferred. One of these materials may be used alone, or two or more thereof may be used in any combination and in any ratio.

The thickness of the separator is arbitrary, but is usually 1 μm or more, preferably 5 μm or more,
It is more preferably 0 μm or more, and usually 50 μm or less, preferably 40 μm or less, and more preferably 30 μm or less. If the separator is too thin than the above range, the insulation and the mechanical strength may decrease. If the thickness is more than the above range, not only may the battery performance such as rate characteristics decrease, but also the energy density of the whole non-aqueous electrolyte secondary battery may decrease.

Further, when a porous material such as a porous sheet or a nonwoven fabric is used as the separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, and more preferably 45%.
More preferably, it is 90% or less, usually 85% or less, more preferably 75% or less. When the porosity is smaller than the above range, the film resistance tends to increase and the rate characteristics tend to deteriorate. On the other hand, when it is larger than the above range, the mechanical strength of the separator tends to decrease, and the insulating property tends to decrease.

The average pore diameter of the separator is also arbitrary, but is usually 0.5 μm or less, and 0.2 μm
The following is preferable, and it is usually 0.05 μm or more. If the average pore diameter exceeds the above range, a short circuit is likely to occur. On the other hand, if the ratio is below the above range, the film resistance may increase and the rate characteristics may decrease.
On the other hand, examples of the inorganic material include oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate. Used.

As the form, a thin film such as a nonwoven fabric, a woven fabric, or a microporous film is used. In the case of a thin film, those having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm are preferably used.
In addition to the above-mentioned independent thin film shape, a separator obtained by forming a composite porous layer containing the inorganic particles on the surface layer of the positive electrode and / or the negative electrode using a resin binder may be used. For example, a porous layer may be formed on both surfaces of the positive electrode using alumina particles having a 90% particle size of less than 1 μm and a fluororesin as a binder.

The characteristics of the separator in the non-electrolyte secondary battery can be grasped by the Gurley value. The Gurley value indicates the difficulty in passing air in the thickness direction of the film, and is represented by the number of seconds required for 100 ml of air to pass through the film. Means it is harder to get through. That is, a smaller value means better communication in the thickness direction of the film, and a larger value means poor communication in the thickness direction of the film. The continuity is the degree of connection of the holes in the film thickness direction. If the Gurley value of the separator of the present invention is low, it can be used for various applications. For example, when used as a separator for non-aqueous lithium secondary batteries, low Gurley value means that
This means that lithium ions can easily move, and is preferable because of excellent battery performance. The Gurley value of the separator is arbitrary, but is preferably 10 to 1000 seconds / 100 ml, more preferably 15 to 800 seconds / 100 ml, and still more preferably 20 to 500 seconds / 100 ml.
100 ml. When the Gurley value is 1000 seconds / 100 ml or less, the electric resistance is substantially low, and the separator is preferable.

2-4. Battery design <Electrode group>
The electrode group has a laminated structure in which the positive electrode plate and the negative electrode plate are disposed with the separator interposed therebetween,
Alternatively, any of those having a structure in which the positive electrode plate and the negative electrode plate are spirally wound with the separator interposed therebetween may be used. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupancy) is usually 40% or more, preferably 50% or more, and usually 90% or less.
80% or less is preferable.

If the electrode group occupancy is below the above range, the battery capacity will decrease. If the above range is exceeded, the void space is small, and as the battery becomes hot, the members expand or the vapor pressure of the liquid component of the electrolyte increases, and the internal pressure rises. In some cases, a gas release valve that lowers various characteristics such as high temperature and high-temperature storage, or that releases internal pressure to the outside is operated.

<Outer case>
The material of the outer case is not particularly limited as long as it is a substance that is stable with respect to the nonaqueous electrolyte used. Specifically, a metal such as a nickel-plated steel plate, stainless steel, aluminum or an aluminum alloy, a magnesium alloy, or a laminated film (laminated film) of a resin and an aluminum foil is used. From the viewpoint of weight reduction, a metal of aluminum or an aluminum alloy or a laminate film is suitably used.

In an outer case using metals, a metal is welded to each other by laser welding, resistance welding, or ultrasonic welding to form a sealed hermetic structure, or a caulking structure using the above metals via a resin gasket. Things. As the outer case using the above-mentioned laminated film, a case in which a resin layer is heat-sealed to form a hermetically sealed structure may be used. In order to improve the sealing property, a resin different from the resin used for the laminate film may be interposed between the resin layers. In particular, when a resin layer is heat-sealed through a current collecting terminal to form a hermetically sealed structure, the metal and the resin are joined together. Resins are preferably used.

<Protective element>
As a protection element, PTC (Posit) whose resistance increases when abnormal heat generation or excessive current flows
For example, an active temperature coefficient, a temperature fuse, a thermistor, or a valve (current cutoff valve) that shuts off a current flowing through a circuit due to a sudden increase in battery internal pressure or internal temperature when abnormal heat is generated can be used. It is preferable to select a protection element that does not operate under normal use of a high current, and it is more preferable that the protection element is designed not to cause abnormal heat generation or thermal runaway without the protection element.

(Exterior)
The non-aqueous electrolyte secondary battery of the present invention is usually configured by housing the above-described non-aqueous electrolyte, negative electrode, positive electrode, separator, and the like in an exterior body (exterior case). There is no limitation on this exterior body, and any known one can be adopted as long as the effects of the present invention are not significantly impaired.
The material of the outer case is not particularly limited as long as it is a substance that is stable with respect to the non-aqueous electrolyte used. Specifically, a nickel-plated steel plate, a metal such as stainless steel, aluminum or an aluminum alloy, a magnesium alloy, nickel, titanium, or the like, or a laminated film (laminated film) of a resin and an aluminum foil is used. From the viewpoint of weight reduction, a metal of aluminum or an aluminum alloy or a laminate film is suitably used.

In the outer case using the above-mentioned metals, a metal is welded by laser welding, resistance welding, ultrasonic welding to form a sealed hermetic structure, or a caulked structure using the above-mentioned metals via a resin gasket. To do. As the outer case using the above-mentioned laminated film, a case in which a resin layer is heat-sealed to form a hermetically sealed structure may be used. In order to improve the sealing property, a resin different from the resin used for the laminate film may be interposed between the resin layers. In particular, when a resin layer is heat-sealed through a current collecting terminal to form a hermetically sealed structure, the metal and the resin are joined together. Resins are preferably used.

The shape of the outer case is also arbitrary, and may be, for example, any of a cylindrical shape, a square shape, a laminate type, a coin shape, and a large size.
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
Compounds having a structure represented by the general formula (A) used in this example are shown below.

<Examples 1-1 to 1-2, 1-5 to 1-7, Comparative examples 1-1 to 1-8>
[Preparation of non-aqueous electrolyte]
Under a dry argon atmosphere, 1 mol / L of a sufficiently dried LiPF ₆ (as a concentration in a non-aqueous electrolyte) was added to a mixture of monofluoroethylene carbonate and ethyl methyl carbonate (EMC) (volume capacity ratio 2: 8). ) Was dissolved (this is referred to as reference electrolyte 1). Compounds were added to the entire reference electrolyte solution 1 at the ratios shown in Table 1 below to prepare an electrolyte solution. However, Comparative Example 1-1 is the reference electrolyte 1 itself.

[Preparation of positive electrode]
94% by mass of lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, 3% by mass of acetylene black as a conductive material, and 3% by mass of polyvinylidene fluoride (PVdF) as a binder
Were mixed with a disperser in an N-methylpyrrolidone solvent to form a slurry. This was uniformly applied on both sides of an aluminum foil having a thickness of 21 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
As the negative electrode active material, a silicon powder and a graphite powder were mixed with a binder, an N-methylpyrrolidone solution was added thereto, and mixed with a disperser to form a slurry. The obtained slurry was uniformly coated on a copper foil having a thickness of 20 μm as a negative electrode current collector to form a negative electrode, and the active material was cut out to have a width of 30 mm and a length of 40 mm to obtain a negative electrode. The negative electrode is 60 degrees Celsius.
And dried under reduced pressure for 12 hours.

[Manufacture of non-aqueous electrolyte battery (laminated type)]
The above positive electrode, negative electrode, and polyolefin separator were laminated in the order of negative electrode, separator, and positive electrode. Wrap the battery element thus obtained in an aluminum laminate film,
After injecting an electrolytic solution described later, it was vacuum-sealed to produce a sheet-like nonaqueous electrolytic solution secondary battery.

<Evaluation of non-aqueous electrolyte secondary battery>
[High temperature cycle test]
After charging the non-aqueous electrolyte secondary battery of coin type cell at a constant current of 0.05 C for 4 hours in a constant temperature bath of 25 ° C. (hereinafter, appropriately referred to as “CC charging”), the battery was charged at 0.2 C for 4 hours. Constant current-constant voltage charging (hereinafter, appropriately referred to as “CC-CV charging”) was performed up to 0.0 V. Then 0.2
Discharged to 2.75 V at C. Then, after CC-CV to 4.0V at 0.2C, 0.2
The battery was discharged to 2.75 V at C to stabilize the non-aqueous electrolyte secondary battery. After that, 4 at 0.2C
. After performing CC-CV charge to 2V, it discharged to 2.75V at 0.2C and performed initial conditioning.

The cell after the initial conditioning is placed in a 45 ° C constant temperature bath at 0.5 C to 4.2 V CCC.
After charging the battery to V, the process of discharging the battery to 2.75 V at a constant current of 0.5 C is defined as one cycle.
00 cycles were performed. The capacity at the 200th cycle was defined as “capacity after 200 cycles”. Here, 1C represents a current value at which the reference capacity of the battery is discharged in one hour, and for example, 0.2C represents a current value which is 1/5 of that.

  Table 1 below shows the capacity after 200 cycles, normalized by the value of Comparative Example 1-1.

<Examples 2-1 to 2-3, Comparative Examples 2-1 to 2-4>
[Preparation of non-aqueous electrolyte]
Under a dry argon atmosphere, a mixture of the compound (g) and EMC in the ratio shown in Table 2 below was added to a mixture of:
1 mol / L (as the concentration in the non-aqueous electrolyte) of the sufficiently dried LiPF ₆ was dissolved.
On the other hand, compounds were added at the ratios shown in Table 2 below to prepare an electrolytic solution.

[Preparation of positive electrode]
97% by mass of lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, 1.5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) as a binder 1.
5% by mass was mixed in an N-methylpyrrolidone solvent with a disperser to form a slurry. This was uniformly applied on both sides of an aluminum foil having a thickness of 21 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
100 parts by mass of graphite powder as a negative electrode active material, 1 part by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and 1 part by mass of an aqueous dispersion of styrene-butadiene rubber, respectively, as a thickener and a binder 1 part by mass (concentration of styrene-butadiene rubber: 50% by mass) was added and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a copper foil having a thickness of 12 μm, dried, and then pressed to obtain a negative electrode.

[Manufacture of non-aqueous electrolyte battery (coin type)]
Using the above positive electrode and negative electrode, and the non-aqueous electrolyte solutions prepared in Examples and Comparative Examples, a coin-type cell was produced in the following procedure. That is, the positive electrode was accommodated in a stainless steel can that also serves as the positive electrode conductor, and the negative electrode was placed thereon via a polyethylene separator impregnated with an electrolytic solution. The can body and the sealing plate also serving as the negative electrode conductor were caulked and sealed via an insulating gasket to produce a coin cell.

[Battery evaluation]
After a non-aqueous electrolyte secondary battery of coin type cell was charged at a constant current of 0.05 C for 6 hours in a constant temperature bath of 25 ° C. (hereinafter, referred to as “CC charging” as appropriate), the battery was charged at 0.2 C for 3 hours. The battery was discharged to 0.000 V, and the obtained capacity was [discharge capacity] / [charge capacity], and the value obtained was defined as the initial efficiency. Constant current-constant voltage charging up to 4.1V at 0.2C (hereinafter referred to as "CC-CV charging" as appropriate)
Was done. Thereafter, the battery was discharged to 3.00 V at 0.2 C to stabilize the non-aqueous electrolyte secondary battery. Then, after performing CC-CV charging to 4.33V at 0.2C, 3.00 at 0.2C.
The operation of discharging to V was performed three times, and the third discharge capacity was set to “0.2 C capacity”. here,
1C represents a current value at which the reference capacity of the battery is discharged in one hour.
/ 5.

[Evaluation of high-temperature storage characteristics]
The non-aqueous electrolyte battery after the initial capacity evaluation was performed at 25 ° C. and 4.3 C at 0.2 C.
After performing CC-CV charging (0.05 C cut) up to V, high-temperature storage was performed at 85 ° C. for 24 hours. After the battery was sufficiently cooled, the battery was discharged at 25 ° C. at 0.2 C to 3 V to obtain a capacity after the evaluation of high-temperature storage characteristics, which was defined as “remaining capacity after high-temperature storage”.
Table 2 below shows the initial efficiency, the 0.2 C capacity, and the remaining capacity after the high-temperature storage test, normalized by the values of Comparative Example 2-1.

When Examples 2-1 to 2-3 and Comparative Example 2-1 are compared, when the content of the compound (g) with respect to the electrolytic solution is 50% by mass or less, it is compared with Comparative Example 2-1 which exceeds 50% by mass. It can be seen that the initial efficiency is improved. Paying attention to Comparative Example 2-2, it is important to include a specific amount of the compound (g) in the electrolytic solution since the characteristics are not as good as those of Examples 2-1 to 2-3 unless the compound (g) is contained. It can be seen that it is. Further, the compounds (a) and (
Even if g) is used alone, both the initial efficiency and the initial capacity are lower than those of Example 2-1. Therefore, it can be seen that the co-addition of the compound (a) and the compound (g) greatly improves the properties. The same can be said for the remaining capacity after the high-temperature storage test.

<Examples 3-A-1 to 3-A-15, Comparative Examples 3-A-1 to 3-A-5>
[Preparation of non-aqueous electrolyte]
In a dry argon atmosphere, 1 mol / L (as a concentration in a non-aqueous electrolyte) of sufficiently dried LiPF ₆ is dissolved in a mixture of ethylene carbonate and diethyl carbonate (DEC) (volume-volume ratio of 3: 7). Further, 2.0 mass% of each of vinylene carbonate (VC) and fluoroethylene carbonate was added (this is referred to as a reference electrolyte 3-A). Compounds were added to the entire reference electrolyte solution 3 at the ratios shown in Table 3 below to prepare an electrolyte solution. However, Comparative Example 3-A-1 is the reference electrolyte 3-A itself.

[Preparation of positive electrode]
Lithium-nickel-cobalt-manganese composite oxide (NMC) 85 as positive electrode active material
A mass%, acetylene black 10 mass% as a conductive material, and polyvinylidene fluoride (PVdF) 5 mass% as a binder were mixed in an N-methylpyrrolidone solvent with a disperser to form a slurry. This was uniformly applied on both sides of an aluminum foil having a thickness of 21 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
50 g of Si fine particles having an average particle diameter of 0.2 μm are converted into 2000 g of flaky graphite having an average particle diameter of 35 μm.
The mixture was dispersed in the apparatus, charged into a hybridization system (manufactured by Nara Machinery Co., Ltd.), and circulated or retained in the apparatus at a rotor rotation speed of 7000 rpm for 180 seconds to be processed to obtain a composite of Si and graphite particles. The obtained composite was mixed with coal tar pitch as an organic compound to be a carbonaceous material so that the coverage after firing was 7.5%, and kneaded and dispersed by a biaxial kneader. The resulting dispersion was introduced into a firing furnace and fired at 1000 ° C. for 3 hours in a nitrogen atmosphere. The obtained fired product was further pulverized by a hammer mill and then sieved (45 μm) to prepare a negative electrode active material. The content of the silicon element, the average particle diameter d50, the tap density, and the specific surface area measured by the above measurement method were 2.0% by mass, 20 μm, 1.0 g / cm ³ , and 7.2 m ² / g, respectively. .

97.5 parts by mass of the negative electrode active material, 1 part by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and 1 part by mass of a styrene-butadiene rubber as a thickener and a binder, respectively.
1.5 parts by mass of a styrene-butadiene rubber (concentration of 50% by mass) was added, and mixed with a disperser to form a slurry. This slurry was uniformly applied to one surface of a copper foil having a thickness of 10 μm, dried, and then pressed to obtain a negative electrode.

[Manufacture of non-aqueous electrolyte battery (laminated type)]
The above positive electrode, negative electrode, and polyolefin separator were laminated in the order of negative electrode, separator, and positive electrode. Wrap the battery element thus obtained in an aluminum laminate film,
After injecting an electrolytic solution described later, it was vacuum-sealed to produce a sheet-like nonaqueous electrolytic solution secondary battery.

<Evaluation of non-aqueous electrolyte secondary battery>
[High temperature cycle test]
In a constant temperature bath at 25 ° C., the nonaqueous electrolyte secondary battery of the laminate type cell was charged at a constant current-constant voltage up to 4.0 V with a current corresponding to 0.05 C. Thereafter, the battery was discharged at 0.05 C to 2.5 V. Then, after performing CC-CV to 4.0V at 0.2C, it discharged to 2.5V at 0.2C and stabilized the non-aqueous electrolyte secondary battery. Then, after performing CC-CV charge to 4.2V at 0.2C, it discharged to 2.5V at 0.2C and performed initial conditioning.

The cell after the initial conditioning is placed in a 45 ° C constant temperature bath at 0.5 C to 4.2 V CCC.
After charging the battery to V, the process of discharging the battery to 2.5 V at a constant current of 0.5 C is defined as one cycle.
0 cycles were performed. The capacity at the 100th cycle was defined as “capacity after 100 cycles”. The thickness of the battery before and after the cycle was measured. The change in thickness of the battery due to the cycle was defined as “battery swelling”.
Table 3 below shows the capacity and battery swelling after 100 cycles, normalized by the values of Comparative Example 3-A-1.

<Examples 3-B-1 to 3-B-2, Comparative Examples 3-B-1 to 3-B-3>
[Preparation of non-aqueous electrolyte]
In a dry argon atmosphere, 1 mol / L (as a concentration in a non-aqueous electrolyte) of sufficiently dried LiPF ₆ is dissolved in a mixture of ethylene carbonate and diethyl carbonate (DEC) (volume-volume ratio of 3: 7). (This is referred to as reference electrolyte 3-B). Compounds were added to the entire reference electrolyte solution 3-B at the ratios shown in Table 4 below to prepare electrolyte solutions. However, Comparative Example 3-B-1 is the reference electrolyte 3-B itself.

[Preparation of positive electrode]
Lithium-nickel-cobalt-manganese composite oxide (NMC) 85 as positive electrode active material
A mass%, acetylene black 10 mass% as a conductive material, and polyvinylidene fluoride (PVdF) 5 mass% as a binder were mixed in an N-methylpyrrolidone solvent with a disperser to form a slurry. This was uniformly applied on both sides of an aluminum foil having a thickness of 21 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
50 g of Si fine particles having an average particle diameter of 0.2 μm are converted into 2000 g of flaky graphite having an average particle diameter of 35 μm.
The mixture was dispersed in the apparatus, charged into a hybridization system (manufactured by Nara Machinery Co., Ltd.), and circulated or retained in the apparatus at a rotor rotation speed of 7000 rpm for 180 seconds to be processed to obtain a composite of Si and graphite particles. The obtained composite was mixed with coal tar pitch as an organic compound to be a carbonaceous material so that the coverage after firing was 7.5%, and kneaded and dispersed by a biaxial kneader. The obtained dispersion was introduced into a firing furnace and fired at 1000 ° C. for 3 hours in a nitrogen atmosphere. The obtained fired product was further pulverized by a hammer mill and then sieved (45 μm) to prepare a negative electrode active material. The content of the silicon element, the average particle diameter d50, the tap density, and the specific surface area measured by the above measurement method were 2.0% by mass, 20 μm, 1.0 g / cm ³ , and 7.2 m ² / g, respectively. .

97.5 parts by mass of the negative electrode active material, 1 part by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and 1 part by mass of a styrene-butadiene rubber as a thickener and a binder, respectively.
1.5 parts by mass of a styrene-butadiene rubber (concentration of 50% by mass) was added, and mixed with a disperser to form a slurry. This slurry was uniformly applied to one surface of a copper foil having a thickness of 10 μm, dried, and then pressed to obtain a negative electrode.

[Manufacture of non-aqueous electrolyte battery (laminated type)]
The above positive electrode, negative electrode, and polyolefin separator were laminated in the order of negative electrode, separator, and positive electrode. Wrap the battery element thus obtained in an aluminum laminate film,
After injecting an electrolytic solution described later, it was vacuum-sealed to produce a sheet-like nonaqueous electrolytic solution secondary battery.

<Evaluation of non-aqueous electrolyte secondary battery>
[High temperature cycle test]
In a constant temperature bath at 25 ° C., the nonaqueous electrolyte secondary battery of the laminate type cell was charged at a constant current-constant voltage up to 4.0 V with a current corresponding to 0.05 C. Thereafter, the battery was discharged at 0.05 C to 2.5 V. Then, after performing CC-CV to 4.0V at 0.2C, it discharged to 2.5V at 0.2C and stabilized the non-aqueous electrolyte secondary battery. Then, after performing CC-CV charge to 4.2V at 0.2C, it discharged to 2.5V at 0.2C and performed initial conditioning.

The cell after the initial conditioning is placed in a 45 ° C constant temperature bath at 0.5 C to 4.2 V CCC.
After charging the battery to V, the process of discharging the battery to 2.5 V at a constant current of 0.5 C is defined as one cycle.
0 cycles were performed. The capacity at the 100th cycle was defined as “capacity after 100 cycles”. The thickness of the battery before and after the cycle was measured. The change in thickness of the battery due to the cycle was defined as “battery swelling”.
Table 4 below shows the capacity and battery swelling after 100 cycles, normalized by the values of Comparative Example 3-B-1.

<Examples 4-1 to 4-7, Comparative examples 4-1 to 4-3>
[Preparation of non-aqueous electrolyte]
In a dry argon atmosphere, 1 mol / L (as a concentration in a non-aqueous electrolyte) of sufficiently dried LiPF ₆ is dissolved in a mixture of ethylene carbonate and diethyl carbonate (DEC) (volume-volume ratio of 3: 7). Further, 2.0 mass% of each of vinylene carbonate (VC) and fluoroethylene carbonate was added (this is referred to as reference electrolyte 4). Compounds were added to the entire reference electrolyte solution 4 at the ratios shown in Table 5 below to prepare an electrolyte solution. However, Comparative Example 4-1 is the reference electrolyte 4 itself.

[Preparation of positive electrode]
Lithium-nickel-cobalt-manganese composite oxide (NMC) 85 as positive electrode active material
A mass%, acetylene black 10 mass% as a conductive material, and polyvinylidene fluoride (PVdF) 5 mass% as a binder were mixed in an N-methylpyrrolidone solvent with a disperser to form a slurry. This was uniformly applied on both sides of an aluminum foil having a thickness of 21 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
50 g of Si fine particles having an average particle diameter of 0.2 μm are converted into 2000 g of flaky graphite having an average particle diameter of 35 μm.
The mixture was dispersed in the apparatus, charged into a hybridization system (manufactured by Nara Machinery Co., Ltd.), and circulated or retained in the apparatus at a rotor rotation speed of 7000 rpm for 180 seconds to be processed to obtain a composite of Si and graphite particles. The obtained composite was mixed with coal tar pitch as an organic compound to be a carbonaceous material so that the coverage after firing was 7.5%, and kneaded and dispersed by a biaxial kneader. The resulting dispersion was introduced into a firing furnace and fired at 1000 ° C. for 3 hours in a nitrogen atmosphere. The obtained fired product was further pulverized by a hammer mill and then sieved (45 μm) to prepare a negative electrode active material. The content of the silicon element, the average particle diameter d50, the tap density, and the specific surface area measured by the above measurement method were 2.0% by mass, 20 μm, 1.0 g / cm ³ , and 7.2 m ² / g, respectively. .

97.5 parts by mass of the negative electrode active material, 1 part by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and 1 part by mass of a styrene-butadiene rubber as a thickener and a binder, respectively.
1.5 parts by mass of a styrene-butadiene rubber (concentration of 50% by mass) was added, and mixed with a disperser to form a slurry. This slurry was uniformly applied to one surface of a copper foil having a thickness of 10 μm, dried, and then pressed to obtain a negative electrode.

[Manufacture of non-aqueous electrolyte battery (laminated type)]
The above positive electrode, negative electrode, and polyolefin separator were laminated in the order of negative electrode, separator, and positive electrode. Wrap the battery element thus obtained in an aluminum laminate film,
After injecting an electrolytic solution described later, it was vacuum-sealed to produce a sheet-like nonaqueous electrolytic solution secondary battery.

<Evaluation of non-aqueous electrolyte secondary battery>
[High temperature storage test]
In a constant temperature bath at 25 ° C., the nonaqueous electrolyte secondary battery of the laminate type cell was charged at a constant current-constant voltage up to 4.0 V with a current corresponding to 0.05 C. Thereafter, the battery was discharged at 0.05 C to 2.5 V. Then, after CC-CV to 0.2V at 4.0V, discharge to 2.5V at 0.2C, discharge to 2.5V at 0.2C, and discharge to 2.5V at 0.2C Then, the non-aqueous electrolyte secondary battery was stabilized. Then, after performing CC-CV charge to 4.3V at 0.2C, it discharged to 2.5V at 0.2C and performed initial conditioning.

The cell after the initial conditioning was stored at 60 ° C. for 168 hours at a high temperature. After the battery was sufficiently cooled, it was immersed in an ethanol bath to measure the volume, and the amount of generated gas was determined from the change in volume before and after the storage test, and this was defined as the "preserved gas amount". 0.2C at 25 ° C
Discharge to 2.5 V to determine the capacity after high-temperature storage characteristics evaluation, and call this the “0.2 C capacity after storage”.
And
Table 5 below shows the amount of stored gas and the 0.2 C capacity after storage, normalized by the values of Comparative Example 4-1.

<Example 5-1 and Comparative example 5-1>
[Preparation of non-aqueous electrolyte]
Under a dry argon atmosphere, a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (DEC) (volume ratio by volume 3: 4: 3) was dried sufficiently on Li
PF ₆ was dissolved at 1.2 mol / L (as the concentration in the non-aqueous electrolyte), and then vinylene carbonate (VC), fluoroethylene carbonate and adiponitrile were each added in an amount of 2.5 mol / L.
, 1.0 and 1.0% by mass (this is referred to as reference electrolyte 5). Compounds were added to the entire reference electrolyte solution 5 at the ratios shown in Table 6 below to prepare an electrolyte solution. However, Comparative Example 5-1
Is the reference electrolyte 5 itself.

[Preparation of positive electrode]
97% by mass of lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, 1.5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) as a binder 1.
5% by mass was mixed in an N-methylpyrrolidone solvent with a disperser to form a slurry. This was uniformly applied on both sides of an aluminum foil having a thickness of 21 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
98 parts by mass of graphite powder as a negative electrode active material, 1 part by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and 1 part by mass of an aqueous dispersion of styrene-butadiene rubber as a thickener and a binder, respectively. 1 part by mass (concentration of styrene-butadiene rubber: 50% by mass) was added and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a copper foil having a thickness of 12 μm, dried, and then pressed to obtain a negative electrode.

[Manufacture of non-aqueous electrolyte battery (laminated type)]
The above positive electrode, negative electrode, and polyolefin separator were laminated in the order of negative electrode, separator, positive electrode, separator, and negative electrode. The battery element thus obtained was wrapped in an aluminum laminate film, and an electrolyte solution to be described later was injected and then vacuum-sealed to produce a sheet-like non-aqueous electrolyte secondary battery.

<Evaluation of non-aqueous electrolyte secondary battery>
[Continuous charging test] The nonaqueous electrolyte battery after the initial capacity evaluation was performed at 60 ° C.
A continuous charging test was performed by performing CC-CV charging (cut for 168 hours) to 4.38 V at 0.2 C. Thereafter, after the battery was sufficiently cooled, the battery was immersed in an ethanol bath to measure the volume, and the “continuously charged gas amount” was determined from the volume change before and after continuous charging.
Table 6 below shows the continuously charged gas amount normalized by the value of Comparative Example 5-1.

<Example 6-1 and Comparative example 6-1>
[Preparation of non-aqueous electrolyte]
In a dry argon atmosphere, a sufficiently dry LiPF ₆ (1.0 mol / L, as a concentration in a non-aqueous electrolyte) was added to a mixture of ethylene carbonate and diethyl carbonate (DEC) (volume-volume ratio of 3: 7). And (k) vinylene carbonate (VC) and (g)
) Monofluoroethylene carbonate was added in an amount of 2.0% by mass (this is referred to as reference electrolyte 5). Compounds were added to the entire reference electrolyte solution 6 at the ratios shown in Table 7 below to prepare an electrolyte solution. However, Comparative Example 6-1 is the reference electrolyte 6 itself.

[Preparation of positive electrode]
97% by mass of lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, 1.5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) as a binder 1.
5% by mass was mixed in an N-methylpyrrolidone solvent with a disperser to form a slurry. This was uniformly applied on both sides of an aluminum foil having a thickness of 21 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
98 parts by mass of graphite powder as a negative electrode active material, 1 part by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and 1 part by mass of an aqueous dispersion of styrene-butadiene rubber as a thickener and a binder, respectively. 1 part by mass (concentration of styrene-butadiene rubber: 50% by mass) was added and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a copper foil having a thickness of 12 μm, dried, and then pressed to obtain a negative electrode.

[Manufacture of non-aqueous electrolyte battery (laminated type)]
The above positive electrode, negative electrode, and polyolefin separator were laminated in the order of negative electrode, separator, positive electrode, separator, and negative electrode. The battery element thus obtained was wrapped in an aluminum laminate film, and an electrolyte solution to be described later was injected and then vacuum-sealed to produce a sheet-like non-aqueous electrolyte secondary battery.

<Evaluation of non-aqueous electrolyte secondary battery>
[Evaluation of discharge storage characteristics]
After the initial capacity evaluation, the non-aqueous electrolyte battery was subjected to 3.0 V at 0.2 C at 25 ° C.
CC-CV charging (0.05 C cut) was performed until this time. Thereafter, high-temperature storage was performed at 60 ° C. for 168 hours. The voltage before and after storage is measured, and the difference is referred to as “voltage change after discharge storage (mV).
". After the battery was sufficiently cooled, it was immersed in an ethanol bath to measure the volume, and the amount of generated gas was determined from the change in volume before and after the storage test, and this was defined as the “discharge storage gas amount”.

[Charge storage test]
After the cell after the initial capacity evaluation was again charged with CC-CV at 0.2 C to 4.35 V,
High-temperature storage was performed at 85 ° C. for 24 hours. After the battery was sufficiently cooled, it was immersed in an ethanol bath to measure the volume, and the amount of generated gas was determined from the change in volume before and after the storage test, and this was defined as the "charge storage gas amount".
Table 7 below shows the initial resistance, the change in voltage after discharge storage, the amount of discharge storage gas, and the amount of charge storage gas normalized by the values of Comparative Example 6-1.

<Examples 7-1 to 7-2, Comparative Examples 7-1 and 7-2>
[Preparation of non-aqueous electrolyte]
Under a dry argon atmosphere, a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (DEC) (volume ratio by volume 3: 4: 3) was dried sufficiently on Li
The PF ₆ 1.2 mol / L (non-as the concentration of the aqueous electrolyte solution) is dissolved, further, (referred to as reference electrolyte 7) with the addition of fluoroethylene carbonate 5.0% by weight. Compounds were added to the entire reference electrolyte solution 7 at the ratios shown in Table 8 below to prepare an electrolyte solution. However, Comparative Example 7-1 is the reference electrolyte 7 itself.

[Preparation of positive electrode]
97% by mass of lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, 1.5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) as a binder 1.
5% by mass was mixed in an N-methylpyrrolidone solvent with a disperser to form a slurry. This was uniformly applied on both sides of an aluminum foil having a thickness of 21 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
98 parts by mass of natural graphite powder as a negative electrode active material, 1 part by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of sodium carboxymethylcellulose 1 mass%) and 1 part by mass of a styrene-butadiene rubber as a thickener and a binder, respectively. 1 part by mass of John (concentration of styrene-butadiene rubber: 50% by mass) was added and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a copper foil having a thickness of 12 μm, dried, and then pressed to obtain a negative electrode.

[Manufacture of non-aqueous electrolyte battery (laminated type)]
The above positive electrode, negative electrode, and polyolefin separator were laminated in the order of negative electrode, separator, positive electrode, separator, and negative electrode. The battery element thus obtained was wrapped in an aluminum laminate film, and an electrolyte solution to be described later was injected and then vacuum-sealed to produce a sheet-like non-aqueous electrolyte secondary battery.

<Evaluation of non-aqueous electrolyte secondary battery>
[Initial capacity]
The non-aqueous electrolyte secondary battery of the laminate type cell was charged at a constant current of 0.05 C for 6 hours in a thermostat at 25 ° C., and then discharged to 3.0 V at 0.2 C. 4.1V at 0.2C
CC-CV charging was performed up to this point. Thereafter, aging was performed at 45 ° C. for 72 hours. Thereafter, the battery was discharged to 3.0 V at 0.2 C to stabilize the non-aqueous electrolyte secondary battery. Furthermore, after performing CC-CV charging to 0.25C to 4.35V, it discharged to 0.5V to 3.0V, and made the discharge capacity "initial capacity."

[Storage test]
After the cell after the initial capacity evaluation was again charged with CC-CV at 0.2 C to 4.35 V,
High-temperature storage was performed at 60 ° C. for 168 hours. After sufficiently cooling the battery, the battery was immersed in an ethanol bath to measure the volume, and the amount of generated gas was determined from the change in volume before and after the storage test, and this was defined as the “amount of stored gas”. Thereafter, the battery was discharged to 3.0 V at 0.2 C at 25 ° C.
After performing CC-CV charging up to 4.35 V at 2 C, discharging to 3.0 V at 0.5 C, and the discharge capacity was defined as “capacity after storage”.
In Table 8 below, the initial volume, the gas volume after storage, the volume after storage, normalized by the values of Comparative Example 7-1,
Is shown.

<Example 8-1, Comparative Example 8-1>
[Preparation of non-aqueous electrolyte]
Under a dry argon atmosphere, a mixture of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate (DEC) (volume ratio by volume 3: 4: 3) was dried sufficiently on Li
PF ₆ was dissolved at 1.2 mol / L (as the concentration in the non-aqueous electrolyte), and 5.0% by mass of fluoroethylene carbonate was added (this is referred to as reference electrolyte 8). Compounds were added to the entire reference electrolyte solution 8 at the ratios shown in Table 9 below to prepare an electrolyte solution. However, Comparative Example 8-1 is the reference electrolyte 8 itself.

[Preparation of positive electrode]
97% by mass of lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, 1.5% by mass of acetylene black as a conductive material, and polyvinylidene fluoride (PVdF) as a binder 1.
5% by mass was mixed in an N-methylpyrrolidone solvent with a disperser to form a slurry. This was uniformly applied on both sides of an aluminum foil having a thickness of 21 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
98 parts by mass of natural graphite powder as a negative electrode active material, 1 part by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of sodium carboxymethylcellulose 1 mass%) and 1 part by mass of a styrene-butadiene rubber as a thickener and a binder, respectively. 1 part by mass of John (concentration of styrene-butadiene rubber: 50% by mass) was added and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a copper foil having a thickness of 12 μm, dried, and then pressed to obtain a negative electrode.

[Manufacture of non-aqueous electrolyte battery (laminated type)]
The above positive electrode, negative electrode, and polyolefin separator were laminated in the order of negative electrode, separator, positive electrode, separator, and negative electrode. The battery element thus obtained was wrapped in an aluminum laminate film, and an electrolyte solution to be described later was injected and then vacuum-sealed to produce a sheet-like non-aqueous electrolyte secondary battery.

<Evaluation of non-aqueous electrolyte secondary battery>
[Initial rate characteristics]
The non-aqueous electrolyte secondary battery of the laminate type cell was charged at a constant current of 0.05 C for 6 hours in a thermostat at 25 ° C., and then discharged to 3.0 V at 0.2 C. 4.1V at 0.2C
CC-CV charging was performed up to this point. Thereafter, aging was performed at 45 ° C. for 72 hours. Thereafter, the battery was discharged to 3.0 V at 0.2 C to stabilize the non-aqueous electrolyte secondary battery. Further, after performing CC-CV charging up to 4.35 V at 0.2 C, 3.0 V at 0.2 C / 1.0 C.
And the capacity ratio (1.0 C capacity / 0.2 C capacity) was defined as “initial rate characteristic”.

[Rate characteristics after storage]
After the cell after the initial capacity evaluation was again charged with CC-CV at 0.2 C to 4.35 V,
High-temperature storage was performed at 60 ° C. for 168 hours. Then, at 25 ° C. and 0.2 C.
After discharging to 0 V and performing CC-CV charging again at 0.2 C to 4.35 V,
Discharge was performed at 1.0 C to 3.0 V, and the capacity ratio (1.0 C capacity / 0.2 C capacity) was defined as “rate characteristic after storage”.
Table 9 below shows the initial rate characteristics and the post-storage rate characteristics normalized by the values of Comparative Example 8-1.

<Examples 9-1 to 9-3, Comparative examples 9-1 to 9-3>
[Preparation of non-aqueous electrolyte]
In a dry argon atmosphere, 1 mol / L (as a concentration in a non-aqueous electrolyte) of sufficiently dried LiPF ₆ is dissolved in a mixture of ethylene carbonate and diethyl carbonate (DEC) (volume-volume ratio of 3: 7). Further, 2.0 mass% of each of vinylene carbonate (VC) and fluoroethylene carbonate was added (this is referred to as reference electrolyte 9). Compounds were added to the entire reference electrolyte solution 9 at the ratios shown in Table 10 below to prepare an electrolyte solution. However, Comparative Example 9-1 is the reference electrolyte 9 itself.

[Preparation of positive electrode]
Lithium-nickel-cobalt-manganese composite oxide (NMC) 85 as positive electrode active material
A mass%, acetylene black 10 mass% as a conductive material, and polyvinylidene fluoride (PVdF) 5 mass% as a binder were mixed in an N-methylpyrrolidone solvent with a disperser to form a slurry. This was uniformly applied on both sides of an aluminum foil having a thickness of 21 μm, dried, and then pressed to obtain a positive electrode.

[Preparation of negative electrode]
50 g of Si fine particles having an average particle diameter of 0.2 μm are converted into 2000 g of flaky graphite having an average particle diameter of 35 μm.
The mixture was dispersed in the apparatus, charged into a hybridization system (manufactured by Nara Machinery Co., Ltd.), and circulated or retained in the apparatus at a rotor rotation speed of 7000 rpm for 180 seconds to be processed to obtain a composite of Si and graphite particles. The obtained composite was mixed with coal tar pitch as an organic compound to be a carbonaceous material so that the coverage after firing was 7.5%, and kneaded and dispersed by a biaxial kneader. The resulting dispersion was introduced into a firing furnace and fired at 1000 ° C. for 3 hours in a nitrogen atmosphere. The obtained fired product was further pulverized by a hammer mill and then sieved (45 μm) to prepare a negative electrode active material. The content of the silicon element, the average particle diameter d50, the tap density, and the specific surface area measured by the above measurement method were 2.0% by mass, 20 μm, 1.0 g / cm ³ , and 7.2 m ² / g, respectively. .

97.5 parts by mass of the negative electrode active material, 1 part by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of 1% by mass of sodium carboxymethylcellulose) and 1 part by mass of a styrene-butadiene rubber as a thickener and a binder, respectively.
1.5 parts by mass of a styrene-butadiene rubber (concentration of 50% by mass) was added, and mixed with a disperser to form a slurry. This slurry was uniformly applied to one surface of a copper foil having a thickness of 10 μm, dried, and then pressed to obtain a negative electrode.

[Manufacture of non-aqueous electrolyte battery (laminated type)]
The above positive electrode, negative electrode, and polyolefin separator were laminated in the order of negative electrode, separator, and positive electrode. Wrap the battery element thus obtained in an aluminum laminate film,
After injecting an electrolytic solution described later, it was vacuum-sealed to produce a sheet-like nonaqueous electrolytic solution secondary battery.

<Evaluation of non-aqueous electrolyte secondary battery>
[High temperature storage test]
In a constant temperature bath at 25 ° C., the nonaqueous electrolyte secondary battery of the laminate type cell was charged at a constant current-constant voltage up to 4.0 V with a current corresponding to 0.05 C. Thereafter, the battery was discharged at 0.05 C to 2.5 V. Then, after CC-CV to 0.2V at 4.0V, discharge to 2.5V at 0.2C, discharge to 2.5V at 0.2C, and discharge to 2.5V at 0.2C Then, the non-aqueous electrolyte secondary battery was stabilized. Then, after performing CC-CV charge to 4.3V at 0.2C, it discharged to 2.5V at 0.2C and performed initial conditioning.

The cell after the initial conditioning was stored at 60 ° C. for 168 hours at a high temperature. After the battery was sufficiently cooled, it was immersed in an ethanol bath to measure the volume, and the amount of generated gas was determined from the change in volume before and after the storage test, and this was defined as the "preserved gas amount". 0.2C at 25 ° C
Discharge to 2.5 V to determine the capacity after high-temperature storage characteristics evaluation, and call this the “0.2 C capacity after storage”.
And

[High-temperature cycle test] The cells after the initial conditioning were placed in a 45 ° C constant temperature bath at a temperature of 0.5 ° C.
After performing CC-CV charging to 4.2 V with C, the process of discharging to 2.5 V at a constant current of 0.5 C was defined as one cycle, and 100 cycles were performed. The capacity at the 100th cycle was defined as “capacity after 100 cycles”.
In Table 10 below, the gas amount after storage, 0.2 C capacity after storage, normalized by the value of Comparative Example 9-1,
The capacity after 100 cycles is shown.

ADVANTAGE OF THE INVENTION According to the non-aqueous electrolyte solution of this invention, the capacity | capacitance deterioration at the time of high temperature preservation of a non-aqueous electrolyte battery can be improved. Therefore, it can be suitably used in all fields such as electronic devices using a non-aqueous electrolyte secondary battery.
The use of the non-aqueous electrolyte and the non-aqueous electrolyte secondary battery of the present invention is not particularly limited, and can be used for various known applications. Specific examples of its uses include laptop computers, e-book players, mobile phones, mobile faxes, mobile copiers, mobile printers, mobile audio players, small video cameras, LCD TVs, handy cleaners, transceivers, electronic organizers, calculators, memories Cards, portable tape recorders, radios, backup power supplies, automobiles, motorcycles, motorized bicycles, bicycles, lighting fixtures, toys, game machines, watches, electric tools, strobes, cameras, and the like can be given.

Claims (10)

A non-aqueous electrolyte for a non-aqueous electrolyte battery including a positive electrode and a negative electrode capable of occluding and releasing metal ions, wherein the non-aqueous electrolyte is represented by the following general formula (A) together with an electrolyte and a non-aqueous solvent. Selected from the group consisting of compounds having a structure, and (1) a nitrile compound, an isocyanate compound, a difluorophosphate, a fluorosulfonate, a lithium bis (fluorosulfonyl) imide, and a compound represented by the following general formula (B). Characterized in that (2) a cyclic carbonate compound having a fluorine atom is contained in an amount of 0.01 to 50.0% by weight based on the total amount of the nonaqueous electrolytic solution. Electrolyte.

(In the formula (A), R ^{1 to} R ³ are an alkyl group having a trimethylsilyl group as a substituent.)

(In the formula (B), R ¹ , R ^2, and R ³ each independently represent an alkyl group, an alkenyl group, or an alkynyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom. 0
Represents an integer of up to 6. ) The amount of the compound having the structure represented by the general formula (A) is 0.01% by weight or more and 10.0% by weight or less based on the total amount of the non-aqueous electrolyte. The non-aqueous electrolytic solution according to 1. The nitrile compound, isocyanate compound, difluorophosphate, fluorosulfonate, lithium bis (fluorosulfonyl) imide and the compound represented by the following general formula (B) are used in an amount of 0.01 to 0.01% based on the total amount of the non-aqueous electrolyte. The non-aqueous electrolyte according to claim 1, wherein the content is not less than 10% by weight and not more than 10.0% by weight. The cyclic carbonate compound having a fluorine atom is at least one compound selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, and 4,5-difluoroethylene carbonate. 9. The non-aqueous electrolyte according to claim 1. The non-aqueous electrolyte solution is at least one selected from the group consisting of cyclic carbonates having carbon-carbon unsaturated bonds, acid anhydrides, vinyl sulfonic acid esters, aromatic compounds having 12 or less carbon atoms, and chain carboxylic acid esters. The non-aqueous electrolyte solution according to claim 1, wherein the non-aqueous electrolyte solution contains a compound of the formula (1). 5. A non-aqueous electrolyte secondary battery comprising a positive electrode capable of occluding and releasing lithium ions, a negative electrode capable of occluding and releasing lithium ions, and a non-aqueous electrolyte, wherein the non-aqueous electrolyte comprises: A non-aqueous electrolyte battery according to any one of claims 1 to 4. The nonaqueous electrolyte battery according to claim 6, wherein the negative electrode active material of the negative electrode capable of storing and releasing lithium ions has carbon as a constituent element. The non-aqueous electrolyte battery according to claim 6, wherein the negative electrode active material of the negative electrode capable of inserting and extracting lithium ions has silicon (Si) or tin (Sn) as a constituent element. 9. The negative electrode active material of the negative electrode capable of occluding and releasing lithium ions is a mixture or a composite of particles having silicon (Si) or tin (Sn) as a constituent element and graphite particles. 3. The non-aqueous electrolyte battery according to claim 1. The content of the particles containing silicon (Si) or tin (Sn) as a constituent element is 0.1 to 25% by mass based on the total of the particles containing silicon (Si) or tin (Sn) and the graphite particles. The non-aqueous electrolyte battery according to claim 9, wherein: