JP5350880B2 - Non-aqueous electrolyte and non-aqueous electrolyte secondary battery using the electrolyte - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte for a secondary battery, which can maintain a small internal resistance and a high electric capacity for a long time of service; and to provide a nonaqueous electrolyte secondary battery using the nonaqueous electrolyte. <P>SOLUTION: The nonaqueous electrolyte for the secondary battery made by dissolving an electrolytic salt into an organic solvent contains a dicarbonate compound represented by the general formula (1), wherein R<SP>1</SP>denotes a 3-8C secondary linear alkyl group, a 4-8C branching alkyl group, or a 1-8C alkyl chloride group, R<SP>2</SP>denotes a 1-8C alkyl group or a 1-8C alkyl chloride group, R<SP>3</SP>and R<SP>4</SP>each independently denote a hydrogen atom or a 1-8C alkyl group, and n denotes a number that is 1 or 2. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a non-aqueous electrolyte solution containing a dicarbonate compound having a specific structure and a non-aqueous electrolyte secondary battery using the electrolyte solution.

  With the spread of portable electronic devices such as portable personal computers, handy video cameras, and information terminals in recent years, non-aqueous electrolyte secondary batteries having high voltage and high energy density have been widely used as power sources. Also, from the viewpoint of environmental problems, battery cars and hybrid cars using electric power as a part of power have been put into practical use.

  In non-aqueous electrolyte secondary batteries, a decrease in electric capacity and an increase in internal resistance occur due to high temperature storage or repeated charge / discharge. In order to improve the stability and electrical characteristics of nonaqueous electrolyte batteries, various additives for electrolyte solutions have been proposed. Examples of such additives include 1,3-propane sultone (for example, see Patent Document 1), vinyl ethylene carbonate (for example, see Patent Document 2), vinylene carbonate (for example, see Patent Document 3), 1, 3-Propane sultone, butane sultone (for example, refer to Patent Document 4), vinylene carbonate (for example, refer to Patent Document 5), vinyl ethylene carbonate (for example, refer to Patent Document 6), and the like have been proposed. Carbonate is widely used because of its great effect. These additives form a stable film called SEI (Solid Electrolyte Interface) on the surface of the negative electrode, and this film covers the surface of the negative electrode, thereby suppressing the reductive decomposition of the electrolyte. It is considered.

  However, the film formed by these conventional additives on the negative electrode is not sufficiently durable, and the secondary battery cannot be used stably for a long period of time. In order to make up for this weak point, when an additive is added excessively, the thickness of the formed film increases, the resistance increase rate increases, and conversely, the battery performance decreases. Therefore, the addition of these additives to the electrolytic solution has been insufficient to improve the balance of both battery output and capacity.

  As an additive having high durability of the coating film formed on the negative electrode, a cyclic carbonate compound substituted with a chlorine group and fluorine (for example, see Patent Document 7) is known. In addition, since the reductive decomposability is not sufficient, it is necessary to increase the amount of addition to the electrolytic solution, which is not only economically disadvantageous but also has a problem that the performance of the battery is lowered.

  On the other hand, dimethyl dicarbonate of 2-butyne-1,4-diol or 2,4-hexadiyne-1,6-diol (for example, see Patent Documents 8 to 12) is also used as an additive for the electrolyte for secondary batteries. Proposed. The electrolyte solution to which 2-butyne-1,4-diol or 2,4-hexadiyne-1,6-diol dimethyl dicarbonate is added can maintain the performance of the battery for a long time when the temperature change is small. There was a problem that the performance of the battery suddenly deteriorated when used under conditions with large changes. This is because the polymer density and reductive decomposability of 2-butyne-1,4-diol and 2,4-hexadiyne-1,6-diol on the negative electrode of dimethyl dicarbonate are high, so that the film density is increased and SEI is increased. This is considered to be due to peeling from the negative electrode surface when the coating becomes brittle and the temperature change is large.

JP 63-102173 A JP-A-4-87156 Japanese Patent Laid-Open No. 5-74486 Japanese Patent Laid-Open No. 10-50342 JP-A-8-045545 JP 2001-6729 A JP-A-62-290072 JP 2000-195545 A JP 2002-1000039 A Table 2005/008829 Table 2005/117197 Table 2006/077773

  Accordingly, an object of the present invention is to provide a non-aqueous electrolyte for a secondary battery capable of maintaining a small internal resistance and a high electric capacity during long-term use, and a non-aqueous electrolyte secondary battery using the non-aqueous electrolyte. Is to provide.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by adding a dicarbonate compound having a specific structure, and have completed the present invention.

（式中、Ｒ¹ 及びＲ ² は炭素数３〜８の２級直鎖アルキル基、炭素数４〜８の分岐アルキル基又は炭素数１〜８の塩化アルキル基を表わし、Ｒ ³ 及びＲ⁴は各々独立して水素原子又は炭素数１〜８のアルキル基を表わし、ｎは１又は２の数を表す。）
で表されるジカーボネート化合物を含有することを特徴とする、二次電池用非水電解液を提供するものである。
That is, the present invention relates to a non-aqueous electrolyte for a secondary battery in which an electrolyte salt is dissolved in an organic solvent.

(In the formula, R ¹ and R ² represent a secondary linear alkyl group having 3 to 8 carbon atoms, a branched alkyl group having 4 to 8 carbon atoms, or an alkyl chloride group having 1 to 8 carbon atoms ; R ³ and R ⁴ Each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and n represents a number of 1 or 2.)
The non-aqueous electrolyte for secondary batteries characterized by containing the dicarbonate compound represented by these is provided.

  Moreover, this invention provides the non-aqueous electrolyte secondary battery which has the said non-aqueous electrolyte.

According to the non-aqueous electrolyte for a secondary battery of the present invention, it is possible to maintain a small internal resistance and a high electric capacity in a long-term use, and there is little deterioration in the performance of the battery even under a large temperature change condition. Can be provided.

FIG. 1 is a longitudinal sectional view schematically showing an example of the structure of a coin-type battery of the nonaqueous electrolyte secondary battery of the present invention. FIG. 2 is a schematic diagram showing a basic configuration of a cylindrical battery of the nonaqueous electrolyte secondary battery of the present invention. FIG. 3 is a perspective view showing the internal structure of the cylindrical battery of the nonaqueous electrolyte secondary battery of the present invention as a cross section.

Hereinafter, the nonaqueous electrolytic solution of the present invention will be described in detail based on preferred embodiments.
The nonaqueous electrolytic solution of the present invention is characterized in that a dicarbonate compound having a specific structure, specifically, a dicarbonate compound represented by the general formula (1) is contained in the electrolytic solution. Yes. The dicarbonate compound represented by the general formula (1) has appropriate polymerizability on the surface of the negative electrode in the non-aqueous electrolyte, and forms SEI having a coating density on the surface of the negative electrode. A non-aqueous electrolyte secondary battery using a non-aqueous electrolyte contained therein can maintain a small internal resistance and high electric capacity for a long period of time, and there is little deterioration in battery performance even under conditions of large temperature changes. Conceivable.

In the general formula (1), R ¹ represents a secondary linear alkyl group having 3 to 8 carbon atoms, a branched alkyl group having 4 to 8 carbon atoms, or an alkyl chloride group having 1 to 8 carbon atoms. In the present invention, the linear alkyl group refers to an alkyl group in which carbon atoms are linearly bonded, and the secondary linear alkyl group refers to an alkyl group in which the carbon bonded to other groups is carbon other than the terminal. say.

  Examples of the secondary linear alkyl group having 3 to 8 carbon atoms include isopropyl, 2-butyl, 2-pentyl, 3-pentyl, 2-hexyl, 3-hexyl, 2-heptyl, 3-heptyl, 4- Examples include heptyl, 2-octyl, 3-octyl and 4-octyl.

  Examples of the branched alkyl group having 4 to 8 carbon atoms include isobutyl, t-butyl, 2-methylbutyl, isopentyl, neopentyl, t-pentyl, 2-methylpentyl, 1,1-dimethylbutyl, 1-methylhexyl, Examples thereof include 2-ethylpentyl, 1,1-dimethylpentyl, 2-ethylhexyl, 1,1-dimethylhexyl and the like.

  As said C1-C8 alkyl chloride group, the alkyl chloride group whose number of a chlorine atom is 1 is preferable from stability of a compound. Examples of the alkyl chloride group include chloromethyl, 2-chloroethyl, 2-chloropropyl, 3-chloropropyl, 2-chloro-2-propyl, 2-chlorobutyl, 3-chlorobutyl, 4-chlorobutyl, and 3-chloro. 2-butyl, 1-chloro-2-butyl, 2-chloro-1,1-dimethylethyl, 3-chloro-2-methylpropyl, 5-chloropentyl, 3-chloro-2-methylpropyl, 3-chloro -2,2-dimethyl, 6-chlorohexyl and the like.

As R ¹ , since there are few adverse effects on the movement of lithium ions and the charging characteristics are good, isopropyl, isobutyl, 2-butyl, t-butyl, isopentyl, 2-pentyl, t-pentyl, neopentylchloromethyl, 2-chloroethyl, 3-chloropropyl, 4-chlorobutyl, 5-chloropentyl and 6-chlorohexyl are preferred, t-butyl, isopentyl, neopentyl, 3-chloropropyl and 4-chlorobutyl are more preferred, isopropyl, 3-chloro Propyl is most preferred.

R ² represents an alkyl group having 1 to 8 carbon atoms or an alkyl chloride group having 1 to 8 carbon atoms. As the alkyl group having 1 to 8 carbon atoms, in addition to the secondary linear alkyl group having 3 to 8 carbon atoms and the branched alkyl group having 4 to 8 carbon atoms exemplified in the description of R ¹ , A primary linear alkyl group is mentioned. Examples of the primary linear alkyl group having 1 to 8 carbon atoms include methyl, ethyl, propyl, butyl, hexyl, heptyl and octyl.

R ² is preferably a secondary straight-chain alkyl group having 3 to 8 carbon atoms or a branched alkyl group having 4 to 8 carbon atoms because stable battery performance can be obtained even when the temperature change is large. Among them, since there is little adverse effect on the movement of lithium ions and the charging characteristics are good, isopropyl, isobutyl, 2-butyl, t-butyl, isopentyl, 2-pentyl, t-pentyl, neopentylchloromethyl, 2- Chloroethyl, 3-chloropropyl, 4-chlorobutyl, 5-chloropentyl and 6-chlorohexyl are preferable, and isopropyl, t-butyl, isopentyl, neopentyl, 3-chloropropyl and 4-chlorobutyl are more preferable, isopropyl, 3-chloro Propyl is most preferred.

R ¹ and R ² may be the same group or different groups, but are preferably the same group because of easy production.

R ³ and R ⁴ each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms include a primary linear alkyl group having 1 to 8 carbon atoms, a secondary linear alkyl group having 3 to 8 carbon atoms, and 4 carbon atoms exemplified in the description of R ¹ or R ^2. -8 branched alkyl groups. R ³ and R ⁴ are preferably a hydrogen atom, methyl, ethyl, or propyl, more preferably a hydrogen atom or methyl, and most preferably a hydrogen atom, since there is little adverse effect on the movement of lithium ions and good charging characteristics. .

  In the general formula (1), n represents 1 or 2. In the general formula (1), when only n is different and all other than n are the same, the target product is obtained in good yield, which is advantageous in terms of production. preferable.

  Among the dicarbonate compounds represented by the general formula (1), examples of the compound in which n is 1 include 2-butyne-1,4-diol diisopropyl dicarbonate and 2-butyne-1,4-diol bis. (2-butyl) dicarbonate, 2-butyne-1,4-dioldiisobutyldicarbonate, 2-butyne-1,4-dioldi (t-butyl) dicarbonate, 2-butyne-1,4-diolbis (2- Pentyl) dicarbonate, 2-butyne-1,4-diol diisopentyl dicarbonate, 2-butyne-1,4-diol di (t-pentyl) dicarbonate, 2-butyne-1,4-diol dineopentyl di Carbonate, 2-butyne-1,4-dioldi (chloromethyl) dicarbonate, 2-butyne-1,4-diolbis ( -Chloroethyl) dicarbonate, 2-butyne-1,4-diol bis (3-chloropropyl) dicarbonate, 2-butyne-1,4-diol bis (4-chlorobutyl) dicarbonate, 2-butyne-1,4-diol bis (5-chloropentyl) dicarbonate, 3-hexyne-2,5-dioldiisopropyldicarbonate, 3-hexyne-2,5-diolbis (2-butyl) dicarbonate, 3-hexyne-2,5-dioldiisobutyldi Carbonate, 3-hexyne-2,5-dioldi (t-butyl) dicarbonate, 3-hexyne-2,5-diolbis (2-pentyl) dicarbonate, 3-hexyne-2,5-dioldiisopentyldicarbonate 3-hexyne-2,5-diol di (t-pentyl) dicar 3-hexyne-2,5-diol dineopentyl dicarbonate, 3-hexyne-2,5-diol di (chloromethyl) dicarbonate, 3-hexyne-2,5-diol bis (2-chloroethyl) dicarbonate, 3-hexyne-2,5-diol bis (3-chloropropyl) dicarbonate, 3-hexyne-2,5-diol bis (4-chlorobutyl) dicarbonate, 3-hexyne-2,5-diol bis (5-chloropentyl) Dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol diisopropyl dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol bis (2-butyl) dicarbonate, 2,5-dimethyl 3- Hexin-2,5-diol diisobutyl dicarbonate, 2,5-dimethyl 3- Hexin-2,5-diol di (t-butyl) dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol bis (2-pentyl) dicarbonate, 2,5-dimethyl 3-hexyne-2,5- Diol diisopentyl dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol di (t-pentyl) dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol dineopentyl dicarbonate, 2 , 5-dimethyl 3-hexyne-2,5-diol di (chloromethyl) dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol bis (2-chloroethyl) dicarbonate, 2,5-dimethyl 3-hexyne -2,5-diol bis (3-chloropropyl) dicarbonate, 2,5-dimethyl 3-hexyne-2,5-di Rubisu (4-chlorobutyl) dicarbonate, 2,5-dimethyl-3-hexyne-2,5-Jiorubisu (5-chloropentyl) dicarbonate and the like.

Among these compounds, 2-butyne-1,4-diol diisopropyl dicarbonate, 2-butyne-1,4-diol diisobutyl dicarbonate, 2-butyne-1,4-diol diisopentyl dicarbonate, 2-butyne -1,4-diol dineopentyl dicarbonate, 2-butyne-1,4-diol bis (3-chloropropyl) dicarbonate, 2-butyne-1,4-diol bis (4-chlorobutyl) dicarbonate, 3-hexyne -2,5-diol diisopropyl dicarbonate, 3-hexyne-2,5-diol diisobutyl dicarbonate, 3-hexyne-2,5-diol diisopentyl dicarbonate, 3-hexyne-2,5-diol dineopentyl Dicarbonate, 3-hexyne-2,5-diol bis ( -Chloropropyl) dicarbonate, 3-hexyne-2,5-diol bis (4-chlorobutyl) dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol diisopropyl dicarbonate, 2,5-dimethyl 3-hexyne -2,5-diol diisobutyl dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol diisopentyl dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol dineopentyl dicarbonate, 2,5-dimethyl-3-hexyne-2,5-diol bis (3-chloropropyl) dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol bis (4-chlorobutyl) dicarbonate are more preferable,
2-butyne-1,4-diol diisopropyl dicarbonate, 2-butyne-1,4-diol diisobutyl dicarbonate, 2-butyne-1,4-diol bis (3-chloropropyl) dicarbonate, 3-hexyne-2, 5-diol diisopropyl dicarbonate, 3-hexyne-2,5-diol diisobutyl dicarbonate, 3-hexyne-2,5-diol bis (3-chloropropyl) dicarbonate, 2,5-dimethyl 3-hexyne-2,5 -Diol diisopropyl dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol diisobutyl dicarbonate, 2,5-dimethyl 3-hexyne-2,5-diol bis (3-chloropropyl) dicarbonate are more preferred,
2-butyne-1,4-diol diisopropyl dicarbonate, 2-butyne-1,4-diol diisobutyl dicarbonate, and 2-butyne-1,4-diol bis (3-chloropropyl) dicarbonate are most preferred.

  Among the dicarbonate compounds represented by the general formula (1), examples of the compound in which n is 2 are 2,4-hexadiyne-1,6-dioldiisopropyldicarbonate, 2,4-hexadiyne-1 , 6-diol bis (2-butyl) dicarbonate, 2,4-hexadiyne-1,6-diol diisobutyl dicarbonate, 2,4-hexadiyne-1,6-diol di (t-butyl) dicarbonate, 2,4- Hexadiyne-1,6-diol bis (2-pentyl) dicarbonate, 2,4-hexadiyne-1,6-diol diisopentyl dicarbonate, 2,4-hexadiyne-1,6-diol di (t-pentyl) dicarbonate 2,4-hexadiyne-1,6-diol dineopentyl dicarbonate, 2,4-hexadi 1,6-dioldi (chloromethyl) dicarbonate, 2,4-hexadiyne-1,6-diolbis (2-chloroethyl) dicarbonate, 2,4-hexadiyne-1,6-diolbis (3-chloropropyl) Dicarbonate, 2,4-hexadiyne-1,6-diolbis (4-chlorobutyl) dicarbonate, 2,4-hexadiyne-1,6-diolbis (5-chloropentyl) dicarbonate, 3,5-octadiyne-2, 7-diol diisopropyl dicarbonate, 3,5-octadiyne-2,7-diol bis (2-butyl) dicarbonate, 3,5-octadiyne-2,7-diol diisobutyl dicarbonate, 3,5-octadiyne-2,7 Diol di (t-butyl) dicarbonate, 3,5-octadii -2,7-diol bis (2-pentyl) dicarbonate, 3,5-octadiyne-2,7-diol diisopentyl dicarbonate, 3,5-octadiyne-2,7-diol di (t-pentyl) dicarbonate, 3,5-octadiyne-2,7-diol dineopentyl dicarbonate, 3,5-octadiyne-2,7-diol di (chloromethyl) dicarbonate, 3,5-octadiyne-2,7-diol bis (2-chloroethyl) ) Dicarbonate, 3,5-octadiyne-2,7-diol bis (3-chloropropyl) dicarbonate, 3,5-octadiyne-2,7-diol bis (4-chlorobutyl) dicarbonate, 3,5-octadiyne-2 , 7-diol bis (5-chloropentyl) dicarbonate, 2,7-dimethyl 3,5-octadiyne-2,7-diol diisopropyl dicarbonate, 2,7-dimethyl-3,5-octadiyne-2,7-diol bis (2-butyl) dicarbonate, 2,7-dimethyl-3,5 -Octadiyne-2,7-diol diisobutyl dicarbonate, 2,7-dimethyl-3,5-octadiyne-2,7-diol di (t-butyl) dicarbonate, 2,7-dimethyl-3,5-octadiyne-2 , 7-diol bis (2-pentyl) dicarbonate, 2,7-dimethyl-3,5-octadiyne-2,7-diol diisopentyl dicarbonate, 2,7-dimethyl-3,5-octadiyne-2,7 -Diol di (t-pentyl) dicarbonate, 2,7-dimethyl-3,5-octadiyne-2,7-diol dineopen Dicarbonate, 2,7-dimethyl-3,5-octadiyne-2,7-dioldi (chloromethyl) dicarbonate, 2,7-dimethyl-3,5-octadiyne-2,7-diolbis (2-chloroethyl) dicarbonate Carbonate, 2,7-dimethyl-3,5-octadiyne-2,7-diol bis (3-chloropropyl) dicarbonate, 2,7-dimethyl-3,5-octadiyne-2,7-diol bis (4-chlorobutyl) Examples include dicarbonate and 2,7-dimethyl-3,5-octadiyne-2,7-diol bis (5-chloropentyl) dicarbonate.

Among these compounds, 2,4-hexadiyne-1,6-diol diisopropyl dicarbonate, 2,4-hexadiyne-1,6-diol diisobutyl dicarbonate, 2,4-hexadiyne-1,6-diol diisopentyl di Carbonate, 2,4-hexadiyne-1,6-diol dineopentyl dicarbonate, 2,4-hexadiyne-1,6-diol bis (3-chloropropyl) dicarbonate, 2,4-hexadiyne-1,6-diol bis (4-Chlorobutyl) dicarbonate, 3,5-octadiyne-2,7-diol diisopropyl dicarbonate, 3,5-octadiyne-2,7-diol diisobutyl dicarbonate, 3,5-octadiyne-2,7-diol di Isopentyl dicarbonate, 3,5-octa In-2,7-diol dineopentyl dicarbonate, 3,5-octadiyne-2,7-diol bis (3-chloropropyl) dicarbonate, 3,5-octadiyne-2,7-diol bis (4-chlorobutyl) dicarbonate Carbonate, 2,7-dimethyl-3,5-octadiyne-2,7-diol diisopropyl dicarbonate, 2,7-dimethyl-3,5-octadiyne-2,7-diol diisobutyl dicarbonate, 2,7-dimethyl- 3,5-octadiyne-2,7-diol diisopentyl dicarbonate, 2,7-dimethyl-3,5-octadiyne-2,7-diol dineopentyl dicarbonate, 2,7-dimethyl-3,5- Octadiyne-2,7-diol bis (3-chloropropyl) dicarbonate, 2,7-dimethyl 3,5-octadiyne-2,7 Jiorubisu (4-chlorobutyl) dicarbonate is more preferred,
2,4-hexadiyne-1,6-diol diisopropyl dicarbonate 2,4-hexadiyne-1,6-diol diisobutyl dicarbonate, 2,4-hexadiyne-1,6-diol bis (3-chloropropyl) dicarbonate, 3, , 5-octadiyne-2,7-diol diisopropyl dicarbonate, 3,5-octadiyne-2,7-diol diisobutyl dicarbonate, 3,5-octadiyne-2,7-diol bis (3-chloropropyl) dicarbonate, 2, , 7-dimethyl-3,5-octadiyne-2,7-diol diisopropyl dicarbonate, 2,7-dimethyl-3,5-octadiyne-2,7-diol diisobutyl dicarbonate, 2,7-dimethyl-3,5 -Octadiyne-2,7-diol bis (3-chloro Propyl) dicarbonate is more preferred,
2,4-hexadiyne-1,6-diol diisobutyl dicarbonate and 2,4-hexadiyne-1,6-diol bis (3-chloropropyl) dicarbonate are most preferred.

  In the nonaqueous electrolytic solution of the present invention, if the content of the dicarbonate compound represented by the general formula (1) is too small, a sufficient effect cannot be exhibited, and if it is too large, it corresponds to the blending amount. In addition to not being able to obtain an increasing effect, the properties of the non-aqueous electrolyte may be adversely affected. Therefore, the content of the dicarbonate compound represented by the general formula (1) is 0 in the non-aqueous electrolyte. 0.01 to 5 mass% is preferable, 0.03 to 4 mass% is more preferable, and 0.05 to 3 mass% is most preferable.

  The dicarbonate compound represented by the general formula (1) may be used alone or in combination of two or more.

（式中、Ｒ⁵は炭素数２〜８のアルケニル基又は炭素数２〜８のアルキニル基を表わし、Ｒ⁶〜Ｒ⁸は各々独立して、エーテル基若しくはハロゲン基を有してもよい炭素数１〜８のアルキル基又はアルケニル基を表す。）
で表される不飽和カルボン酸シリルエステル化合物を含有することが好ましい。 Since the non-aqueous electrolyte of the present invention increases the stability of battery performance, the following general formula (2)

(In the formula, R ⁵ represents an alkenyl group having 2 to 8 carbon atoms or an alkynyl group having 2 to 8 carbon atoms, and R ^{6 to} R ⁸ each independently represents carbon which may have an ether group or a halogen group. Represents an alkyl group or an alkenyl group of formula 1-8.)
It is preferable to contain the unsaturated carboxylic acid silyl ester compound represented by these.

In the general formula (2), R ⁵ represents an alkenyl group having 2 to 8 carbon atoms or an alkynyl group having 2 to 8 carbon atoms.

  Examples of the alkenyl group having 2 to 8 carbon atoms include vinyl, 1-propenyl, allyl, isopropenyl, 1-butenyl, 1-methyl-1-propenyl, 2-methyl-1-propenyl, 1-pentenyl, 1 -Hexenyl, 1-heptenyl, 1-octenyl are mentioned. Examples of the alkynyl group having 2 to 8 carbon atoms include ethynyl, 1-propynyl, 1-butynyl, 1-pentynyl, 1-hexynyl, 1-heptynyl, 1 -Octynyl.

R ⁹ is preferably vinyl, 1-propenyl, isopropenyl, 1-butenyl, ethynyl, or 1-propynyl because it has little adverse effect on the movement of lithium ions and good charge characteristics, and vinyl, ethynyl, 1- Propinyl is more preferred.

In the said General formula (2), R < ⁶ > -R < ⁸ > represents the C1-C8 alkyl group or alkenyl group which may have an ether group or a halogen group each independently. The alkyl group having 1 to 8 carbon atoms having a halogen group, in addition to the chlorinated alkyl groups exemplified for R ¹ of the general formula (1), trifluoromethyl, 2-fluoroethyl, 2,2,2-trifluoroethyl Ethyl, 1,1,2,2-tetrafluoroethyl, pentafluoroethyl, 3-fluoropropyl, 3,3,3-trifluoropropyl, 2,2,3,3-tetrafluoropropyl, heptafluoropropyl, etc. Can be mentioned. Examples of the alkyl group having 1 to 8 carbon atoms having an ether group include 3-methoxypropyl, 3-ethoxypropyl, 3-propoxypropyl, 4-methoxybutyl, 4-ethoxybutyl, 4-propoxybutyl, 4-butoxybutyl, Examples include 3-methoxy-2-methylpropyl, 3-ethoxy-2-methylpropyl, 3-propoxy-2-methylpropyl, and the like. Examples of the alkenyl group include vinyl, allyl, butenyl, 1-trifluoromethylvinyl and the like.

As R ^{10 to} R ¹¹ , methyl and ethyl are preferable, and methyl is more preferable because it has little adverse effect on lithium ion migration and good charge characteristics.

  Preferable specific examples of the unsaturated carboxylic acid silyl ester compound represented by the general formula (2) include trimethylsilyl acrylate, trimethylsilyl methacrylate, trimethylsilyl crotonic acid, trimethylsilyl 2-butenoate, and 2-methyl-2-butenoic acid. Trimethylsilyl, trimethylsilyl 2-pentenoate, trimethylsilyl 2-hexenoate, trimethylsilyl 2-heptenoate, trimethylsilyl 2-octenoate, trimethylsilyl 2-nonenate, trimethylsilyl propinate, trimethylsilyl 2-butynoate, trimethylsilyl 2-pentenoate, 2- Examples include trimethylsilyl hexinate, trimethylsilyl 2-heptate, trimethylsilyl 2-octate, trimethylsilyl 2-noninate, and among these compounds, acrylic acid Trimethylsilyl, trimethylsilyl methacrylate, 2-pentenoic acid trimethylsilyl, propionic acid trimethylsilyl, 2-butyne-trimethylsilyl is preferred, trimethylsilyl acrylate, propionic acid trimethylsilyl, 2-butyne trimethylsilyl more preferred.

  In the nonaqueous electrolytic solution of the present invention, if the content of the unsaturated carboxylic acid silyl ester compound represented by the general formula (2) is too small, a sufficient effect cannot be exhibited, and if the content is too large, The content of the unsaturated carboxylic acid silyl ester compound represented by the general formula (2) is not only the effect of increasing the amount corresponding to the blending amount but also adversely affecting the characteristics of the non-aqueous electrolyte. In the non-aqueous electrolyte, 0.001 to 5 mass% is preferable, 0.003 to 4 mass% is more preferable, and 0.005 to 3 mass% is most preferable.

  The unsaturated carboxylic acid silyl ester compound represented by the general formula (2) may be used alone or in combination of two or more.

  Since the non-aqueous electrolyte of the present invention further increases the cycle characteristics of charging, the cyclic carbonate compound, the chain carbonate compound, the unsaturated diester compound, the halogenated cyclic carbonate compound, the cyclic sulfite ester or the cyclic group having an unsaturated group. It is preferable to contain a sulfate ester.

Examples of the cyclic carbonate compound having an unsaturated group include vinylene carbonate, vinyl ethylene carbonate, propylidene carbonate, ethylene ethylidene carbonate, ethylene isopropylidene carbonate, and among these compounds, vinylene carbonate or vinyl ethylene carbonate is preferable. .
Examples of the chain carbonate compound include dipropargyl carbonate, propargyl methyl carbonate, ethyl propargyl carbonate, bis (1-methylpropargyl) carbonate, bis (1-dimethylpropargyl) carbonate, and the like.
Examples of the unsaturated diester compounds include dimethyl maleate, diethyl maleate, dipropyl maleate, dibutyl maleate, dipentyl maleate, dihexyl maleate, diheptyl maleate, dioctyl maleate, dimethyl fumarate, diethyl fumarate, and fumaric acid. Dipropyl, dibutyl fumarate, dipentyl fumarate, dihexyl fumarate, diheptyl fumarate, dioctyl fumarate, dimethyl acetylenedicarboxylate, diethyl acetylenedicarboxylate, dipropyl acetylenedicarboxylate, dibutyl acetylenedicarboxylate, dipentyl acetylenedicarboxylate, acetylenedicarboxylic acid Dihexyl, diheptyl acetylenedicarboxylate, dioctyl acetylenedicarboxylate, etc.
Examples of the halogenated cyclic carbonate compound include chloroethylene carbonate, dichloroethylene carbonate, fluoroethylene carbonate, and difluoroethylene carbonate.
Examples of the sulfite ester include ethylene sulfite.
Examples of the cyclic sulfate include propane sultone and butane sultone.

  Among these additives, vinylene carbonate, vinyl ethylene carbonate, dipropargyl carbonate, dimethyl acetylenedicarboxylate, diethyl acetylenedicarboxylate, chloroethylene carbonate, dichloroethylene carbonate, fluoroethylene carbonate, ethylene sulfite, propane sultone, butane sultone are preferable, More preferred are vinylene carbonate, dipropargyl carbonate, dimethyl acetylenedicarboxylate, chloroethylene carbonate, fluoroethylene carbonate, ethylene sulfite, propane sultone, and vinylene carbonate, dipropargyl carbonate, chloroethylene carbonate, fluoroethylene carbonate, ethylene sulfite, propane. Sulton is most preferred Arbitrariness. These additives may be used alone or in combination of two or more.

  In the nonaqueous electrolytic solution of the present invention, if the content of these additives is too small, a sufficient effect cannot be exhibited, and if it is too large, an increase effect corresponding to the blending amount cannot be obtained. On the contrary, since the properties of the non-aqueous electrolyte may be adversely affected, the content of these additives is preferably 0.005 to 10% by mass and 0.02 to 5% by mass in the non-aqueous electrolyte. More preferably, 0.05-3 mass% is the most preferable.

  As an organic solvent used for the non-aqueous electrolyte of the present invention, those usually used for non-aqueous electrolytes can be used alone or in combination of two or more. Specific examples include a cyclic carbonate compound, a cyclic ester compound, a sulfone or sulfoxide compound, an amide compound, a chain carbonate compound, a chain ether compound, a cyclic ether compound, and a saturated chain ester compound.

  Since the above cyclic carbonate compound, cyclic ester compound, sulfone or sulfoxide compound and amide compound have a high relative dielectric constant, they serve to increase the dielectric constant of the electrolytic solution. Among these organic solvents, a cyclic carbonate compound is particularly preferable.

Specifically, examples of the cyclic carbonate compound include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, and isobutylene carbonate.
Examples of the cyclic ester compound include γ-butyrolactone, γ-valerolactone, and the like.
Examples of the sulfone or sulfoxide compound include sulfolane, sulfolene, tetramethylsulfolane, diphenyl sulfone, dimethyl sulfone, dimethyl sulfoxide, and the like. Among these compounds, sulfolane and tetramethylsulfolane are preferable.
Examples of the amide compound include N-methylpyrrolidone, dimethylformamide, dimethylacetamide and the like.

  The above-mentioned chain carbonate compound, chain ether compound, cyclic ether compound and chain ester compound can reduce the viscosity of the non-aqueous electrolyte, increase the mobility of electrolyte ions, etc. The battery characteristics such as can be made excellent. Moreover, since it is low-viscosity, the performance of the non-aqueous electrolyte at low temperatures can be increased. Among these organic solvents, a chain carbonate compound is preferable.

Specifically, as the chain carbonate compound, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), ethyl-butyl carbonate, methyl-t-butyl carbonate, di-isopropyl carbonate, t -Butyl-propyl carbonate and the like,
Examples of the chain or cyclic ether compound include dimethoxyethane (DME), ethoxymethoxyethane, diethoxyethane, tetrahydrofuran, dioxolane, dioxane, 1,2-bis (methoxycarbonyloxy) ethane, 1,2-bis (ethoxycarbonyl). Oxy) ethane, 1,2-bis (ethoxycarbonyloxy) propane, ethylene glycol bis (trifluoroethyl) ether, propylene glycol bis (trifluoroethyl) ether, ethylene glycol bis (trifluoromethyl) ether, diethylene glycol bis (tri Fluoroethyl) ether and the like. Among these compounds, dioxolanes are preferable.

  As the organic solvent of the nonaqueous electrolytic solution of the present invention, one or more solvents (organic solvent A) selected from the group consisting of the above cyclic carbonate compounds, cyclic ester compounds, sulfone or sulfoxide compounds and amide compounds, A mixed solvent with at least one solvent (organic solvent B) selected from the group consisting of a chain carbonate compound, a chain ether compound, a cyclic ether compound and a chain ester compound is not only excellent in cycle characteristics, but also an electrolytic solution. It is preferable that a nonaqueous electrolytic solution having a good balance between the viscosity of the obtained battery and the electric capacity / output of the battery obtained can be provided, and a mixed solvent of the cyclic carbonate compound and the chain carbonate compound is more preferable. When a mixed solvent of the organic solvent A and the organic solvent B is used as the organic solvent, the mixing ratio (volume basis) of the organic solvent A and the organic solvent B is preferably 1:10 to 10: 1. : 3 is more preferable.

  The nonaqueous electrolytic solution of the present invention can further improve battery characteristics at a low temperature by further containing a saturated chain ester compound as an organic solvent. In particular, the organic solvent has a chain structure with a cyclic carbonate compound. In the case of a mixed solvent with a carbonate compound, battery characteristics at low temperatures can be greatly improved.

  As the saturated chain ester compound, monoester compounds and diester compounds having a total number of carbon atoms in the molecule of 2 to 8 are preferable. Specific compounds include methyl formate, ethyl formate, methyl acetate, ethyl acetate, Propyl acetate, isobutyl acetate, butyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethyl acetate, ethyl trimethyl acetate, methyl malonate, ethyl malonate, methyl succinate, ethyl succinate, 3- Examples include methyl methoxypropionate, ethyl 3-methoxypropionate, ethylene glycol diacetyl, propylene glycol diacetyl, and the like. Methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, isobutyl acetate, butyl acetate, methyl propionate, propio Ethyl are preferred.

  In the non-aqueous electrolyte of the present invention, if the content of the saturated chain ester compound is too small, a sufficient effect cannot be exhibited, and if it is too large, an increase effect corresponding to the blending amount cannot be obtained. On the other hand, the content of the saturated chain ester compound is preferably 0.5 to 30% by mass in the non-aqueous electrolyte because it may adversely affect the characteristics of the non-aqueous electrolyte. More preferably, it is 10 mass%.

  In addition, acetonitrile, propionitrile, nitromethane, and derivatives thereof can also be used as the organic solvent.

  In addition, halogen-based, phosphorus-based, and other flame retardants can be appropriately added to the nonaqueous electrolytic solution of the present invention in order to impart flame retardancy. For example, phosphoric acid esters such as trimethyl phosphate and triethyl phosphate are listed as phosphorus flame retardants. If the amount of flame retardant added is too small, sufficient flame retarding effect cannot be achieved.If it is too large, not only an increase effect corresponding to the blending amount can be obtained, but on the other hand, the characteristics of the non-aqueous electrolyte Since it may have a bad influence, it is preferable that it is 5-100 mass% with respect to the organic solvent which comprises the non-aqueous electrolyte of this invention, and it is still more preferable that it is 10-50 mass%.

As the electrolyte salt used in the nonaqueous electrolytic solution of the present invention, a conventionally known electrolyte salt is used. For example, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiN (CF ₃ SO _{2) 2, LiC (CF 3} SO 2) 3, LiB (CF 3 SO 3) 4, LiB (C 2 O 4) 2, LiSbF 6, LiSiF 5, LiAlF 4, LiSCN, LiClO 4, LiCl, LiF, LiBr LiI, LiAlF ₄ , LiAlCl ₄ , NaClO ₄ , NaBF ₄ , NaI, and derivatives thereof, among these electrolyte salts, LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN derivative of (CF ₃ SO _{2) 2} and LiC (CF ₃ SO _{2) 3} and _{LiCF 3 SO 3, LiN (CF} 3 SO 2) _It is preferable to use one or more selected from the group consisting of a derivative of ₂ and a derivative of LiC (CF ₃ SO ₂ ) ₃ because of excellent electrical characteristics.

  The electrolyte salt can be dissolved in the organic solvent so that the concentration in the nonaqueous electrolytic solution of the present invention is 0.1 to 3.0 mol / L, particularly 0.5 to 2.0 mol / L. preferable. If the concentration of the electrolyte salt is less than 0.1 mol / L, a sufficient current density may not be obtained, and if it is more than 3.0 mol / L, the stability of the non-aqueous electrolyte may be impaired.

  The non-aqueous electrolyte solution of the present invention described above can be used as a non-aqueous electrolyte solution for either a primary battery or a secondary battery. However, the non-aqueous electrolyte solution constituting a secondary battery, particularly a lithium ion secondary battery. Can be suitably used.

Next, the nonaqueous electrolyte secondary battery of the present invention will be described.
The non-aqueous electrolyte secondary battery of the present invention is configured in the same manner as a conventionally known non-aqueous electrolyte secondary battery except that the above-described non-aqueous electrolyte of the present invention is used as the non-aqueous electrolyte.

  The electrode material constituting the non-aqueous electrolyte secondary battery of the present invention includes a positive electrode and a negative electrode. As the positive electrode, a positive electrode active material, a binder, and a conductive material are slurried with an organic solvent or water. It is applied to a current collector and dried to form a sheet.

As the positive electrode active material, if a lithium ion secondary battery is taken as an example, a known positive electrode active material capable of inserting and extracting lithium as an electrode reactant can be used. Specific examples of the positive electrode active material capable of occluding and releasing lithium include metal oxides such as TiO ₂ , V ₂ O ₅ and MnO ₂ , metals such as TiS ₂ , TiS ₃ , MoS ₃ and FeS _2. Examples thereof include metal compounds such as sulfides, metal halides such as FeF ₃ , metal intercalation compounds, and metal phosphate compounds. These positive electrode active materials may be a material obtained by adding or replacing a transition metal such as lithium, magnesium, aluminum, cobalt, titanium, niobium, or chromium. Among these, composite oxides containing lithium and a transition metal element are preferable, and those containing at least one of nickel, cobalt, manganese, titanium, and iron are particularly preferable as the transition metal element.

Such a composite oxide containing lithium and a transition metal element typically has the following general formula (3):
Li _x M ¹ O ₂ (3)
(In the formula, M ¹ represents one or more kinds of transition metal elements, and the value of x represents a number that normally satisfies 0.05 ≦ x ≦ 1.10.
The compound represented by the general formula (3) generally has a layered structure.

Examples of the composite oxide containing lithium and a transition metal element include a lithium cobalt composite oxide (Li _x CoO ₂ ), a lithium nickel composite oxide (Li _x NiO ₂ ), or a lithium nickel cobalt composite oxide (Li _x Ni _1z Co _z O ₂ (z <1)), lithium nickel cobalt manganese complex oxide (Li _x Ni _1-vw Co _v Mn _w O ₂ (v + w <1)), etc. Composite oxides containing different additive elements, lithium manganese composite oxides having a layered structure or spinel structure (LiMn ₂ O ₄ ), composite oxides containing different additive elements based on lithium manganese composite oxide structures, etc. Can be mentioned.

Examples of the phosphorous oxide containing lithium and a transition metal element include a lithium iron phosphoric acid compound (LiFePO ₄ ) having an olivine structure and a lithium iron manganese phosphate compound (LiFe _1-u Mn _u PO ₄ ( Examples thereof include compounds containing different additive elements based on lithium iron phosphate structure, such as u <1)).

  The surface of the positive electrode active material may be coated with a conductive material to be described later if necessary.

  Examples of the binder include polyvinylidene fluoride, polytetrafluoroethylene, EPDM, SBR, NBR, fluororubber, and polyacrylic acid. The usage-amount of the said binder is about 0.1-20 mass% normally with respect to a positive electrode active material, Preferably it is 0.5-10 mass%.

  Examples of the conductive material include graphite fine particles, carbon black such as acetylene black and ketjen black, amorphous carbon fine particles such as needle coke, and carbon nanofibers. The usage-amount of the said electrically conductive material is about 5-60 mass% normally with respect to a positive electrode active material, Preferably it is 10-50 mass%.

  As the solvent for forming a slurry, an organic solvent or water that dissolves the binder is used. Examples of the organic solvent include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, NN-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran and the like. The usage-amount of the said solvent is about 25-400 mass% normally with respect to a positive electrode active material, Preferably it is 50-200 mass%.

  Usually, aluminum, stainless steel, nickel-plated steel, or the like is used for the positive electrode current collector.

  As the negative electrode, a material obtained by applying a slurry obtained by slurrying a negative electrode active material and a binder with an organic solvent or water to a current collector and drying it into a sheet is usually used.

  Examples of the negative electrode active material include lithium, lithium alloys, inorganic compounds such as tin / silicon compounds, titanium oxides, carbonaceous materials, and conductive polymers. In particular, a carbonaceous material that can occlude and release highly safe lithium ions is preferable. Such carbonaceous materials are not particularly limited, but include natural graphite, artificial, fullerene, graphite fiber chops, carbon nanotubes, graphite whiskers, highly oriented pyrolytic graphite, quiche graphite and other crystalline carbon, and petroleum coke, Coal-based coke, petroleum-based pitch carbide, coal-based pitch carbide, phenolic resin / crystalline cellulose resin carbide, etc., and partially carbonized carbon materials, furnace black, acetylene black, pitch-based carbon fiber, PAN-based Carbon fiber etc. are mentioned.

  Examples of the binder and the solvent to be slurried include the same as those for the positive electrode. The usage-amount of the said binder is about 0.1-20 mass% normally with respect to a negative electrode active material, Preferably it is about 0.5-10 mass%. Moreover, the usage-amount of the said solvent is about 50-200 mass% normally with respect to a negative electrode active material, Preferably it is 60-150 mass%.

  Usually, copper, nickel, stainless steel, nickel-plated steel, aluminum or the like is used for the current collector of the negative electrode.

  In the non-aqueous electrolyte secondary battery of the present invention, a separator is used between the positive electrode and the negative electrode. As the separator, a commonly used polymer microporous film can be used without any particular limitation. Examples of the film include polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, polyethylene oxide and polypropylene oxide. Films composed of ethers, various celluloses such as carboxymethylcellulose and hydroxypropylcellulose, polymer compounds mainly composed of poly (meth) acrylic acid and various esters thereof, derivatives thereof, copolymers and mixtures thereof. Etc. These films may be used alone, or may be used as a multilayer film by superimposing these films. Furthermore, various additives may be used for these films, and the kind and content thereof are not particularly limited. Among these films, a film made of polyethylene, polypropylene, polyvinylidene fluoride, or polysulfone is preferably used for the nonaqueous electrolyte secondary battery of the present invention.

  These films are microporous so that the electrolyte can penetrate and ions can easily pass therethrough. The microporosity method includes a phase separation method in which a polymer compound and a solvent solution are formed into a film while microphase separation is performed, and the solvent is extracted and removed to make it porous. The film is extruded and then heat treated, the crystals are arranged in one direction, and a “stretching method” or the like is performed by forming a gap between the crystals by stretching, and is appropriately selected depending on the film used.

  In the non-aqueous electrolyte secondary battery of the present invention, the electrode material, the non-aqueous electrolyte, and the separator include a phenol-based antioxidant, a phosphorus-based antioxidant, and a thioether-based antioxidant for the purpose of improving safety. A hindered amine compound or the like may be added.

  Examples of the phenolic antioxidant include 1,6-hexamethylenebis [(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionic acid amide], 4,4′-thiobis (6-t -Butyl-m-cresol), 4,4'-butylidenebis (6-t-butyl-m-cresol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxy Benzyl) isocyanurate, 1,3,5-tris (3,5-di-t-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, tetrakis [3- (3,5-di-t -Butyl- -Hydroxyphenyl) propionate methyl] methane, thiodiethylene glycol bis [(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 1,6-hexamethylene bis [(3,5-di-t- Butyl-4-hydroxyphenyl) propionate], bis [3,3-bis (4-hydroxy-3-tert-butylphenyl) butyric acid] glycol ester, bis [2-tert-butyl-4-methyl-6- (2-Hydroxy-3-t-butyl-5-methylbenzyl) phenyl] terephthalate, 1,3,5-tris [(3,5-di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate 3,9-bis [1,1-dimethyl-2-{(3-tert-butyl-4-hydroxy-5-methylphenyl ) Propionyloxy} ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, triethylene glycol bis [(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate] and the like. When added to the electrode material, it is preferable to use 0.01 to 10 parts by mass, particularly 0.05 to 5 parts by mass with respect to 100 parts by mass of the electrode material.

Examples of the phosphorus antioxidant include trisnonylphenyl phosphite and tris [2-t-butyl-4- (3-t-butyl-4-hydroxy-5-methylphenylthio) -5-methylphenyl]. Phosphite, tridecyl phosphite, octyl diphenyl phosphite, di (decyl) monophenyl phosphite, di (tridecyl) pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di -T-butylphenyl) pentaerythritol diphosphite, bis (2,6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4,6-tri-t-butylphenyl) Pentaerythritol diphosphite, bis (2,4-dicumylphenyl) Pentaerythritol diphosphite, tetra (tridecyl) isopropylidene diphenol diphosphite, tetra (tridecyl) -4,4′-n-butylidenebis (2-t-butyl-5-methylphenol) diphosphite, hexa (tridecyl)- 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane triphosphite, tetrakis (2,4-di-t-butylphenyl) biphenylene diphosphonite, 9,10-dihydro -9-oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis (4,6-t-butylphenyl) -2-ethylhexyl phosphite, 2,2'-methylenebis (4,6 -T-butylphenyl) -octadecyl phosphite, 2,2'-ethylidenebis ( , 6-di-t-butylphenyl) fluorophosphite, tris (2-[(2,4,8,10-tetrakis-t-butyldibenzo [d, f] [1,3,2] dioxaphosphine) Pin-6-yl) oxy] ethyl) amine, 2-ethyl-2-butylpropylene glycol and 2,4,6-tri-t-butylphenol phosphite.

  Examples of the thioether-based antioxidant include dialkylthiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, and pentaerythritol tetra (β-alkylmercaptopropionate esters). Is mentioned.

  Examples of the hindered amine compound include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-4-piperidyl stearate, 2,2,6,6. -Tetramethyl-4-piperidylbenzoate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2, 3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, bis (2,2,6,6) -Tetramethyl-4-piperidyl) -di (tridecyl) -1,2,3,4-butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-pi Lysyl) .di (tridecyl) -1,2,3,4-butanetetracarboxylate, bis (1,2,2,4,4-pentamethyl-4-piperidyl) -2-butyl-2- (3,5 -Di-t-butyl-4-hydroxybenzyl) malonate, 1- (2-hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol / diethyl succinate polycondensate, 1,6 -Bis (2,2,6,6-tetramethyl-4-piperidylamino) hexane / 2,4-dichloro-6-morpholino-s-triazine polycondensate, 1,6-bis (2,2,6, 6-tetramethyl-4-piperidylamino) hexane / 2,4-dichloro-6-t-octylamino-s-triazine polycondensate, 1,5,8,12-tetrakis [2,4-bis (N- Butyl-N- (2,2,6 6-tetramethyl-4-piperidyl) amino) -s-triazin-6-yl] -1,5,8,12-tetraazadodecane, 1,5,8,12-tetrakis [2,4-bis (N -Butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino) -s-triazin-6-yl] -1,5,8-12-tetraazadodecane, 1,6, 11-tris [2,4-bis (N-butyl-N- (2,2,6,6-tetramethyl-4-piperidyl) amino) -s-triazin-6-yl] aminoundecane, 1,6, Hindered amine compounds such as 11-tris [2,4-bis (N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino) -s-triazin-6-yl] aminoundecane Is mentioned.

  The shape of the non-aqueous electrolyte secondary battery of the present invention having the above configuration is not particularly limited, and can be various shapes such as a coin shape, a cylindrical shape, and a square shape. FIG. 1 shows an example of a coin-type battery of the nonaqueous electrolyte secondary battery of the present invention, and FIGS. 2 and 3 show examples of a cylindrical battery, respectively.

  In the coin-type non-aqueous electrolyte secondary battery 10 shown in FIG. 1, 1 is a positive electrode capable of releasing lithium ions, 1a is a positive electrode current collector, and 2 is a carbonaceous material capable of inserting and extracting lithium ions released from the positive electrode. The negative electrode current collector, 2a is a negative electrode current collector, 3 is a non-aqueous electrolyte of the present invention, 4 is a stainless steel positive electrode case, 5 is a stainless steel negative electrode case, 6 is a polypropylene gasket, and 7 is a polyethylene separator. It is.

  Further, in the cylindrical non-aqueous electrolyte secondary battery 10 ′ shown in FIGS. 2 and 3, 11 is a negative electrode, 12 is a negative electrode assembly, 13 is a positive electrode, 14 is a positive electrode current collector, and 15 is a non-electrode of the present invention. Water electrolyte, 16 separator, 17 positive electrode terminal, 18 negative electrode terminal, 19 negative electrode plate, 20 negative electrode lead, 21 positive electrode plate, 22 positive electrode lead, 23 case, 24 insulating plate, 25 gasket , 26 are safety valves, and 27 is a PTC element.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, these do not restrict | limit the scope of the present invention. In the examples, “parts” and “%” are based on mass unless otherwise specified.

[Synthesis Example 1] Synthesis of Compound A1 A 300 ml three-necked flask equipped with a reflux was charged with 17.2 g of 2-butyne-1,4-diol, 51.2 g of pyridine and 50 ml of ethyl acetate, and isopropyl chloroformate under a nitrogen atmosphere. The solution was added dropwise from a 61.2 g dropping funnel while cooling with ice. After the dropping, the reaction was further completed at room temperature for 2 hours. After the reaction, the reaction solution was washed thoroughly with water and purified by column chromatography to obtain 32.5 g (yield 63%) of compound A1 (2-butyne-1,4-dioldiisopropyldicarbonate). Compound A1 is a dicarbonate compound in which R ¹ and R ² are isopropyl, R ³ and R ⁴ are hydrogen atoms, and n is 1 in the above general formula (1).

[Synthesis Example 2] Synthesis of Compound A2 Except that 3-chloropropyl chloroformate was used in place of isopropyl chloroformate, the same operation as in Synthesis Example 1 was carried out to give compound A2 (2-butyne-1,4-diolbis ( 3-chloropropyl) dicarbonate). Compound A2 is a dicarbonate compound in which R ¹ and R ² are 3-chloropropyl, R ³ and R ⁴ are hydrogen atoms, and n is 1 in the general formula (1).

Synthesis Example 3 Synthesis of Compound A3 A 300 ml three-necked flask equipped with a reflux was charged with 36.3 g of propargyl alcohol (propynol), 51.2 g of pyridine and 50 ml of ethyl acetate, and 61.2 g of isopropyl chloroformate was added under a nitrogen atmosphere. The solution was added dropwise from the dropping funnel while cooling with ice. After the dropping, the reaction was further completed at room temperature for 2 hours. After the reaction, the reaction solution was washed thoroughly with water and distilled to obtain 66.4 g (yield 67%) of isopropylpropargyl carbonate.

A 1 L three-necked flask was charged with 66.4 g of the obtained isopropylpropargyl carbonate, 500 ml of acetone, 1.7 g of copper (I) chloride and 2.0 g of tetramethylethylenediamine (TMEDA), and the air was fed with an air pump for 12 hours at room temperature. Stir to complete the reaction. After the reaction, acetone is distilled off from the reaction solution with an evaporator, diluted with diethyl ether, the organic layer is thoroughly washed with a 3.6% hydrochloric acid aqueous solution and ion-exchanged water, dried over anhydrous sodium sulfate, and then the evaporator. Diethyl ether was distilled off to obtain a yellow oily substance. This oily substance was purified by column chromatography to obtain 58.7 g (yield 90%) of compound A3 (2,4-hexadiyne-1,6-dioldiisopropyldicarbonate). Compound A3 is a dicarbonate compound in which R ¹ and R ² are isopropyl, R ³ and R ⁴ are hydrogen atoms, and n is 2 in the above general formula (1).

[Synthesis Example 4] Synthesis of Compound A4 Except that 3-chloropropyl chloroformate was used in place of isopropyl chloroformate, the same procedure as in Synthesis Example 3 was performed, and compound A4 (2,4-hexadiyne-1,6- Diol bis (3-chloropropyl) dicarbonate) was obtained. Compound A4 is a dicarbonate compound in which R ¹ and R ² are 3-chloropropyl, R ³ and R ⁴ are hydrogen atoms, and n is 2 in the above general formula (1).

[Synthesis Example 5] Synthesis of Compound A5 Compound A5 (2,4-hexadiyne-1,6-dioldineo) was prepared in the same manner as in Synthesis Example 3 except that neopentyl chloroformate was used instead of isopropyl chloroformate. Pentyl dicarbonate) was obtained. Compound A5 is a dicarbonate compound in which R ¹ and R ² are neopentyl, R ³ and R ⁴ are hydrogen atoms, and n is 2 in the above general formula (1).

Synthesis Example 6 Synthesis of Compound A6 Synthesis Example 3 was used except that 2-butynol (1-methylpropinol) was used instead of propargyl alcohol and 3-chloropropyl chloroformate was used instead of isopropyl chloroformate. The same operation was performed to obtain Compound A6 (3,5-octadiyne-2,7-diol bis (3-chloropropyl) dicarbonate). Compound A6 is a compound in which R ¹ and R ² are 3-chloropropyl, R ³ is methyl, R ⁴ is a hydrogen atom, and n is 2 in the general formula (1).

[Synthesis Example 7] Synthesis of Compound A7 Except that t-butyl chloroformate was used in place of isopropyl chloroformate, the same operation as in Synthesis Example 3 was carried out to obtain Compound A7 (2,4-hexadiyne-1,6-diol di-). (T-butyl) dicarbonate) was obtained. Compound A7 is a compound in which R ¹ and R ² are t-butyl, R ³ and R ⁴ are hydrogen atoms, and n is 2 in the general formula (1).

[Examples 1 to 17 and Comparative Examples 1 to 8]
In the following Examples and Comparative Examples, non-aqueous electrolyte secondary batteries (lithium secondary batteries) were produced according to the following <Production Procedure> and evaluated.

<Production procedure>
[Production of positive electrode]
85 parts by mass of LiCoO ₂ as a positive electrode active material, 10 parts by mass of acetylene black as a conductive material, and 5 parts by mass of polyvinylidene fluoride (PVDF) as a binder were mixed to obtain a positive electrode material. This positive electrode material was dispersed in N-methyl-2-pyrrolidone (NMP) to form a slurry. This slurry was applied to both surfaces of an aluminum positive electrode current collector, dried, and press-molded to obtain a positive electrode plate. Then, this positive electrode plate was cut into a predetermined size to produce a disc-shaped positive electrode.

(Production of negative electrode)
97.0 parts by mass of artificial graphite as a negative electrode active material, 2.0 parts by mass of SBR and 1.0 part by mass of CMC as a binder were mixed to obtain a negative electrode material. This negative electrode material was dispersed in water to form a slurry. This slurry was applied to both sides of a copper negative electrode current collector, dried and press-molded to obtain a negative electrode plate. Then, this negative electrode plate was cut into a predetermined size to produce a disc-shaped negative electrode.

(Preparation of non-aqueous electrolyte)
LiPF ₆ was dissolved at a concentration of 1 mol / L in a mixed organic solvent composed of 30% by volume of ethylene carbonate, 40% by volume of ethyl methyl carbonate, 25% by volume of dimethyl carbonate and 5% by volume of butyl acetate. In this solution, test compounds (A1 to A7, B1 to B2, C1 to C2 and D1) were blended so as to have concentrations shown in Table 1 below, and the nonaqueous electrolysis of Examples 1 to 17 and Comparative Examples 1 to 8 A liquid was prepared. The numbers in parentheses in Table 1 represent the concentration (mass%) in the non-aqueous electrolyte.

In Table 1 above, test compounds other than compounds A1 to A7 are as follows.
<Comparative compound of compounds A1 to A7>
Compound B1: 2-butyne-1,4-diol dimethyl dicarbonate Compound B2: 2,4-hexadiyne-1,6-diol dimethyl dicarbonate <Compound of general formula (2)>
Compound C1: Trimethylsilyl acrylate Compound C2: Trimethylsilyl propinate <Cyclic carbonate compound having an unsaturated group>
Compound D1: Vinylene carbonate

[Assembling the battery]
The obtained disk-shaped positive electrode and disk-shaped negative electrode were held in a case with a polyethylene microporous film having a thickness of 25 μm interposed therebetween. Thereafter, the nonaqueous electrolytes of Examples 1 to 17 and Comparative Examples 1 to 8 were injected into the case, and the case was sealed and sealed to produce a coin-type lithium secondary battery having a diameter of 20 mm and a thickness of 3.2 mm. did.

  Using the lithium secondary batteries containing the non-aqueous electrolytes of Examples 1 to 17 and Comparative Examples 1 to 8 produced according to the above <Production Procedure>, the following test methods were used to perform initial characteristic tests, cycle characteristic tests, and 60 A storage test at 0 ° C. was performed. These test results are shown in Tables 2 and 3 below. In the initial characteristic test, the discharge capacity ratio (%) and the internal resistance ratio (%) were obtained. In the cycle characteristic test, the discharge capacity retention rate (%) and the internal resistance increase rate (%) were determined. In the 60 ° C. storage test, the discharge capacity retention rate (%) and the discharge capacity recovery rate (%) were determined.

<Initial characteristic test method>
1. Measurement method of discharge capacity ratio The prepared lithium secondary battery is placed in a constant temperature bath at 20 ° C., and is charged with constant current and constant voltage up to 4.2 V at a charging current of 0.3 mA / cm ² (current value corresponding to 0.2 C). Then, the operation of performing a constant current discharge to 3.0 V at a discharge current of 0.3 mA / cm ² (current value corresponding to 0.2 C) was performed for 5 cycles. Thereafter, as the sixth cycle, 4.2 V until a constant current and constant voltage charging at a charging current 0.3 mA / cm ^2, and a constant current discharge to 3.0V at a discharge current 0.3 mA / cm ^2. The discharge capacity measured after the end of these six cycles was taken as the initial discharge capacity. From this initial discharge capacity, the discharge capacity ratio (%) was determined according to the following formula.
Discharge capacity ratio (%) = [(initial discharge capacity) / (initial discharge capacity in Example 1)] × 100

2. Measurement method of internal resistance ratio The lithium secondary battery after the end of the sixth cycle is first charged at a constant current and constant voltage up to 3.75 V with a charging current of 1.5 mA / cm ² (current value equivalent to 1 C), and the AC impedance Using a measuring device (trade name: mobile potentiostat CompactStat, manufactured by IVIUM TECHNOLOGIES), scanning was performed from a frequency of 100 kHz to 0.02 Hz, and a Cole-Cole plot showing the imaginary part on the vertical axis and the real part on the horizontal axis was created. . Subsequently, in this Cole-Cole plot, the arc portion was fitted with a circle, and the larger one of the two points intersecting the real portion of this circle was used as the initial internal resistance. From this initial internal resistance, the internal resistance ratio (%) of the battery was determined according to the following formula.
Internal resistance ratio (%) = [(initial internal resistance) / (initial internal resistance in Example 1)] × 100

<Cycle characteristic test method>
1. Method for measuring discharge capacity retention rate The lithium secondary battery after the initial characteristic test was placed in a constant temperature bath at 60 ° C., and a charging current of 1.5 mA / cm ² (current value equivalent to 1 C, 1 C represents the battery capacity in 1 hour. The discharge capacity was measured after 150 cycles of a constant current charge to 4.2 V at a discharge current value) and a constant current discharge to 3.0 V at a discharge current of 1.5 mA / cm ² were repeated 150 times. From the 150th discharge capacity measured at this time and the initial discharge capacity, the discharge capacity retention rate (%) was determined according to the following formula.
Discharge capacity maintenance rate (%) = [(150th discharge capacity) / (initial discharge capacity)] × 100

2. Measuring method of internal resistance increase rate After the cycle characteristic test, the ambient temperature was set to 20 ° C., and the internal resistance at this time was measured in the same manner as the measuring method of the internal resistance ratio. From this internal resistance and the initial internal resistance, the rate of increase in internal resistance (%) was determined according to the following formula.
Internal resistance increase rate (%) = “(internal resistance after cycle−initial internal resistance) / (initial internal resistance)] × 100

<60 ° C storage test method>
1. Measuring method of discharge capacity maintenance rate The lithium ion secondary battery after the initial characteristic test is 4.2 V at a charging current of 0.3 mA / cm ² (current value corresponding to 0.2 C) as it is in a constant temperature bath at 20 ° C. After charging at constant current and constant voltage, it was transferred to a constant temperature bath at 60 ° C. and left for 14 days. Thereafter, the ambient temperature was returned to 20 ° C., and a constant current was discharged to 3.0 V at a discharge current of 0.3 mA / cm ² , and then the discharge capacity was measured. From the discharge capacity and the initial discharge capacity measured at this time, the discharge capacity retention rate (%) was determined according to the following formula.
Discharge capacity retention rate (%) = [(discharge capacity after storage at 60 ° C.) / (Initial discharge capacity)] × 100

2. Method for Measuring Discharge Capacity Recovery Rate Regarding the lithium secondary battery whose discharge capacity was measured, a charge current of 1.5 mA / cm ² (current value corresponding to 1 C, 1 C is a current value at which the battery capacity is discharged in 1 hour) is 4 The battery is charged at a constant current up to ² V and discharged at a discharge current of 1.5 mA / cm ² to 3.0 V. From the discharge capacity and the initial discharge capacity at this time, the discharge capacity recovery rate (%) is calculated according to the following formula. Asked.
Discharge capacity recovery rate (%) = [(discharge capacity after charging at 20 ° C. after storage at 60 ° C.) / (Initial discharge capacity)] × 100

  As is apparent from the results of Tables 2 and 3, the non-aqueous electrolyte secondary battery using the non-aqueous electrolyte of the present invention is excellent in terms of internal resistance and discharge capacity. It was confirmed that excellent battery characteristics could be maintained even after thermal cycling at 0 ° C.

Industrial applicability

  The non-aqueous electrolyte for secondary batteries of the present invention can provide a non-aqueous electrolyte secondary battery that can maintain a small internal resistance and a high discharge capacity even when used for a long period of time and when temperature changes are large. Such non-aqueous electrolyte secondary batteries include video cameras, digital cameras, portable music players, sound recorders, portable DVD players, portable game machines, notebook computers, electronic dictionaries, electronic notebooks, electronic books, mobile phones, mobile TVs, It can be used for various applications such as electric assist bicycles, battery cars, and hybrid cars. Among them, it can be suitably used for applications such as battery cars and hybrid cars that may be used at high temperatures.

DESCRIPTION OF SYMBOLS 1 Positive electrode 1a Positive electrode collector 2 Negative electrode 2a Negative electrode collector 3 Electrolyte 4 Positive electrode case 5 Negative electrode case 6 Gasket 7 Separator 10 Coin type nonaqueous electrolyte secondary battery 10 'Cylindrical type nonaqueous electrolyte secondary battery 11 Negative electrode 12 Negative electrode assembly 13 Positive electrode 14 Positive electrode assembly 15 Electrolyte 16 Separator 17 Positive electrode terminal 18 Negative electrode terminal 19 Negative electrode plate 20 Negative electrode lead 21 Positive electrode 22 Positive electrode lead 23 Case 24 Insulating plate 25 Gasket 26 Safety valve 27 PTC element

Claims (7)

In a non-aqueous electrolyte for a secondary battery in which an electrolyte salt is dissolved in an organic solvent, the following general formula (1)

(In the formula, R ¹ and R ² represent a secondary linear alkyl group having 3 to 8 carbon atoms, a branched alkyl group having 4 to 8 carbon atoms, or an alkyl chloride group having 1 to 8 carbon atoms ; R ³ and R ⁴ Each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and n represents a number of 1 or 2.)
A nonaqueous electrolytic solution for a secondary battery, comprising a dicarbonate compound represented by the formula:   The nonaqueous electrolytic solution for a secondary battery according to claim 1, wherein the content of the dicarbonate compound represented by the general formula (1) is 0.01 to 5% by mass. Furthermore, the following general formula (2)

(In the formula, R ⁵ represents an alkenyl group having 2 to 8 carbon atoms or an alkynyl group having 2 to 8 carbon atoms,
R ^{6 to} R ⁸ each independently represents an alkyl group or alkenyl group having 1 to 8 carbon atoms which may have an ether group or a halogen group. )
The non-aqueous electrolyte for secondary batteries of Claim 1 or 2 which contains 0.001-5 mass% of unsaturated carboxylic acid silyl ester compounds represented by these.   Furthermore, the cyclic carbonate compound which has an unsaturated group, a chain carbonate compound, an unsaturated diester compound, a halogenated cyclic carbonate compound, cyclic sulfite ester or cyclic sulfate ester is contained 0.005-10 mass%, Claims 1-3 The non-aqueous electrolyte for secondary batteries of any one of these.   The organic solvent is one or more solvents selected from the group consisting of cyclic carbonate compounds, cyclic ester compounds, sulfone or sulfoxide compounds and amide compounds, and chain carbonate compounds, chain ether compounds, cyclic ether compounds and chain esters. The nonaqueous electrolytic solution according to any one of claims 1 to 4, which is a mixed solvent with at least one solvent selected from the group consisting of compounds.   Furthermore, the non-aqueous electrolyte for secondary batteries of any one of Claims 1-5 containing 0.5-30 mass% of saturated chain ester compounds.   A nonaqueous electrolyte secondary battery comprising the nonaqueous electrolyte solution according to claim 1.

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