JP6915798B2 - Non-aqueous power storage element - Google Patents

Description

The present invention relates to a non-aqueous power storage element.

Conventionally, as a non-aqueous storage element, a positive electrode containing a positive electrode active material such as a lithium cobalt composite oxide, a negative electrode containing a negative electrode active material such as carbon, and a non-aqueous electrolyte solution in which a lithium salt is dissolved in a non-aqueous solvent. Lithium-ion secondary batteries having the above are often used.

In recent years, non-aqueous power storage elements have been used in a wide range of applications from portable devices to electric vehicles, and there is a demand for non-aqueous power storage elements having a high input / output density.

As a non-aqueous power storage element having a high input / output density, a dual carbon battery (DCB) using carbon as a positive electrode active material and a negative electrode active material is known.

In the DCB, the anion in the non-aqueous electrolyte solution is inserted or desorbed into the positive electrode active material, and the lithium ions in the non-aqueous electrolyte solution are inserted or desorbed into the negative electrode active material to perform charging and discharging. At this time, since ions are inserted (intercalated) between the positive electrode active material and the negative electrode active material, the battery resistance is very small and the input / output density is very large.

ＤＣＢの放電容量は、正極活物質のアニオンが挿入されている量、正極活物質のアニオンを脱離することが可能な可能量、負極活物質のカチオンが挿入されている量、負極活物質のカチオンを脱離することが可能な量、非水電解液中のアニオン量及びカチオン量で決まる。

The discharge capacity of the DCB is the amount of the anion of the positive electrode active material inserted, the amount of possible desorption of the anion of the positive electrode active material, the amount of the cation of the negative electrode active material inserted, and the amount of the negative electrode active material. It is determined by the amount of cations that can be desorbed, the amount of anions in the non-aqueous electrolyte solution, and the amount of cations.

In order to increase the discharge charge capacity of the non-aqueous power storage element, a large amount of ions in the non-aqueous electrolytic solution is required. Therefore, a large amount of non-aqueous electrolyte solution is required at a concentration of ions of about 1 M in the non-aqueous electrolyte solution normally used in lithium ion secondary batteries.

Patent Document 1 includes a positive electrode containing a first active material capable of occluding and releasing anions, a negative electrode, and an electrolyte containing a salt of a cation and an anion, and the anion is [(FSO _{2 ) 2} ). N] ^- a non-aqueous electrolyte secondary battery is disclosed which.

However, there is a problem that the discharge / charge capacity under high temperature conditions is low.

That is, an object of the present invention is to provide a non-aqueous power storage element having a high discharge / charge capacity under high temperature conditions.

In order to achieve the above object, one aspect of the present invention includes a positive electrode containing a positive electrode active material capable of inserting or removing an anion, and a negative electrode active material capable of inserting or removing a cation. A non-aqueous storage element having a negative electrode and a non-aqueous electrolyte solution in which an electrolyte salt is dissolved in a non-aqueous solvent and having an operating temperature of 60 ° C. or higher. The non- aqueous electrolyte solution is the electrolyte. the concentration of salt is Ri der than 5.0 M, the electrolyte salt comprises an imide-based anion.

According to the present invention, it is possible to provide a non-aqueous power storage element having a high discharge / charge capacity under high temperature conditions.

It is a schematic diagram which shows an example of the non-aqueous power storage element of this embodiment. It is a figure which shows the change of the discharge capacity with respect to the number of charge / discharge cycles of the non-aqueous power storage element of Example 1-1.

(Non-water storage element)
The non-aqueous storage element of the present embodiment includes a positive electrode containing a positive electrode active material capable of inserting and removing anions, a negative electrode containing a negative electrode active material capable of inserting and removing cations, and non-water. It has a non-aqueous electrolyte solution in which an electrolyte salt is dissolved in a solvent. The non-aqueous power storage element of the present embodiment preferably has a separator, and further has other members, if necessary.

Hereinafter, the positive electrode, the negative electrode, the non-aqueous electrolytic solution, and the separator of the non-aqueous power storage element of the present embodiment will be sequentially described.

<Positive electrode>
The positive electrode is not particularly limited as long as it contains a positive electrode active material, and can be appropriately selected depending on the intended purpose. For example, a positive electrode provided with a positive electrode material layer containing a positive electrode active material on a positive electrode current collector. And so on.

The shape of the positive electrode is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a flat plate shape.

<< Positive electrode material layer >>
The positive electrode material layer contains a positive electrode active material, and further contains a binder, a thickener, a conductive agent, and the like, if necessary.

The average thickness of the positive electrode material layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 20 μm to 300 μm, and more preferably 40 μm to 200 μm. When the average thickness of the positive electrode material layer is 20 μm or more, the energy density of the non-aqueous power storage element is improved, and when it is 300 μm or less, the load characteristics of the non-aqueous power storage element are improved.

-Positive electrode active material-
The positive electrode active material is not particularly limited as long as it is a substance capable of reversibly inserting or removing anions, and can be appropriately selected depending on the intended purpose. For example, a carbonaceous material or a highly conductive material. Examples include molecules. Among these, carbonaceous materials are particularly preferable because of their high energy density.

Examples of the conductive polymer include polyaniline, polypyrrole, poly (p-phenylene), and the like.

Examples of the carbonaceous material include graphite (graphite) such as coke, artificial graphite, and natural graphite, and pyrolyzed products of organic substances under various pyrolysis conditions. Among these, artificial graphite, natural graphite, and soft carbon are particularly preferable.

The carbonaceous material preferably has high crystallinity.

The crystallinity of the carbonaceous material can be evaluated by X-ray diffraction, Raman analysis and the like.

For the carbonaceous material, for example, in a powder X-ray diffraction pattern using CuKα rays, the diffraction peak intensity I _{2θ = 22.3 ° at 2θ = 22.3 °} and the diffraction peak intensity I _{2θ at 2θ = 26.4 °. = 26.4 °} of the intensity ratio _{I 2θ = 22.3 ° / I 2θ} = 26.4 ° is preferably not more than 0.4.

Graphite is preferably is preferably a BET specific surface area by nitrogen adsorption is ^{1m 2} / ^g~100m 2 / g, a median diameter determined by laser diffraction-scattering method is approximately 0.1-100 [mu] m.

Soft carbon is a general term for carbon in which a hexagonal network composed of carbon atoms easily forms a regular laminated structure by heat treatment in an inert atmosphere, for example.

_{The soft carbon has a crystal structure in which the average spacing d (002)} of the (002) plane is preferably 3.50 Å or less, more preferably 3.35 Å to 3.45 Å when heat-treated in an inert atmosphere. Carbon is used to form.

Examples of the raw material for soft carbon include easily graphitized coke such as petroleum pitch, coal-based pitch, coke, and anthracene. These may be used alone or in combination of two or more.

-Binder-
The binder is not particularly limited as long as it is a material stable to the solvent used when producing the positive electrode and the non-aqueous electrolytic solution, and can be appropriately selected depending on the purpose. For example, polyvinylidene fluoride (PVDF). ), Fluorine-based binder such as polytetrafluoroethylene (PTFE), acrylic-based binder, styrene-butadiene rubber (SBR), isoprene rubber and the like. These may be used alone or in combination of two or more.

-Thickener-
Examples of the thickener include carboxymethyl cellulose (CMC), methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, sodium alginate and the like. These may be used alone or in combination of two or more.

-Conducting agent-
Examples of the conductive agent include metal materials such as copper and aluminum, and carbonaceous materials such as carbon black, ketjen black, and acetylene black. These may be used alone or in combination of two or more.

<< Positive Electrode Current Collector >>
The material, shape, size, and structure of the positive electrode current collector are not particularly limited and can be appropriately selected depending on the intended purpose.

The material of the positive electrode current collector is not particularly limited as long as it is a conductive material, and can be appropriately selected depending on the intended purpose. Examples thereof include stainless steel, nickel, aluminum, copper, titanium, and tantalum. .. Among these, stainless steel and aluminum are particularly preferable.

The shape of the positive electrode current collector is not particularly limited and may be appropriately selected depending on the intended purpose.

The size of the positive electrode current collector is not particularly limited as long as it can be used for a non-aqueous power storage element, and can be appropriately selected depending on the intended purpose.

<< Method of manufacturing positive electrode >>
For the positive electrode, a binder, a thickener, a conductive agent, a solvent, etc. are added to the positive electrode active material as necessary, and a slurry-like coating liquid for the positive electrode material layer is applied onto the positive electrode current collector. It can be produced by drying to form a positive electrode material layer.

The solvent is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an aqueous solvent and an organic solvent.

Examples of the aqueous solvent include water and alcohol.

Examples of the organic solvent include N-methyl-2-pyrrolidone (NMP), toluene and the like.

If necessary, the positive electrode composition obtained by adding a binder, a thickener, a conductive agent, or the like to the positive electrode active material can be roll-molded to form a sheet electrode, or compression-molded to form a pellet electrode. ..

<Negative electrode>
The negative electrode is not particularly limited as long as it contains a negative electrode active material, and can be appropriately selected depending on the intended purpose. For example, a negative electrode having a negative electrode material layer containing a negative electrode active material on a negative electrode current collector, etc. Can be mentioned.

The shape of the negative electrode is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a flat plate shape.

<< Negative electrode material layer >>
The negative electrode material layer contains a negative electrode active material, and further contains a binder, a conductive agent, and the like, if necessary.

The average thickness of the negative electrode material layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 μm to 450 μm, and more preferably 20 μm to 200 μm. When the average thickness of the negative electrode material layer is 10 μm or more, the cycle characteristics of the non-aqueous power storage element are improved, and when it is 450 μm or less, the energy density of the non-aqueous power storage element is improved.

-Negative electrode active material-
The negative electrode active material is not particularly limited as long as it is a material capable of reversibly inserting or removing cations, and can be appropriately selected depending on the intended purpose. For example, alkali metal ions or alkaline earth. Metal oxides capable of reversibly inserting or removing metal ions; metals or alloys thereof capable of alloying with alkali metals and alkaline earth metals, composite alloy compounds; carbonaceous materials with high specific surface area Examples thereof include non-reactive electrodes due to physical adsorption of ions such as. Among these, a substance capable of reversibly inserting or removing lithium ions is preferable in terms of energy density, and a non-reactive electrode is more preferable in terms of cycle characteristics.

Specific examples of the negative electrode active material include carbonaceous materials, metal oxides capable of reversibly inserting or removing lithium ions such as lithium, antimony tin oxide, and silicon monoxide, aluminum, tin, and silicon. , A metal that can be alloyed with lithium such as zinc or an alloy thereof, a metal that can be alloyed with lithium and a composite alloy compound of the alloy and lithium, a metal titrated metal such as cobalt titrated lithium Examples include lithium. These may be used alone or in combination of two or more. Among these, carbonaceous materials are particularly preferable from the viewpoint of safety and cost.

-Binder-
The binder is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a fluorine-based binder such as polyvinylidene fluoride (PVDF) or polytetrafluoroethylene (PTFE), ethylene-propylene-butadiene rubber (EPBR) ), Styrene-butadiene rubber (SBR), isoprene rubber, carboxymethyl cellulose (CMC), and the like. These may be used alone or in combination of two or more.

-Conducting agent-
Examples of the conductive agent include metal materials such as copper and aluminum, and carbonaceous materials such as carbon black and acetylene black. These may be used alone or in combination of two or more.

-Negative electrode current collector-
The material, shape, size, and structure of the negative electrode current collector are not particularly limited and can be appropriately selected depending on the intended purpose.

The material of the negative electrode current collector is not particularly limited as long as it is a conductive material, and can be appropriately selected depending on the intended purpose. Examples thereof include stainless steel, nickel, aluminum, and copper. Among these, stainless steel and copper are particularly preferable.

The shape of the negative electrode current collector is not particularly limited and may be appropriately selected depending on the intended purpose.

The size of the negative electrode current collector is not particularly limited as long as it can be used for a non-aqueous power storage element, and can be appropriately selected depending on the intended purpose.

-How to make a negative electrode-
The negative electrode is prepared by adding a binder, a conductive agent, a solvent, etc. to the negative electrode active material as necessary, applying a slurry coating liquid for the negative electrode material layer on the negative electrode current collector, and then drying the negative electrode. It can be produced by forming a negative electrode material layer.

As the solvent, the same solvent as in the method for producing a positive electrode can be used.

If necessary, the negative electrode composition obtained by adding a binder, a conductive agent, or the like to the negative electrode active material can be roll-molded to form a sheet electrode, or compression-molded to form a pellet electrode.

Further, a thin film of the negative electrode active material can be formed on the negative electrode current collector by a method such as thin film deposition, sputtering, or plating to form a negative electrode material.

<Non-aqueous electrolyte>
In the non-aqueous electrolyte solution, an electrolyte salt is dissolved in a non-aqueous solvent.

The concentration of the electrolyte salt in the non-aqueous electrolyte solution is 5 M or more, preferably 3 M or more. When the concentration of the electrolyte salt in the non-aqueous electrolyte solution is less than 5 M, the discharge / charge capacity of the non-aqueous power storage element under high temperature conditions becomes low.

The non-aqueous power storage element of the present embodiment preferably has an operating temperature of 40 ° C. or higher.

<< Non-aqueous solvent >>
The non-aqueous solvent is not particularly limited and may be appropriately selected depending on the intended purpose, but an aprotic organic solvent is preferably used.

As the aprotic organic solvent, a carbonate-based organic solvent such as a cyclic carbonate or a chain carbonate is used. At this time, the aprotic organic solvent preferably contains a chain carbonate and a cyclic carbonate.

Examples of the chain carbonate include dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), and methyl propionate (MP). Of these, dimethyl carbonate (DMC) is preferred.

Examples of the cyclic carbonate include propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate (BC), vinylene carbonate (VC) and the like. Among these, ethylene carbonate (EC) is preferable.

The content of the chain carbonate in the non-aqueous solvent is preferably 70.0% by mass to 99.9% by mass, more preferably 70% by mass to 80% by mass. When the content of the chain carbonate in the non-aqueous solvent is 70.0% by mass or more, the viscosity is low, so that the non-aqueous electrolyte solution easily permeates the electrode and ion diffusion is easy. On the other hand, when the content of the chain carbonate in the non-aqueous solvent is 99.9% by mass or less, the electrolyte salt is easily dissolved in the non-aqueous solvent at a high concentration.

The content of the cyclic carbonate in the non-aqueous solvent is preferably 0.1% by mass to 30.0% by mass, more preferably 20% by mass to 30% by mass. When the content of the cyclic carbonate in the non-aqueous solvent is 0.1% by mass or more, the electrolyte salt is easily dissolved in the non-aqueous solvent at a high concentration. On the other hand, when the content of the cyclic carbonate in the non-aqueous solvent is 30.0% by mass or less, the viscosity is low, so that the non-aqueous electrolytic solution easily permeates the electrode and ion diffusion is easy.

As the non-aqueous solvent, an ester-based organic solvent such as a cyclic ester or a chain ester, an ether-based organic solvent such as a cyclic ether or a chain ether, or the like can be used, if necessary.

Examples of the cyclic ester include γ-butyrolactone (γBL), 2-methyl-γ-butyrolactone, acetyl-γ-butyrolactone, γ-valerolactone and the like.

Examples of the chain ester include propionic acid alkyl ester, malonic acid dialkyl ester, acetate alkyl ester (methyl acetate (MA), ethyl acetate, etc.), formic acid alkyl ester (methyl formate (MF), ethyl formate, etc.) and the like. Be done.

Examples of the cyclic ether include tetrahydrofuran, alkyl tetrahydrofuran, alkoxytetrahydrofuran, dialkoxytetrahydrofuran, 1,3-dioxolane, alkyl-1,3-dioxolane, 1,4-dioxolane and the like.

Examples of the chain ether include 1,2-dimethosicietan (DME), diethyl ether, ethylene glycol dialkyl ether, diethylene glycol dialkyl ether, triethylene glycol dialkyl ether, tetraethylene glycol dialkyl ether and the like.

<< Electrolyte salt >>
The electrolyte salt is not particularly limited as long as it is a compound that dissolves in a non-aqueous solvent and exhibits high ionic conductivity, but the anion constituting the electrolyte salt is preferably an imide-based anion.

Examples of the cation constituting the electrolyte salt include alkali metal ion, alkaline earth metal ion, tetraalkylammonium ion, and spirotic quaternary ammonium ion.

Examples of the imide-based anion constituting the electrolyte salt include (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (CF ₂ F ₅ SO ₂ ) ₂ N ⁻ , and (FSO _2). ) ₂ N ^{− and the} like.

Examples of anions other than the imide-based anions constituting the electrolyte salt include Cl ⁻ , Br ⁻ , I ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , and CF ₃ SO ₃ ^−. And so on.

Among the electrolyte salts, the lithium salt is particularly preferable from the viewpoint of improving the discharge / charge capacity of the non-aqueous power storage element.

Examples of the lithium salt of the imide-based anion include lithium bistrifluoromethylsulfonylimide (LiN (CF ₃ SO ₂ ) ₂ ), lithium bispentafluoroethanesulfonylimide (LiN (C ₂ F ₅ SO ₂ ) ₂ ), and lithium bis. Examples thereof include furfluoroethylsulfonylimide (LiN (CF ₂ F ₅ SO ₂ ) ₂ ) and lithium bis (fluorosulfonyl) imide (LiN (FSO ₂ ) _2). These may be used alone or in combination of two or more.

<Separator>
The separator is provided between the positive electrode and the negative electrode in order to prevent a short circuit between the positive electrode and the negative electrode.

The material, shape, size, and structure of the separator are not particularly limited and may be appropriately selected depending on the intended purpose.

Examples of the separator include paper such as kraft paper, vinylon mixed paper, synthetic pulp mixed paper, polyolefin non-woven fabric such as cellophane, polyethylene graft film, polypropylene melt flow non-woven fabric, polyamide non-woven fabric, and glass fiber non-woven fabric.

The separator preferably has a porosity of 50% or more from the viewpoint of retaining the non-aqueous electrolytic solution.

As the shape of the separator, a non-woven fabric type is preferable to a thin film type having micropores (micropores) because of its high porosity.

The average thickness of the separator is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 20 μm to 100 μm. When the average thickness of the separator is 20 μm or more, the holding amount of the non-aqueous electrolytic solution is large, and when it is 100 μm or less, the energy density of the non-aqueous power storage element is improved.

In order to prevent positive and negative short circuits due to precipitation of alkali metal and alkaline earth metal on the negative electrode side, a microporous film (micropore film) with an average thickness of 30 μm or less is arranged on the negative electrode side as a separator, and an average thickness of 20 μm on the positive electrode side. It is preferable to arrange a non-woven film having a pore size of about 100 μm and a pore ratio of 50% or more.

Examples of the shape of the separator include a sheet shape and the like.

The size of the separator is not particularly limited as long as it can be used for a non-aqueous power storage element, and can be appropriately selected depending on the intended purpose.

<Other parts>
The other members are not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include an outer can and a lead wire.

<Manufacturing method of non-aqueous power storage element>
The non-aqueous power storage element of the present embodiment can be manufactured, for example, by assembling a positive electrode, a negative electrode, a non-aqueous electrolytic solution, and a separator into an appropriate shape. At this time, if necessary, other members such as an outer can can be further used.

The method for assembling the non-aqueous power storage element is not particularly limited, and can be appropriately selected from the commonly adopted methods.

The non-aqueous power storage element of the present embodiment is not particularly limited and may be appropriately selected depending on the intended purpose, but the maximum voltage during charging / discharging is preferably 4.5V to 6.0V. When the maximum voltage during charging and discharging of the non-aqueous power storage element is 4.5 V or more, the anion can be sufficiently inserted, so that the discharge / charge capacity of the non-aqueous power storage element is improved and is 6.0 V or less. , Non-aqueous solvent and electrolyte salt are less likely to decompose and deteriorate.

<Shape of non-aqueous power storage element>
The shape of the non-aqueous power storage element of the present embodiment is not particularly limited and may be appropriately selected from various generally adopted shapes according to the application. For example, a laminated type or a sheet. Examples thereof include a cylinder type in which electrodes and separators are spirally formed, a cylinder type having an inside-out structure in which pellet electrodes and separators are combined, and a coin type in which pellet electrodes and separators are laminated.

FIG. 1 shows an example of the non-aqueous power storage element of the present embodiment.

In the non-aqueous power storage element 10, the positive electrode 11, the negative electrode 12, and the separator 13 are housed in the outer can 14, and the separator 13 is filled with the non-aqueous electrolytic solution. Further, the positive electrode 11 and the negative electrode 12 are provided with lead wires 15 and 16, respectively.

<Applications of non-aqueous power storage elements>
The non-aqueous power storage element of the present embodiment is not particularly limited and can be used for various purposes. For example, a notebook computer, a pen input computer, a mobile computer, an electronic book player, a mobile phone, a mobile fax, and a mobile copy. , Mobile printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, mini disk, transceiver, electronic notebook, calculator, memory card, portable tape recorder, radio, backup power supply, motor, lighting equipment, toys, game equipment , Watches, strobes, cameras, electric bicycles, electric tools, etc.

Hereinafter, examples of the present invention will be described, but the present invention is not limited to these examples.

<Production example of positive electrode>
-Preparation of positive electrode A-
After adding water to 10.0 g of graphite powder KS-6 (manufactured by TIMCAL) and 0.75 g of a conductive agent (acetylene black) as a positive electrode active material and kneading them, carboxymethyl cellulose (CMC) as a thickener. 19 g of a 2 mass% aqueous solution of No. 1 was added and kneaded. Subsequently, 0.75 g of binder TRD-202A (manufactured by JSR Corporation) was added and kneaded to prepare a slurry for the positive electrode material layer.

Here, the graphite powder KS-6 (manufactured by TIMCAL) has a BET specific surface area of 20 m ² / g due to nitrogen adsorption, and has a median diameter of 3 measured by a laser diffraction particle size distribution meter SALD-2200 (manufactured by Shimadzu Corporation). It was .4 μm.

Next, a slurry for a positive electrode material layer was applied onto an aluminum foil as a positive electrode current collector, and then vacuum dried at 120 ° C. for 5 minutes to form a positive electrode material layer. The aluminum foil on which the positive electrode material layer was formed was punched into a round shape having a diameter of 16 mm to prepare a positive electrode A. At this time, the content of graphite powder KS-6 (manufactured by TIMCAL) in the positive electrode material layer formed on the aluminum foil having a diameter of 16 mm was 20 mg.

-Preparation of positive electrode B-
After adding water to 10.0 g of soft carbon SMC (manufactured by Hitachi Kasei Kogyo Co., Ltd.) and 0.75 g of conductive agent (acetylene black) as a positive electrode active material and kneading them, carboxymethyl cellulose (CMC) as a thickener 19 g of a 2 mass% aqueous solution of No. 1 was added and kneaded. Subsequently, 0.75 g of binder TRD-202A (manufactured by JSR Corporation) was added and kneaded to prepare a slurry for the positive electrode material layer.

Here, the soft carbon SMC (manufactured by Hitachi Kasei Kogyo Co., Ltd.) has a BET specific surface area of 2.7 m ² / g due to nitrogen adsorption, and has a median diameter measured by a laser diffraction particle size distribution meter SALD-2200 (manufactured by Shimadzu Corporation). Was 15 μm, and the tap density was 910 kg / m ³ .

Next, a slurry for a positive electrode material layer was applied onto an aluminum foil as a positive electrode current collector, and then vacuum dried at 120 ° C. for 5 minutes to form a positive electrode material layer. The aluminum foil on which the positive electrode material layer was formed was punched into a round shape having a diameter of 16 mm to prepare a positive electrode B. At this time, the content of soft carbon SMC (manufactured by Hitachi Kasei Kogyo Co., Ltd.) in the positive electrode material layer formed on the aluminum foil having a diameter of 16 mm was 20 mg.

<Manufacturing example of negative electrode>
-Manufacturing of negative electrode A-
Water is added to 10 g of graphite MAGD (manufactured by Hitachi Kasei Kogyo Co., Ltd.) and 0.5 g of a conductive agent (acetylene black) as a negative electrode active material and kneaded, and then 2 masses of carboxymethyl cellulose (CMC) as a thickener. 10 g of% aqueous solution was added and kneaded. Subsequently, 0.6 g of a 50.2 mass% aqueous solution of Binder EX1215 (manufactured by Denki Kagaku Kogyo Co., Ltd.) was added to prepare a slurry for the negative electrode material layer.

Here, graphite MAGD (manufactured by Hitachi Kasei Kogyo Co., Ltd.) has a BET specific surface area of 4.5 m ² / g due to nitrogen adsorption, and has a median diameter measured by a laser diffraction particle size distribution meter SALD-2200 (manufactured by Shimadzu Corporation). It was 20 μm and the tap density was 630 kg / m ³ .

Next, a slurry for a negative electrode material layer was applied to a copper foil as a negative electrode current collector, and then vacuum dried at 120 ° C. for 5 minutes to form a negative electrode material layer. The copper foil on which the negative electrode material layer was formed was punched into a round shape having a diameter of 16 mm to prepare a negative electrode A. At this time, the content of graphite MAGD (manufactured by Hitachi Kasei Kogyo Co., Ltd.) in the negative electrode material layer formed on the copper foil having a diameter of 16 mm was 20 mg.

<Production example of non-aqueous electrolyte solution>
-Preparation of non-aqueous electrolyte solution A-
Lithium bistrifluoromethylsulfonylimide (LiTFSI) was dissolved in a mixed solution of diethyl carbonate (DEC) and ethylene carbonate (EC) at a mass ratio of 70:30 to prepare 20 mL of 7.0 M non-aqueous electrolyte solution A. ..

-Preparation of non-aqueous electrolytes B and C-
20 mL of 7.0 M non-aqueous electrolytes B and C were prepared in the same manner as the non-aqueous electrolyte A except that ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) were used instead of DEC, respectively.

-Preparation of non-aqueous electrolyte D-
LiTFSI was dissolved in a mixed solution of DEC and EC at a mass ratio of 90:10 to prepare 20 mL of 5.0 M non-aqueous electrolytic solution D.

-Preparation of non-aqueous electrolytes E and F-
20 mL of 5.0 M non-aqueous electrolytes E and F were prepared in the same manner as the non-aqueous electrolyte D except that EMC and DMC were used instead of DEC, respectively.

-Preparation of non-aqueous electrolytes G, H, I-
20 mL of non-aqueous electrolytes G, H, and I were prepared in the same manner as the non-aqueous electrolytes A, B, and C, respectively, except that the concentration of LiTFSI was changed to 1.0 M.

-Preparation of non-aqueous electrolytes J, K, L-
20 mL of non-aqueous electrolytes J, K, and L were prepared in the same manner as the non-aqueous electrolytes A, B, and C, respectively, except that the concentration of LiTFSI was changed to 5.0 M.

-Preparation of non-aqueous electrolyte M-
20 mL of the non-aqueous electrolyte M was prepared in the same manner as the non-aqueous electrolyte C except that the concentration of LiTFSI was changed to 2.0 M.

Table 1 shows the composition of the non-aqueous electrolyte solution AM.

＜正極Ａの放電容量＞
コイン缶中に、正極Ａ、平均厚みが２５μｍのセルロースからなるセパレータ、非水電解液Ｍ及び対極としての、平均厚みが２００μｍのリチウム電極（本庄金属社製）を収容し、非水系蓄電素子を作製した。

<Discharge capacity of positive electrode A>
A positive electrode A, a separator made of cellulose having an average thickness of 25 μm, a non-aqueous electrolyte M, and a lithium electrode (manufactured by Honjo Metal Co., Ltd.) having an average thickness of 200 μm as a counter electrode are housed in a coin can to accommodate a non-aqueous power storage element. Made.

At room temperature (25 ° C.), was charged at a constant current of 1 mA / cm ² until the charge voltage 5.2V nonaqueous electricity storage device, and discharge at a constant current of 1 mA / cm ² up to 3.0 V, the initial charge and discharge Was carried out. Then, after charging the non-aqueous power storage device to 1 mA / cm ² constant current after the initial charge and discharge to 5.2V, it was performed twice a charge-discharge cycle to discharge at a constant current of 1 mA / cm ² to 3.0V .. When the discharge capacity per unit area of the positive electrode A at this time was measured, it was 0.85 mAh / cm ² .

The discharge capacity per unit area of the positive electrode A was measured using a charge / discharge measuring device TOSCAT3001 (manufactured by Toyo System Co., Ltd.).

<Discharge capacity of positive electrode B>
The discharge capacity per unit area of the positive electrode B was measured in the same manner as the discharge capacity of the positive electrode A except that the positive electrode B was used instead of the positive electrode A, and it was ^{0.81 mAh / cm 2.}

<Discharge capacity of negative electrode A>
A negative electrode A, a separator made of cellulose having an average thickness of 25 μm, a non-aqueous electrolytic solution M, and a lithium electrode (manufactured by Honjo Metal Co., Ltd.) having an average thickness of 200 μm as a counter electrode are housed in a coin can to accommodate a non-aqueous power storage element. Made.

At room temperature (25 ° C.), was charged at a constant current of 2 mA / cm ² until the charge voltage 1.7V nonaqueous electricity storage device, and discharge at a constant current of 2 mA / cm ² to 3.5V, then the initial charge and discharge Was carried out. Then, after charging the non-aqueous power storage device to 2 mA / cm ² constant current after the initial charge and discharge to 1.7V, it was performed twice a charge-discharge cycle to discharge at a constant current of 2 mA / cm ² to 3.5V .. When the discharge capacity per unit area of the negative electrode A at this time was measured, it was 0.79 mAh / cm ² .

The discharge capacity per unit area of the negative electrode A was measured using a charge / discharge measuring device TOSCAT3001 (manufactured by Toyo System Co., Ltd.).

[Example 1-1]
A positive electrode A, a negative electrode A, a glass fiber separator (manufactured by ADVANTEC) having an average thickness of 0.38 mm, and a non-aqueous electrolyte solution A are placed in a coin can 2032 type (manufactured by Hosen Co., Ltd.), and then the can is crimped. A non-aqueous power storage element was manufactured by caulking with (manufactured by Hosensha).

[Examples 1-1 to 1-9]
A non-aqueous power storage element was produced in the same manner as in Example 1-1, except that the non-aqueous electrolytic solutions B to F and J to L were used instead of the non-aqueous electrolytic solution A, respectively.

[Comparative Examples 1-1 to 1-3]
A non-aqueous power storage element was produced in the same manner as in Example 1-1, except that the non-aqueous electrolytic solutions G to I were used instead of the non-aqueous electrolytic solution A, respectively.

Next, the initial charge capacity and the initial discharge capacity of the non-aqueous power storage elements of Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-3 were measured.

<Initial charge capacity and initial discharge capacity>
25 ° C., at 60 ° C., was charged to a charge termination voltage 5.2V at a constant current of 1 mA / cm ² in a nonaqueous electricity storage device, and discharge at a constant current of 1 mA / cm ² up to 3.0 V, the initial charge and discharge Was carried out. Then, after charging the non-aqueous power storage device to 1 mA / cm ² constant current after the initial charge and discharge to 5.2V, and discharged at a constant current of 1 mA / cm ² until 3.0 V, it carried an initial charge and discharge , The initial discharge capacity and the initial charge capacity were measured.

The initial charge capacity and the initial discharge capacity of the non-aqueous power storage element were measured using a charge / discharge measuring device TOSCAT3001 (manufactured by Toyo System Co., Ltd.).

Table 2 shows the measurement results of the initial charge capacity and the initial discharge capacity of the non-aqueous power storage element.

表２から、実施例１−１〜１−９の非水系蓄電素子は、６０℃における初回充電容量及び初回放電容量が高いことがわかる。

From Table 2, it can be seen that the non-aqueous power storage elements of Examples 1-1 to 1-9 have high initial charge capacity and initial discharge capacity at 60 ° C.

On the other hand, the non-aqueous power storage elements of Comparative Examples 1-1 to 1-3 have low initial charge capacity and initial discharge capacity at 60 ° C.

Next, the maintenance rate of the discharge capacity of the non-aqueous power storage element of Examples 1-1 to 1-9 at 60 ° C. was measured.

<Maintenance rate of discharge capacity>
In 60 ° C., was charged to a charge termination voltage 5.2V at a constant current of 1 mA / cm ² in a nonaqueous electricity storage device, and discharge at a constant current of 1 mA / cm ² up to 3.0 V, were carried out initial charge-discharge .. Then, after charging the non-aqueous power storage device to 1 mA / cm ² constant current after the initial charge and discharge to 5.2V, the charge-discharge cycle to discharge at a constant current of 1 mA / cm ² to 3.0V it was performed 30 times , The maintenance rate of the discharge capacity was calculated from the first and 30th discharge capacities.

Table 3 shows the measurement results of the maintenance rate of the discharge capacity of the non-aqueous power storage element at 60 ° C.

表３から、実施例１−１〜１−９の非水系蓄電素子は、６０℃における放電容量の維持率が高いことがわかる。

From Table 3, it can be seen that the non-aqueous power storage elements of Examples 1-1 to 1-9 have a high retention rate of discharge capacity at 60 ° C.

FIG. 2 shows a change in discharge capacity with respect to the number of charge / discharge cycles of the non-aqueous power storage element of Example 1-1.

[Examples 2-1 to 2-9, Comparative Examples 2-1 to 2-3]
Non-aqueous power storage elements were produced in the same manner as in Examples 1-1 to 1-9 and Comparative Examples 1-1 to 1-3, respectively, except that the positive electrode B was used instead of the positive electrode A.

Next, the initial charge capacity and the initial discharge capacity of the non-aqueous power storage element were measured.

Table 4 shows the measurement results of the initial charge capacity and the initial discharge capacity of the non-aqueous power storage element.

表４から、実施例２−１〜２−９の非水系蓄電素子は、６０℃における初回充電容量及び初回放電容量が高いことがわかる。

From Table 4, it can be seen that the non-aqueous power storage elements of Examples 2-1 to 2-9 have high initial charge capacity and initial discharge capacity at 60 ° C.

On the other hand, the non-aqueous power storage elements of Comparative Examples 2-1 to 2-3 have low initial charge capacity and initial discharge capacity at 60 ° C.

Next, the maintenance rate of the discharge capacity of the non-aqueous power storage element of Examples 2-1 to 2-9 at 60 ° C. was measured.

Table 5 shows the measurement results of the maintenance rate of the discharge capacity of the non-aqueous power storage element at 60 ° C.

表５から、実施例２−１〜２−９の非水系蓄電素子は、６０℃における放電容量の維持率が高いことがわかる。

From Table 5, it can be seen that the non-aqueous power storage elements of Examples 2-1 to 2-9 have a high retention rate of discharge capacity at 60 ° C.

10 Non-aqueous power storage element 11 Positive electrode 12 Negative electrode 13 Separator 14 Exterior can 15, 16 Leader wire

Japanese Unexamined Patent Publication No. 2013-251668

Claims (7)

A positive electrode containing a positive electrode active material capable of inserting or removing anions, and a positive electrode
A negative electrode containing a negative electrode active material capable of inserting or removing cations, and a negative electrode
It has a non-aqueous electrolyte solution in which an electrolyte salt is dissolved in a non-aqueous solvent.
A non-aqueous power storage element having an operating temperature of 60 ° C. or higher.
The non-aqueous electrolyte, the concentration of the electrolyte salt Ri der than 5.0 M,
The electrolyte salt is a non-aqueous storage device containing an imide-based anion. The non-aqueous power storage element according to claim 1, wherein the maximum voltage during charging / discharging is 4.5 V or more and 6.0 V or less. The non-aqueous solvent contains a chain carbonate and a cyclic carbonate, and contains
The content of the chain carbonate is 70.0% by mass or more and 99.9% by mass or less.
The non-aqueous power storage device according to claim 1 or 2 , wherein the content of the cyclic carbonate is 0.1% by mass or more and 30.0% by mass or less. The non-aqueous power storage device according to claim 3 , wherein the cyclic carbonate contains ethylene carbonate. The non-aqueous power storage device according to any one of claims 1 to 4 , wherein the electrolyte salt contains a lithium salt. The non-aqueous power storage element according to any one of claims 1 to 5 , wherein the cathode active material is a carbonaceous material. The non-aqueous power storage element according to any one of claims 1 to 6 , wherein the negative electrode active material is a carbonaceous material.

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