JP7034549B2 - Non-aqueous electrolyte solution and non-aqueous electrolyte battery using it - Google Patents

Description

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

Non-aqueous electrolyte batteries such as lithium secondary batteries are being put to practical use in a wide range of applications from so-called consumer power sources such as mobile phones and notebook computers to in-vehicle power sources for driving such as automobiles. However, in recent years, the demand for higher performance of non-aqueous electrolyte batteries has been increasing, and in particular, various battery characteristics such as high capacity, low temperature use characteristics, high temperature storage characteristics, cycle characteristics, and safety during overcharging have been increasing. Is requested to be improved.

The electrolyte used in a non-aqueous electrolyte battery is usually mainly composed of an electrolyte and a non-aqueous solvent. The main components of the non-aqueous solvent include cyclic carbonates such as ethylene carbonate and propylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and ethylmethyl carbonate; cyclic carboxylic acid esters such as γ-butyrolactone and γ-valerolactone. It is used.

Various studies have been conducted on non-aqueous solvents, electrolytes, and additives in order to improve battery characteristics such as load characteristics, cycle characteristics, and storage characteristics of such non-aqueous electrolyte batteries, and to improve battery safety during overcharging. It has been done.
Patent Documents 1 and 2 propose a method of adding various aromatic compounds such as aromatic carboxylic acid esters to an electrolytic solution together with other additives, and solve the problems of safety improvement and durability during overcharging to some extent. Is disclosed.

International Publication 2015/11676 Japanese Unexamined Patent Publication No. 2015-18667

According to the studies by the present inventors, the aromatic ester compounds as described in Patent Documents 1 and 2 have a lower oxidation potential than other electrolyte constituents, and therefore, within a normal battery operating range. It was found that it was oxidized to form a film on the positive electrode and became a resistance component. When such an aromatic ester compound is used in combination with a positive electrode protective agent such as succinonitrile, oxidation is suppressed to some extent, but the capacity and rate characteristics after the durability test are particularly deteriorated, and the battery is still satisfactory. It wasn't a thing.
In view of the above problems, it is an object of the present invention to provide a non-aqueous electrolyte solution having excellent rate characteristics after a battery durability test while using an aromatic ester, and a non-aqueous electrolyte battery using the same. ..

The present inventors have solved the above problems by incorporating an aromatic carboxylic acid ester having a specific substituent on the benzene ring and binding to an ester group via a specific structure and adiponitrile in a non-aqueous electrolytic solution. We have found that it can be solved and have completed the present invention.
That is, the gist of the present invention is as shown below.

[1] A non-aqueous electrolyte solution for a non-aqueous electrolyte battery having a positive electrode and a negative electrode capable of storing and releasing metal ions, wherein the non-aqueous electrolyte solution is represented by the following formula (1) together with an electrolyte and a non-aqueous solvent. A non-aqueous electrolyte solution containing an aromatic carboxylic acid ester and further containing an adiponitrile.

(In the formula (1), R ¹ represents a saturated hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and R ² and R ³ each independently have a fluorine atom or a substituent. It may be a hydrocarbon group having 1 to 12 carbon atoms and may be bonded to each other to form a ring. A may be substituted with a hydrocarbon group having 1 to 12 carbon atoms or a fluorine atom. It is a good alkoxy group having 1 to 12 carbon atoms, a fluorine atom, or a substituent containing a fluorine atom, and m is an integer of 1 to 5. When m is 2 or more, a plurality of A's may be the same as each other. They may be very different, or the two A's may be bonded to each other to form a ring that condenses with a benzene ring having an A.)

[2] In the formula (1), A is a hydrocarbon group having 4 to 12 carbon atoms, and the carbon atom bonded to the benzene ring of the hydrocarbon group is a quaternary carbon atom. The non-aqueous electrolyte solution according to [1].

[3] The non-aqueous electrolyte solution according to [1], wherein A is a fluorine atom or a substituent containing a fluorine atom in the above formula (1).

[4] The non-described in any of [1] to [3], wherein R ² and R ³ are independently hydrocarbon groups having 1 to 12 carbon atoms in the formula (1). Aqueous electrolyte.

[5] Any of [1] to [4], wherein the aromatic carboxylic acid ester represented by the formula (1) is contained in a non-aqueous electrolytic solution in an amount of 0.001 to 10% by mass. The non-aqueous electrolyte solution described in Crab.

[6] The non-aqueous electrolytic solution according to any one of [1] to [5], wherein the adiponitrile is contained in the non-aqueous electrolytic solution in an amount of 0.001 to 10% by mass.

[7] The non-aqueous electrolysis according to any one of [1] to [6], wherein the non-aqueous electrolytic solution further contains at least one compound selected from a cyclic carbonate having a fluorine atom. liquid.

[8] The description according to any one of [1] to [7], wherein the non-aqueous electrolyte solution further contains at least one compound selected from a cyclic carbonate having a carbon-carbon unsaturated bond. Non-aqueous electrolyte.

[9] A non-aqueous electrolyte battery containing a positive electrode and a negative electrode, and the non-aqueous electrolyte solution according to any one of [1] to [8].

According to the present invention, there is provided a non-aqueous electrolyte solution capable of realizing a non-aqueous electrolyte battery having excellent rate characteristics after a durability test, and a non-aqueous electrolyte battery using the same.

Hereinafter, the present invention will be described in detail. The following description is an example (representative example) of the present invention, and the present invention is not limited thereto. Further, the present invention can be arbitrarily modified and implemented without departing from the gist thereof.

[Non-aqueous electrolyte solution]
The non-aqueous electrolyte solution of the present invention is a non-aqueous electrolyte solution for a non-aqueous electrolyte battery having a positive electrode and a negative electrode capable of storing and releasing metal ions, and the non-aqueous electrolyte solution is described below together with an electrolyte and a non-aqueous solvent. It is characterized by containing an aromatic carboxylic acid ester represented by the formula (1) (hereinafter, may be referred to as "aromatic carboxylic acid ester (1)"), and further containing adiponitrile.

(In the formula (1), R ¹ represents a saturated hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and R ² and R ³ each independently have a fluorine atom or a substituent. It may be a hydrocarbon group having 1 to 12 carbon atoms and may be bonded to each other to form a ring. A may be substituted with a hydrocarbon group having 1 to 12 carbon atoms or a fluorine atom. It is a good alkoxy group having 1 to 12 carbon atoms, a fluorine atom, or a substituent containing a fluorine atom, and m is an integer of 1 to 5. When m is 2 or more, a plurality of A's may be the same as each other. They may be very different, or the two A's may be bonded to each other to form a ring that condenses with a benzene ring having an A.)

In the non-aqueous electrolytic solution of the present invention, the aromatic carboxylic acid ester (1) is bonded to a benzene ring having a specific substituent via a carbon atom having no hydrogen atom on the carbonyl group side of the ester group. The hydrocarbon group bonded to the ether oxygen of the ester group is a saturated hydrocarbon group. Since the aromatic carboxylic acid ester (1) is an aromatic compound having a substituent, it is oxidized on the positive electrode which is in a high potential state during overcharging, and is reduced on the negative electrode when the battery is initially charged, which adversely affects the battery characteristics. However, in the aromatic carboxylic acid ester (1) used in the present invention, the ester group is bonded to the benzene ring via a carbon atom having no hydrogen atom, and the saturated hydrocarbon group is bonded to ether oxygen. Reduction is suppressed. Further, by introducing a specific substituent on the benzene ring, continuous oxidation reaction is less likely to occur, so that the rate characteristics after the durability test of the battery are improved.

Further, by coexisting adiponitrile in the non-aqueous electrolytic solution, the two cyano groups are coordinated with the metal oxide of the positive electrode to suppress the oxidation of the aromatic carboxylic acid ester (1) during the durability test. It is considered that succinonitrile, which has the same dinitrile but has a smaller number of carbon atoms, does not have sufficient coordination with the positive electrode oxide, has a small interaction with the aromatic carboxylic acid ester (1), and has a small effect of suppressing oxidation. .. Therefore, by using the aromatic carboxylic acid ester (1) in combination with adiponitrile, it is possible to improve the capacity and rate characteristics after the high temperature storage durability test without deteriorating the characteristics of the energy device.

[Aromatic Carboxylic Acid Ester (1)]
The non-aqueous electrolyte solution of the present invention contains an aromatic carboxylic acid ester (1). In the aromatic carboxylic acid ester (1) represented by the above formula (1), the cis-trans isomer and the optical isomer cannot be distinguished, and either isomer alone or a mixture thereof can be used. It can also be applied.

In the formula (1), R ¹ is not particularly limited as long as it is a saturated hydrocarbon group having 1 to 12 carbon atoms, and has a cyclic structure regardless of whether it is a linear saturated hydrocarbon group or a branched saturated hydrocarbon group. It may have, or it may have a substituent.
The saturated hydrocarbon group of R ¹ is not particularly limited, but its carbon number is 1 to 12, preferably 8 or less, more preferably 5 or less, still more preferably 2 or less, and most preferably 1.

The saturated hydrocarbon group of R ¹ includes a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, an i-butyl group and a tert-butyl group from the viewpoint of low reactivity. Group, n-pentyl group, isopentyl group, sec-pentyl group, n-pentyl group, 1-methylbutyl group, 2-methylbutyl group, 1,1-dimethylpropyl group, 1,2-dimethylpropyl group, etc. An alkyl group of ~ 5 is preferable, an alkyl group having 1 to 2 carbon atoms of a methyl group or an ethyl group is more preferable from the viewpoint of having less steric damage and high solubility, and a viewpoint of being less reactive with intramolecular oxygen and having low reactivity. From the methyl group is more preferred.

When the saturated hydrocarbon group of R ¹ has a substituent, examples of the substituent include those exemplified as the substituents that R ² and R ³ may have, which will be reduced in the battery. From the viewpoint of not inhibiting the charge / discharge reaction, it is preferable that R ¹ does not have these substituents.

In formula (1), R ² and R ³ are each independently a fluorine atom or a hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and R ² and R ³ are bonded to each other. May form a ring.
When the hydrocarbon groups of R ² and R ³ have a substituent, specific examples of the substituent include a fluorine atom; an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, which may be substituted with a fluorine atom, and the like. A hydrocarbon group such as an aryl group; a cyano group, an isocyanato group, an ether group, a carbonate group, a carbonyl group, a carboxyl group, a sulfonyl group, a phosphantriyl group, a phosphoryl group and the like can be mentioned.

From the viewpoint of solubility in an electrolytic solution, R ² and R ³ are preferably independently substituted with a fluorine atom, an alkyl group optionally substituted with a fluorine atom, and an aryl group optionally substituted with a fluorine atom, respectively. It is preferably an alkyl group that may be substituted with a fluorine atom or a fluorine atom, and more preferably an alkyl group that is not substituted with a fluorine atom.

When R ² and R ³ are hydrocarbon groups, the type thereof is not particularly limited, but the number of carbon atoms is 1 to 12, preferably 10 or less, and more preferably 4 or less.

Specific hydrocarbon groups of R ² and R ³ include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group and tert-butyl group. , An alkyl group having 1 to 4 carbon atoms which may be substituted with a fluorine atom such as a trifluoromethyl group; a vinyl group, a 1-propenyl group, a 2-propenyl group, an isopropenyl group, a 1-butenyl group, a 2-butenyl group. An alkenyl group having 2 to 4 carbon atoms such as a group and a 3-butenyl group; a group having 2 to 4 carbon atoms such as an ethynyl group, a 1-propynyl group, a 2-propynyl group, a 1-butynyl group, a 2-butynyl group and a 3-butenyl group. Alkinyl group of 4; alkyl group having an aromatic group such as benzyl group or phenethyl group as a substituent; phenyl group, tolyl group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, n-butylphenyl group , Se-butylphenyl group, i-butylphenyl group, tert-butylphenyl group, fluorophenyl group, trifluoromethylphenyl group, xsilyl group, methoxyphenyl group, ethoxyphenyl group, trifluoromethoxyphenyl group and other substituents. Examples thereof include a fluorine atom, an alkyl group, a fluoroalkyl group, an alkoxy group, an aryl group which may have one or more of a fluoroalkyl group, and the like.

Of these, substituted with fluorine atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, tert-butyl group and trifluoromethyl group. Alkyl group, phenyl group, trill group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, n-butylphenyl group, sec-butylphenyl group, i- which may be used. An aryl group having 10 or less carbon atoms, which may have a substituent such as a butylphenyl group, a tert-butylphenyl group, a fluorophenyl group, or a trifluoromethylphenyl group, is preferable, and a methyl group, an ethyl group, an n-propyl group, etc. Alkyl groups having 1 to 4 carbon atoms such as groups, i-propyl groups, n-butyl groups, sec-butyl groups, i-butyl groups, and tert-butyl groups are more preferable, and methyl groups or ethyl groups are even more preferable.

When R ² and R ³ are bonded to each other to form a ring, the ring formed by R ² and R ³ and the carbon atom to which R ² and R ³ are bonded is specifically a cyclopropane ring or cyclopentane. Examples thereof include a ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, a cyclooctane ring, and the like, preferably a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, more preferably a cyclopentane ring, a cyclohexane ring, and more preferably. It is a cyclopentane ring.

In the formula (1), A is a substituent on the phenyl group, which is a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a fluorine atom, or a substituent containing a fluorine atom. When A is a substituent containing a fluorine atom, the substituent is preferably a hydrocarbon group, and the hydrocarbon group is a hydrocarbon group having 1 to 12 carbon atoms listed as the hydrocarbon group of A. It is preferable to have.

That is, it is usually used that A is a fluorine atom, a hydrocarbon group having 1 to 12 hydrocarbon groups, an alkoxy group having 1 to 12 carbon atoms, or a hydrocarbon group having 1 to 12 carbon atoms substituted with a fluorine atom. It is preferable from the viewpoint that it is reduced in the battery and does not inhibit the charge / discharge reaction. As the hydrocarbon group of the hydrocarbon group substituted with the fluorine atom, those exemplified as the hydrocarbon group of A exemplified below are preferable.

When the above-mentioned A is a hydrocarbon group, the type thereof is not particularly limited, and it may be linear, have a branch, or have a cyclic structure, but has 1 to 12 carbon atoms. It is preferably 2 or more, more preferably 3 or more, preferably 9 or less, more preferably 6 or less, still more preferably 4 or less.
Examples of the hydrocarbon group of A include an alkyl group, an alkenyl group, an alkynyl group, an aryl group and the like. Of these, an alkyl group and an aryl group are preferable, and an alkyl group is more preferable.

Specific hydrocarbon groups include alkyl such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, tert-butyl group and cyclohexyl group. Group; Alkenyl group such as vinyl group, 1-propenyl group, 2-propenyl group, isopropenyl group, 1-butenyl group, 2-butenyl group, 3-butenyl group; ethynyl group, 1-propynyl group, 2-propynyl group , 1-butynyl group, 2-butynyl group, 3-butynyl group and other alkynyl groups;
Phenyl group, trill group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, n-butylphenyl group, sec-butylphenyl group, i-butylphenyl group, tert-butylphenyl group, cyclohexylphenyl group, An aryl group which may have an alkyl group or an alkoxy group as a substituent such as a xsilyl group, a methoxyphenyl group or an ethoxyphenyl group;
An alkyl group having an aryl group as a substituent such as a benzyl group and a phenethyl group;
Etc.,
Alkyl groups with 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, tert-butyl group; phenyl group, trill Group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, n-butylphenyl group, sec-butylphenyl group, i-butylphenyl group, tert-butylphenyl group, etc. have an alkyl group as a substituent. An aryl group having 10 or less carbon atoms which may be used is preferable.
Alkyl groups having 1 to 4 carbon atoms such as methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group and tert-butyl group are more preferable.
A hydrocarbon group having a quaternary carbon atom bonded to the benzene ring is preferable from the viewpoint of suppressing the reaction in the normal operating range of the battery, and among the alkyl groups having the quaternary carbon atom, the tert-butyl group is particularly preferable. preferable.

The alkoxy group having 1 to 12 carbon atoms which may be substituted with the fluorine atom of A is preferable, and the alkoxy group having 1 to 4 carbon atoms which may be substituted with the fluorine atom is preferable, and the alkoxy group having 1 to 4 carbon atoms is more preferable. It is an alkoxy group of ~ 4. Specific examples of these include methoxy group, ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, monofluoromethoxy group, difluoromethoxy group and trifluoromethoxy. The group etc. can be mentioned.

Examples of the fluorine atom or the substituent containing a fluorine atom of A include a fluorine atom, an alkyl fluoride group, an alkenyl fluoride group, an alkoxy fluoride group, and an aryl fluoride group. Of these, a fluorine atom, an alkyl fluoride group and an aryl fluoride group are preferable, and a fluorine atom is more preferable.
Specific fluorine atoms and hydrocarbon groups containing fluorine atoms include fluorine atoms; monofluoromethyl group, difluoromethyl group, trifluoromethyl group, monofluoroethyl group, difluoroethyl group, trifluoroethyl group, and tetrafluoroethyl group. Fluoroalkyl groups such as groups and pentafluoroethyl groups; Fluoroalkenyl groups such as monofluorovinyl groups, difluorovinyl groups and trifluorovinyl groups; monofluorophenyl groups, 2-fluorotril groups, 3-fluorotril groups, Examples thereof include an aryl fluoride group such as a 4-fluorotril group and a trifluoromethylphenyl group.
Fluorine atom, trifluoromethyl group, monofluorophenyl group, 2-fluorotolyl group, 3-fluorotolyl group, 4-fluorotolyl group, trifluoromethylphenyl group and the like are preferable.
Fluorine atoms are even more preferred.

In the formula (1), m representing the number of A is 1 to 5, preferably 1 to 3 from the viewpoint of solubility, more preferably 1 to 2, and even more preferably 1. When m is 2 or more, a plurality of A's may be the same or different. Further, the two A's may be bonded to each other to form a ring condensed into a benzene ring. In this case, examples of the ring condensed with the benzene ring include a cyclohexane ring, a cyclopentane ring, a 2-methyl-2-phenyl-4,4-dimethylcyclopentane ring, and a benzene ring.

The substitution position of A to be substituted with the benzene ring in the formula (1) is preferably the 2-position, 3-position or 4-position when the carbon atom substituted by the group having an ester group is at the 1-position, and is overcharged. It is preferably in the 4th position from the viewpoint of reactivity at the time.

Specific examples of the aromatic carboxylic acid ester (1) include compounds in the formula (1) in which each substituent is as follows.
R ¹ is a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, an i-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group. A group selected from a group, an n-pentyl group, a 1-methylbutyl group, a 2-methylbutyl group, a 1,1-dimethylpropyl group, and a 1,2-dimethylpropyl group.
R ² and R ³ are independently fluorine atom, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, tert-butyl group, trifluoro. Alkyl group with 1 to 4 carbon atoms such as methyl group, phenyl group, trill group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, n-butylphenyl group, sec-butylphenyl group, i-butyl A phenyl group, a tert-butylphenyl group, a fluorophenyl group, a trifluoromethylphenyl group, or a group selected from those in which R ² and R ³ are bonded to each other to form a cyclobutane ring, a cyclopentane ring, or a cyclohexane ring. can be,
A is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, an i-butyl group, and a tert-butyl group, and phenyl. Group, trill group, ethylphenyl group, n-propylphenyl group, i-propylphenyl group, n-butylphenyl group, sec-butylphenyl group, i-butylphenyl group, tert-butylphenyl group, fluorine atom, trifluoro A group selected from a methyl group, a monofluorophenyl group, a 2-fluorotril group, a 3-fluorotril group, a 4-fluorotril group, a trifluoromethylphenyl group, and a trifluoromethoxyphenyl group.
m is 1 to 3 (when m is 2 to 3, 2 to 3 A's may be the same or different).
A replaces the 2-position, 3-position and 4-position of the benzene ring.

Among these, from the viewpoint of solubility and durability, the aromatic carboxylic acid ester (1) is more preferably a compound in which each substituent in the above formula (1) is as follows.
R ¹ : Methyl group or ethyl group.
R ² , R ³ : Fluorine atom, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, i-butyl group, tert-butyl group, R ² , R ³ Is a group selected from a cyclopentane ring and a cyclohexane ring which are bonded to each other to form a ring.
A: A group selected from a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, a sec-butyl group, an i-butyl group, a tert-butyl group and a fluorine atom, and m = 1. Or 2, and when m = 2, A may be the same or different, and is substituted with the 2-position, 3-position, or 4-position of the benzene ring.

Examples of the aromatic carboxylic acid ester (1) include the following compounds.

The aromatic carboxylic acid ester (1) is most preferably the following compound.

The aromatic carboxylic acid ester (1) may be used alone or in combination of two or more.

The ratio of the aromatic carboxylic acid ester (1) to the non-aqueous electrolyte solution of the present invention is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferable. Is 0.3% by mass or more, and usually 10% by mass or less, preferably 8% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less, and particularly preferably 1.0% by mass or less. .. When the content of the aromatic carboxylic acid ester (1) in the non-aqueous electrolyte solution is within the above range, the effect of the present invention can be easily exhibited and the resistance of the battery can be prevented from increasing.

[Adiponitrile]
The non-aqueous electrolyte solution of the present invention further contains adiponitrile in addition to the aromatic carboxylic acid ester (1).
The ratio of adiponitrile in the non-aqueous electrolyte solution of the present invention is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.3% by mass or more. Further, it is usually 10% by mass or less, preferably 8% by mass or less, more preferably 5% by mass or less, still more preferably 3% by mass or less, and particularly preferably 1.0% by mass or less. When the content of adiponitrile in the non-aqueous electrolyte solution is within the above range, the effect of the present invention can be easily exhibited and the resistance of the battery can be prevented from increasing.

[Cyclic carbonate with fluorine atom]
The non-aqueous electrolyte solution of the present invention contains an aromatic carboxylic acid ester (1) and adiponitrile, as well as a cyclic carbonate having a fluorine atom (hereinafter, may be referred to as "fluorinated cyclic carbonate"). Also, the battery performance can be further improved by containing the fluorinated cyclic carbonate.
The fluorinated cyclic carbonate contained in the non-aqueous electrolytic solution of the present invention is not particularly limited as long as it is a cyclic carbonate having a fluorine atom, and may or may not have an unsaturated bond. ..

Examples of the fluorinated cyclic carbonate include a fluorinated product of a cyclic carbonate having an alkylene group having 2 to 6 carbon atoms and a derivative thereof, and examples thereof include a fluorinated product of ethylene carbonate (hereinafter referred to as “fluorinated ethylene carbonate”). ), And its derivatives. Examples of the derivative of the fluorinated product of ethylene carbonate include a fluorinated product of ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms). Of these, ethylene carbonate having 1 to 8 fluorine atoms and its derivatives are preferable.

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

Among them, at least one selected from the group consisting of monofluoroethylene carbonate, 4,4-difluoroethylene carbonate and 4,5-difluoroethylene carbonate imparts high ionic conductivity and preferably forms an interface protective film. Is more preferable.

As these fluorinated cyclic carbonates, one type may be used alone, or two or more types may be used in combination in any combination and ratio.

Further, as the fluorinated cyclic carbonate, it is also preferable to use a cyclic carbonate having an unsaturated bond and a fluorine atom (hereinafter, may be referred to as “fluorinated unsaturated cyclic carbonate”). The number of fluorine atoms contained in the fluorinated unsaturated cyclic carbonate is not particularly limited as long as it is 1 or more. Among them, the number of fluorine atoms is usually 6 or less, preferably 4 or less, and 1 or 2 is most preferable.

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

Examples of the fluorinated ethylene carbonate derivative substituted with an aromatic ring or a substituent having a carbon-carbon double bond include 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, and 4-fluoro-5. -Vinyl ethylene carbonate, 4-fluoro-5-allylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate , 4,5-Difluoro-4-allylethylene carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylene carbonate , 4,5-Difluoro-4,5-diallylethylene carbonate, 4-fluoro-4-phenylethylene carbonate, 4-fluoro-5-phenylethylene carbonate, 4,4-difluoro-5-phenylethylene carbonate, 4,5 -Difluoro-4-phenylethylene carbonate and the like can be mentioned.

Among them, 4-fluorovinylene carbonate, 4-fluoro-5-methylvinylene carbonate, and 4-fluoro-5- are particularly preferable fluorinated unsaturated cyclic carbonates to be used in combination with the aromatic carboxylic acid ester (1) and adiponitrile. Vinyl vinylene carbonate, 4-allyl-5-fluorovinylene carbonate, 4-fluoro-4-vinylethylene carbonate, 4-fluoro-4-allylethylene carbonate, 4-fluoro-5-vinylethylene carbonate, 4-fluoro-5- Allylethylene carbonate, 4,4-difluoro-4-vinylethylene carbonate, 4,4-difluoro-4-allylethylene carbonate, 4,5-difluoro-4-vinylethylene carbonate, 4,5-difluoro-4-allylethylene Carbonate, 4-fluoro-4,5-divinylethylene carbonate, 4-fluoro-4,5-diallylethylene carbonate, 4,5-difluoro-4,5-divinylethylenecarbonate, 4,5-difluoro-4,5- Diallylethylene carbonate is more preferably used because it forms a stable interface protection film.

The molecular weight of the fluorinated unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effect of the present invention is not significantly impaired. The molecular weight is preferably 50 or more and 250 or less. Within this range, it is easy to secure the solubility of the fluorinated cyclic carbonate in the non-aqueous electrolytic solution, and the effect of the present invention is likely to be exhibited.
The method for producing the fluorinated unsaturated cyclic carbonate is not particularly limited, and a known method can be arbitrarily selected for production. The molecular weight is more preferably 100 or more, and more preferably 200 or less.

As these fluorinated unsaturated cyclic carbonates, one type may be used alone, or two or more types may be used in combination in any combination and ratio.

When the non-aqueous electrolytic solution of the present invention contains a fluorinated cyclic carbonate, the content of the fluorinated cyclic carbonate (total amount in the case of two or more kinds) in the non-aqueous electrolytic solution is 0.001% by mass or more, preferably 0.001% by mass or more. 0.01% by mass or more, more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, particularly preferably 0.5% by mass or more, and 10% by mass or less, preferably 5 by mass. It is mass% or less, more preferably 4% by mass or less, still more preferably 3% by mass or less, and particularly preferably 2% by mass or less.

The fluorinated cyclic carbonate can also be used as a non-aqueous solvent, and in that case, the content in the non-aqueous electrolyte solution is preferably 1% by volume or more, more preferably 5% by volume in 100% by volume of the non-aqueous solvent. The above is more preferably 10% by volume or more, preferably 50% by volume or less, more preferably 35% by volume or less, still more preferably 25% by volume or less.
Within this range, the energy device tends to exhibit a sufficient effect of improving the cycle characteristics, and it is easy to avoid a situation in which the high temperature storage characteristics deteriorate, the amount of gas generated increases, and the discharge capacity retention rate decreases. ..

[Cyclic carbonate with carbon-carbon unsaturated bond]
The non-aqueous electrolyte solution of the present invention contains a cyclic carbonate having a carbon-carbon unsaturated bond (hereinafter, may be abbreviated as "unsaturated cyclic carbonate") in addition to the aromatic carboxylic acid ester (1) and adiponitrile. It may be one, and the battery performance can be further improved by containing the unsaturated cyclic carbonate.

The unsaturated cyclic carbonate contained in the non-aqueous electrolyte solution of the present invention is not particularly limited as long as it is a cyclic carbonate having a carbon-carbon double bond or a carbon-carbon triple bond, and any unsaturated cyclic carbonate may be used. be able to. The cyclic carbonate having an aromatic ring is also included in the unsaturated cyclic carbonate. Examples of unsaturated cyclic carbonates include vinylene carbonates, ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon double bond or a carbon-carbon triple bond, phenyl carbonates, vinyl carbonates, allyl carbonates, and the like. Examples thereof include catechol carbonates.

Examples of vinylene carbonates include vinylene carbonate, methylvinylene carbonate, 4,5-dimethylvinylene carbonate, phenylvinylene carbonate, 4,5-diphenylvinylene carbonate, vinylvinylene carbonate, 4,5-vinylvinylene carbonate, allylvinylene carbonate, 4 , 5-Diallyl vinylene carbonate and the like.

Specific examples of ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon double bond or a carbon-carbon triple bond include vinyl ethylene carbonate, 4,5-divinylethylene carbonate, and 4-methyl-5. Vinyl ethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5-dietinylethylene carbonate, 4-methyl-5-ethynylethylene carbonate, 4-vinyl-5-ethynylethylene carbonate, 4-allyl -5-Etinylethylene carbonate, phenylethylenecarbonate, 4,5-diphenylethylenecarbonate, 4-phenyl-5-vinylethylenecarbonate, 4-allyl-5-phenylethylenecarbonate, allylethylenecarbonate, 4,5-diallylethylenecarbonate , 4-Methyl-5-allylethylene carbonate and the like.

Among them, vinylene carbonate, methylvinylene carbonate, 4,5-dimethylvinylene carbonate, vinylvinylene carbonate, and 4,5-vinyl are particularly preferable unsaturated cyclic carbonates for use in combination with the aromatic carboxylic acid ester (1) and adiponitrile. Vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate, vinyl ethylene carbonate, 4,5-divinylethylene carbonate, 4-methyl-5-vinylethylene carbonate, allylethylene carbonate, 4,5-diallylethylene carbonate, 4 -Methyl-5-allylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5-diethynylethylene carbonate, 4-methyl-5-ethynylethylene carbonate, 4-vinyl-5-ethynylethylene Examples include carbonate. Further, vinylene carbonate, vinylethylene carbonate and ethynylethylene carbonate are particularly preferable because they form a more stable interface protective film.

The molecular weight of the unsaturated cyclic carbonate is not particularly limited and is arbitrary as long as the effect of the present invention is not significantly impaired. The molecular weight is preferably 86 or more and 250 or less. Within this range, it is easy to secure the solubility of the unsaturated cyclic carbonate in the non-aqueous electrolytic solution, and the effect of the present invention is likely to be sufficiently exhibited. The molecular weight of the unsaturated cyclic carbonate is more preferably 86 or more and 150 or less. The method for producing the unsaturated cyclic carbonate is not particularly limited, and a known method can be arbitrarily selected for production.

The unsaturated cyclic carbonate may be used alone or in combination of two or more in any combination and ratio.

When the non-aqueous electrolyte solution of the present invention contains an unsaturated cyclic carbonate, the content thereof is not particularly limited and is arbitrary as long as the effects of the present invention are not significantly impaired. The content of the unsaturated cyclic carbonate is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, still more preferably 0.1% by mass or more in 100% by mass of the non-aqueous electrolyte solution. Further, it is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less. Within this range, the non-aqueous electrolyte battery tends to exhibit a sufficient effect of improving the cycle characteristics, the high temperature storage characteristics deteriorate, the amount of gas generated increases, and the discharge capacity retention rate decreases. Easy to avoid.

[Non-aqueous solvent]
Like a general non-aqueous electrolyte solution, the non-aqueous electrolyte solution of the present invention usually contains a non-aqueous solvent that dissolves an electrolyte described later as its main component. The non-aqueous solvent used here is not particularly limited, and known organic solvents can be used. The organic solvent preferably includes, but is not limited to, at least one selected from saturated cyclic carbonates, chain carbonates, chain carboxylic acid esters, cyclic carboxylic acid esters, ether compounds, and sulfone compounds. .. These can be used alone or in combination of two or more.

<Saturated cyclic carbonate>
Examples of the saturated cyclic carbonate include those having an alkylene group having 2 to 4 carbon atoms. Specifically, examples of the saturated cyclic carbonate having 2 to 4 carbon atoms include ethylene carbonate, propylene carbonate, butylene carbonate and the like. Of these, ethylene carbonate and propylene carbonate are preferable from the viewpoint of improving battery characteristics due to the improvement in the degree of lithium ion dissociation. As the saturated cyclic carbonate, one type may be used alone, or two or more types may be used in combination in any combination and ratio.

When the non-aqueous electrolyte solution of the present invention contains a saturated cyclic carbonate as a non-aqueous solvent, the content thereof is not particularly limited and is arbitrary as long as the effect of the present invention is not significantly impaired. The lower limit of the content of is usually 3% by volume or more, preferably 5% by volume or more in 100% by volume of the non-aqueous solvent. By setting this range, it is easy to avoid the decrease in electrical conductivity due to the decrease in the dielectric constant of the non-aqueous electrolyte solution, and to make the large current discharge characteristics of the power storage device, the stability with respect to the negative electrode, and the cycle characteristics within a good range. .. The upper limit is usually 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less. By setting this range, the viscosity of the non-aqueous electrolyte solution can be set to an appropriate range, the decrease in ionic conductivity can be suppressed, the input / output characteristics of the power storage device can be further improved, and the durability such as cycle characteristics and storage characteristics can be improved. It is preferable because it can be further improved.

<Chain carbonate>
The chain carbonate is preferably one having 3 to 7 carbon atoms. Specifically, examples of the chain carbonate having 3 to 7 carbon atoms include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propylisopropylcarbonate, ethylmethylcarbonate, and methyl-n-propylcarbonate. Examples thereof include n-butyl methyl carbonate, isobutyl methyl carbonate, t-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butyl ethyl carbonate, isobutyl ethyl carbonate, t-butyl ethyl carbonate and the like. Among these, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propylisopropyl carbonate, ethylmethylcarbonate and methyl-n-propylcarbonate are preferable, and dimethylcarbonate, diethylcarbonate and ethylmethylcarbonate are particularly preferable. preferable.

Further, chain carbonates having a fluorine atom (hereinafter, may be abbreviated as "fluorinated chain carbonate") can also be preferably used. The number of fluorine atoms contained in the fluorinated chain carbonate is not particularly limited as long as it is 1 or more, but is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon atom or different carbon atoms. Examples of the fluorinated chain carbonate include a fluorinated dimethyl carbonate derivative, a fluorinated ethylmethyl carbonate derivative, and a fluorinated diethyl carbonate derivative.

As the chain carbonate, one type may be used alone, or two or more types may be used in combination in any combination and ratio.

When the non-aqueous electrolyte solution of the present invention contains a chain carbonate as a non-aqueous solvent, the content thereof is not particularly limited, but is usually 15% by volume or more, preferably 20% by volume or more in 100% by volume of the non-aqueous solvent. , More preferably 25% by volume or more. Further, it is usually 90% by volume or less, preferably 85% by volume or less, and more preferably 80% by volume or less. By setting the content of the chain carbonate in the above range, the viscosity of the non-aqueous electrolyte solution is set in an appropriate range, the decrease in ionic conductivity is suppressed, and the input / output characteristics and charge / discharge rate characteristics of the power storage device are good. It becomes easier to make a range. In addition, the decrease in electrical conductivity due to the decrease in the dielectric constant of the non-aqueous electrolyte solution is avoided, and the input / output characteristics and charge / discharge rate characteristics of the power storage device can be easily set in a good range.

<Chainous carboxylic acid ester>
Examples of the chain carboxylic acid ester include those having a total carbon number of 3 to 7 in the structural formula. Specifically, methyl acetate, ethyl acetate, -n-propyl acetate, isopropyl acetate, -n-butyl acetate, isobutyl acetate, -t-butyl acetate, methyl propionate, ethyl propionate, -n-propyl propionate, Isopropyl propionate, -n-butyl propionate, isobutyl propionate, -t-butyl propionate, methyl butyrate, ethyl butyrate, -n-propyl butyrate, isopropyl butyrate, methyl isobutyrate, ethyl isobutyrate, -n-isobutyrate Examples thereof include propyl and isopropyl isobutyrate. Among these, methyl acetate, ethyl acetate, -n-propyl acetate, -n-butyl acetate, methyl propionate, ethyl propionate, -n-propyl propionate, isopropyl propionate, methyl butyrate, ethyl butyrate and the like have viscosities. It is preferable from the viewpoint of improving the ionic conductivity due to the decrease and suppressing the battery swelling during the durability test such as cycle and storage.

<Cyclic carboxylic acid ester>
Examples of the cyclic carboxylic acid ester include those having a total carbon atom number of 3 to 12 in the structural formula. Specific examples thereof include gamma-butyrolactone, gamma delta-valerolactone, gamma caprolactone, and epsilon caprolactone. Among these, gamma-butyrolactone is particularly preferable from the viewpoint of improving battery characteristics derived from the improvement of the degree of lithium ion dissociation.

<Ether compounds>
As the ether compound, a chain ether having 3 to 10 carbon atoms and a cyclic ether having 3 to 6 carbon atoms are preferable.

Examples of the chain ether having 3 to 10 carbon atoms include diethyl ether, di (2-fluoroethyl) ether, di (2,2-difluoroethyl) ether, di (2,2,2-trifluoroethyl) ether, and ethyl. (2-Fluoroethyl) ether, ethyl (2,2,2-trifluoroethyl) ether, ethyl (1,1,2,2-tetrafluoroethyl) ether, (2-fluoroethyl) (2,2,2) -Trifluoroethyl) ether, (2-fluoroethyl) (1,1,2,2-tetrafluoroethyl) ether, (2,2,2-trifluoroethyl) (1,1,2,2-tetrafluoro) Ethyl) ether, ethyl-n-propyl ether, ethyl (3-fluoro-n-propyl) ether, ethyl (3,3,3-trifluoro-n-propyl) ether, ethyl (2,2,3,3- Tetrafluoro-n-propyl) ether, ethyl (2,2,3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n-propyl ether, (2-fluoroethyl) (3-fluoro) -N-propyl) ether, (2-fluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2-fluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ) Ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, 2,2,2-trifluoroethyl-n-propyl ether, (2,2,2) -Trifluoroethyl) (3-fluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (2,2,2- Trifluoroethyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,2-trifluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ) Ether, 1,1,2,2-tetrafluoroethyl-n-propyl ether, (1,1,2,2-tetrafluoroethyl) (3-fluoro-n-propyl) ether, (1,1,2) , 2-Tetrafluoroethyl) (3,3,3-trifluoro-n-propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,3-tetrafluoro-n-) Propyl) ether, (1,1,2,2-tetrafluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-propyl Ether, (n-propyl) (3-fluoro-n-propyl) ether, (n-propyl) (3,3,3-trifluoro-n-propyl) ether, (n-propyl) (2,2,3) , 3-Tetrafluoro-n-propyl) ether, (n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3-fluoro-n-propyl) ether, ( 3-Fluoro-n-propyl) (3,3,3-trifluoro-n-propyl) ether, (3-fluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether , (3-Fluoro-n-propyl) (2,2,3,3,3-pentafluoro-n-propyl) ether, di (3,3,3-trifluoro-n-propyl) ether, (3, 3,3-Trifluoro-n-propyl) (2,2,3,3-tetrafluoro-n-propyl) ether, (3,3,3-trifluoro-n-propyl) (2,2,3) 3,3-Pentafluoro-n-propyl) ether, di (2,2,3,3-tetrafluoro-n-propyl) ether, (2,2,3,3-tetrafluoro-n-propyl) (2) , 2,3,3,3-pentafluoro-n-propyl) ether, di (2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, methoxyethoxy Methoxy, methoxy (2-fluoroethoxy) methane, methoxy (2,2,2-trifluoroethoxy) methanemethoxy (1,1,2,2-tetrafluoroethoxy) methane, diethoxymethane, ethoxy (2-fluoroethoxy) ) Methoxy, ethoxy (2,2,2-trifluoroethoxy) methane, ethoxy (1,1,2,2-tetrafluoroethoxy) methane, di (2-fluoroethoxy) methane, (2-fluoroethoxy) (2) , 2,2-Trifluoroethoxy) methane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methanedi (2,2,2-trifluoroethoxy) methane, (2,2,2) -Trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) methane, di (1,1,2,2-tetrafluoroethoxy) methane, dimethoxyethane, methoxyethoxyethane, methoxy (2-fluoroethoxy) Ether, methoxy (2,2,2-trifluoroethoxy) ethane, methoxy (1,1,2,2-tetrafluoroetho) Kishi) ethane, diethoxyethane, ethoxy (2-fluoroethoxy) ethane, ethoxy (2,2,2-trifluoroethoxy) ethane, ethoxy (1,1,2,2-tetrafluoroethoxy) ethane, di (2) -Fluoroethoxy) ethane, (2-fluoroethoxy) (2,2,2-trifluoroethoxy) ethane, (2-fluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (2,2) 2,2-Trifluoroethoxy) ethane, (2,2,2-trifluoroethoxy) (1,1,2,2-tetrafluoroethoxy) ethane, di (1,1,2,2-tetrafluoroethoxy) Examples thereof include ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether.

Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, and 1 , 4-Dioxane and the like, and fluorides thereof.

Among these, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have high solvation ability to lithium ions and are lithium ion dissociative. It is preferable in terms of improving. Particularly preferred are dimethoxymethane, diethoxymethane, and ethoxymethoxymethane because they have low viscosity and give high ionic conductivity.

<Sulfone compound>
As the sulfone compound, a cyclic sulfone having 3 to 6 carbon atoms and a chain sulfone having 2 to 6 carbon atoms are preferable. The number of sulfonyl groups in one molecule is preferably 1 or 2.

Examples of the cyclic sulfone include trimethylene sulfones, tetramethylene sulfones and hexamethylene sulfones which are monosulfone compounds; and trimethylene disulfones, tetramethylene disulfones and hexamethylene disulfones which are disulfone compounds. Among these, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable, from the viewpoint of dielectric constant and viscosity.

As the sulfolanes, sulfolanes and / or sulfolane derivatives (hereinafter, sulfolanes may be abbreviated as "sulfolanes") are preferable. As the sulfolane derivative, one in which one or more of the hydrogen atoms bonded on the carbon atom constituting the sulfolane ring is substituted with a fluorine atom or an alkyl group is preferable.

Among these, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorolane Sulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2-fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-fluoro-3 -Methyl sulfolane, 4-fluoro-2-methyl sulfolane, 5-fluoro-3-methyl sulfolane, 5-fluoro-2-methyl sulfolane, 2-fluoromethyl sulfolane, 3-fluoromethyl sulfolane, 2-difluoromethyl sulfolane, 3 -Difluoromethyl sulfolane, 2-trifluoromethyl sulfolane, 3-trifluoromethyl sulfolane, 2-fluoro-3- (trifluoromethyl) sulfolane, 3-fluoro-3- (trifluoromethyl) sulfolane, 4-fluoro-3 -(Trifluoromethyl) sulfolane, 5-fluoro-3- (trifluoromethyl) sulfolane and the like are preferable in that they have high ionic conductivity and high input / output.

Examples of the chain sulfone include dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, n-propyl ethyl sulfone, di-n-propyl sulfone, isopropyl methyl sulfone, isopropyl ethyl sulfone, diisopropyl sulfone, and n-. Butylmethyl sulfone, n-butylethyl sulfone, t-butylmethyl sulfone, t-butylethyl sulfone, monofluoromethylmethyl sulfone, difluoromethylmethyl sulfone, trifluoromethylmethyl sulfone, monofluoroethylmethyl sulfone, difluoroethylmethyl sulfone, Trifluoroethyl Methyl Sulfone, Pentafluoroethyl Methyl Sulfone, Ethyl Monofluoro Methyl Sulfone, Ethyl Difluoro Methyl Sulfone, Ethyl Trifluoro Methyl Sulfone, Perfluoro Ethyl Methyl Sulfone, Ethyl Trifluoro Ethyl Sulfone, Ethyl Pentafluoro Ethyl Sulfone, Di (Tri) Fluoroethyl) sulfone, perfluorodiethyl sulfone, fluoromethyl-n-propyl sulfone, difluoromethyl-n-propyl sulfone, trifluoromethyl-n-propyl sulfone, fluoromethyl isopropyl sulfone, difluoromethyl isopropyl sulfone, trifluoromethyl isopropyl sulfone , Trifluoroethyl-n-propyl sulfone, trifluoroethyl isopropyl sulfone, pentafluoroethyl-n-propyl sulfone, pentafluoroethyl isopropyl sulfone, trifluoroethyl-n-butyl sulfone, trifluoroethyl-t-butyl sulfone, penta Fluoroethyl-n-butyl sulfone, pentafluoroethyl-t-butyl sulfone and the like can be mentioned.

Among these, dimethyl sulfone, ethyl methyl sulfone, diethyl sulfone, n-propyl methyl sulfone, isopropyl methyl sulfone, n-butyl methyl sulfone, t-butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl. Methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone, ethyl trifluoromethyl sulfone, ethyl trifluoroethyl sulfone, ethyl Pentafluoroethyl sulfone, trifluoromethyl-n-propyl sulfone, trifluoromethyl isopropyl sulfone, trifluoroethyl-n-butyl sulfone, trifluoroethyl-t-butyl sulfone, trifluoromethyl-n-butyl sulfone, trifluoromethyl -T-Butyl sulfone or the like is preferable because it has high ionic conductivity and high input / output.

[Electrolytes]
The non-aqueous electrolyte solution of the present invention usually contains an electrolyte. In particular, when the non-aqueous electrolyte solution of the present invention is a lithium ion secondary battery, it usually contains a lithium salt. The following lithium salt (A) is used to increase the ionic conductivity of the non-aqueous electrolyte solution, and a lithium salt other than the lithium salt (A) is used to further enhance the desired performance of the non-aqueous electrolyte solution of the present invention. (B) can also be used. When the non-aqueous electrolyte solution of the present invention is used in a sodium ion secondary battery, it is preferable to use a sodium salt in which lithium ions are replaced with sodium ions for each of the lithium salts exemplified below.

Examples of the lithium salt (A) that can be used in the non-aqueous electrolyte solution of the present invention include LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAsF ₆ , and LiTaF ₆ . Among these, it is preferable to include at least one of LiBF ₄ and LiPF ₆ . Further, the lithium salt (A) may be used alone or in combination of two or more.

When the non-aqueous electrolyte solution of the present invention contains the lithium salt (A), the content thereof is preferably 0.5 mol / L or more, more preferably 0.6 mol / L or more with respect to the non-aqueous solvent. It is more preferably 0.7 mol / L or more, while it is preferably 3 mol / L or less, more preferably 2 mol / L or less, still more preferably 1.8 mol / L or less. When the content of the lithium salt (A) is within the above range, the ionic conductivity can be appropriately increased.

The lithium salts (B) that can be used in the non-aqueous electrolyte solution of the present invention include LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, and Li (C ₂ F ₅ ). SO ₂ ) ₂ N, Li (CF ₃ ) SO ₂ ) ₃ C, LiBF ₃ (C ₂ F ₅ ), LiB (C ₂ O ₄ ) ₂ , LiB (C ₆ F ₅ ) ₄ , LiPF ₃ (C ₂ F) ₅ ) ₃ , LiPO ₂ F ₂ , LiFSO ₃ and the like can be mentioned. These may be used alone or in combination of two or more.

When the non-aqueous electrolyte solution of the present invention contains a lithium salt (B), the content thereof is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, based on the non-aqueous solvent. On the other hand, it is preferably 20% by mass or less, more preferably 15% by mass or less, further preferably 10% by mass or less, and particularly preferably 5% by mass or less. When the content of the lithium salt (B) is within the above range, the ionic conductivity can be appropriately increased.

The method for measuring the content of the lithium salt mentioned above is not particularly limited, and a known method can be arbitrarily used. Examples of such a method include ion chromatography, F magnetic resonance spectroscopy and the like.

[Other additives]
In addition to the various compounds listed above, the non-aqueous electrolyte solution of the present invention has malononitrile, succinonitrile, glutaronitrile, pimeronitrile, suberonitrile, azelanitrile, sevaconitrile, undecandinitrile, and dodecandinitrile as storage property improving agents. Compounds having a cyano group other than adiponitrile such as; 1,3-bis (isocyanatomethyl) cyclohexane, 1,4-bis (isocyanatomethyl) cyclohexane, 1,3-phenylenedi isocyanate, 1,4 as negative electrode protective agents. -Diisocyanato compounds such as phenylenedi isocyanate, 1,2-bis (isocyanatomethyl) benzene, 1,3-bis (isosianatomethyl) benzene, 1,4-bis (isocyanatomethyl) benzene; as a durability improver. Acrylic acid anhydride, 2-methylacrylic acid anhydride, 3-methylacrylic acid anhydride, benzoic acid anhydride, 2-methylbenzoic acid anhydride, 4-methylbenzoic acid anhydride, 4-tert-butyl benzoic acid anhydride Auxiliary agents such as carboxylic acid anhydride compounds such as 4-fluorobenzoic acid anhydride, 2,3,4,5,6-pentafluorobenzoic acid anhydride, methoxygic acid anhydride and ethoxygic acid anhydride; overcharge. As the inhibitor, various additives such as cyclohexylbenzene, t-butylbenzene, t-amylbenzene, biphenyl, alkylbiphenyl, terphenyl, partially hydride of terphenyl, diphenyl ether, dibenzofuran and the like significantly impair the effect of the present invention. It can be blended in a range that does not exist. These compounds may be used in combination as appropriate.

[Non-aqueous electrolyte battery]
The non-aqueous electrolyte solution, the positive electrode and the negative electrode of the present invention can be used as a non-aqueous electrolyte solution (hereinafter, may be referred to as “the non-aqueous electrolyte battery of the present invention”). Examples of the non-aqueous electrolyte battery include a lithium ion secondary battery, a sodium ion secondary battery, and the like, but a lithium ion secondary battery is preferable. A lithium ion secondary battery usually has a non-aqueous electrolyte solution of the present invention, a current collector, and a positive electrode having a positive electrode active material layer provided on the current collector and capable of storing and releasing lithium ions. It has a negative electrode active material layer provided on the electric body and the current collector, and includes a negative electrode capable of storing and releasing lithium ions.

[Positive electrode]
The positive electrode used in the non-aqueous electrolyte battery of the present invention usually contains a composite oxide, a polyanionic compound, a fluoride and the like. The positive electrode usually has a positive electrode active material layer on the current collector, and the positive electrode active material layer contains a positive electrode active material. Hereinafter, the positive electrode active material will be described.

Examples of the composite oxide include those represented by the following formula (2).
Li _x M _1-y N _y O ₂ (2)

In the formula (2), 0 <x <1.2 and 0 <y <1.

M in the formula (2) is a transition metal, preferably Mn, Fe, Co, and Ni. As M in the formula (2), only one kind may be contained in the composite oxide, or a plurality of different kinds may be contained.

N in the formula (2) is at least one selected from V, Fe, Cu, Nb, Mo, Ta, W, Zn, Ti, Zr, Al, B, Mg, Li, Na and K. Among these, from the viewpoint of improving output, at least one selected from V, Fe, Cu, Nb, Mo, Ta and W is preferable, and among these, at least one selected from Nb, Mo, Ta and W is more preferable. On the other hand, from the viewpoint of the capacity retention rate after the durability test, at least one selected from Zn, Ti, Zr, Al, B, Mg, Li, Na and K is preferable, and among these, Zr, Al, Mg and Li are selected. At least one is more preferred.

Preferred composite oxides _are , for example, Na _2/3 Fe _1/2 Mn _1/2 O _{2 ,} Na _{2/3 Ni 1/2 Mn 1/2} O _{2 , Na 2/3 Ni 1/3 Mn} . _2/3 O ₂ , Na _4/5 Ni _1/3 Mn _2/3 O ₂ , _{NaCoO 2 , NaCrO 2 , NaNi 1/3 Co 1/3 Mn 1/3} O _{2 , NaNi 1/3 Fe 1/3 Mn 1/3 O 2 and the} like can be mentioned.

Examples of the polyanionic compound include those represented by the following formula (3).
Na _{x` M'y`} (QO ₄ ) _z (3)

In the formula (3), 1 <x` <2, 1 <y` <3, 1 <z <3.

M'in the formula (3) is a transition metal, preferably Mn, Fe, Co, and Ni. M'in the formula (3) may contain only one kind of the polyanion compound, or may contain a plurality of different kinds.

Q in the formula (3) is at least one selected from P, As, Sb, Bi, S, Se, Te, Po, Si, Ge, Sn and Pb. Among these, at least one selected from P, S, and Si is preferable, and at least one selected from P and S is more preferable from the viewpoint of the stability of the compound.

Preferred polyanionic compounds include, for example, LiFePO ₄ , Li ₂ Fe ₃ (PO ₄ ) ₃ , Li ₂ Fe ₂ (SO ₄ ) ₃ , Li ₂ Fe ₂ (SiO ₄ ) ₃ , LiMnPO ₄ , LiMnFe ₂ (PO). ₄ ) ₃ , Li ₂ Mn ₂ (SO ₄ ) ₃ , Li ₂ Mn ₂ (SiO ₄ ) ₃ , and the like.

Examples of the fluoride include _LiM''F3 and _{Li2M''PO4F (} where M'' is a transition metal, preferably Mn, Fe, Co, Ni, and one kind. (Only may be contained, or a plurality of different species may be contained), and more specifically, LiFeF ₃ , Li ₂ FePO ₄ F, LiFMnF ₃ , Li ₂ MnPO ₄ F, LiFNiF ₃ , Examples thereof include Li ₂ NiPO ₄ F and the like.

Among the above-mentioned positive electrodes, those containing a composite oxide, a polyaniline compound and a fluoride are preferable, but other positive electrode active materials may be contained as long as the effects of the present invention are not impaired. The other positive electrode active material is not particularly limited as long as it does not correspond to any of the composite oxide, the polyanionic compound and the fluoride and can occlude and release s-block metal ions electrochemically. However, for example, a substance containing an alkali metal and at least one transition metal is preferable. Specific examples include a lithium-containing transition metal composite oxide, a lithium-containing transition metal phosphoric acid compound, and a lithium-containing transition metal silicate compound. For example, Na ₂ FeP ₂ O ₇ and Na ₄ Fe ₃ (PO ₄ ) ₂ (P ₂ O ₇ ) and the like can be mentioned. The above-mentioned other positive electrode active materials may be used alone or in combination of two or more.

[Negative electrode]
The negative electrode usually has a negative electrode active material layer on the current collector, and the negative electrode active material layer contains a negative electrode active material. Hereinafter, the negative electrode active material will be described.

The negative electrode active material is not particularly limited as long as it can electrochemically occlude and release s-block metal ions such as lithium ion, lithium ion, potassium ion and magnesium ion. Specific examples thereof include carbonaceous materials, metal alloy materials, s-block metal-containing metal composite oxide materials, and the like. These may be used alone or in combination of two or more.

Examples of the carbonaceous material used as the negative electrode active material include natural graphite, non-graphitized carbon, artificial carbonaceous material, etc., but there is no particular limitation, and usually, a pore structure is available in which lithium ions can be inserted and removed. do it. Specifically, the porous single-phase material described in International Publication No. 2014/188722 is preferable from the viewpoint of high capacity.

[Separator]
A separator is usually interposed between the positive electrode and the negative electrode to prevent a short circuit. In this case, the non-aqueous electrolytic solution of the present invention is usually used by impregnating this separator.

The material and shape of the separator are not particularly limited, and any known separator can be used as long as the effect of the present invention is not significantly impaired. Among these, resins, glass fibers, inorganic substances, etc., which are made of a material stable to the non-aqueous electrolyte solution of the present invention, are used, and porous sheets or non-woven fabrics having excellent liquid retention properties are used. It is preferable to use it.

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

The thickness of the separator is arbitrary, but is usually 1 μm or more, preferably 5 μm or more, more preferably 10 μm or more, and usually 50 μm or less, preferably 40 μm or less, and more preferably 30 μm or less. If the separator is too thin than the above range, the insulating property and the mechanical strength may be deteriorated. Further, if it is too thick than the above range, not only the battery performance such as rate characteristics may deteriorate, but also the energy density of the entire power storage device may decrease.

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

The average pore size of the separator is also arbitrary, but is usually 0.5 μm or less, preferably 0.2 μm or less, and usually 0.05 μm or more. If the average hole diameter exceeds the above range, a short circuit is likely to occur. Further, if it is below the above range, the film resistance may increase and the rate characteristics may deteriorate.

On the other hand, as the inorganic material, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used, and have a particle shape or a fiber shape. Things are used.

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

[Conductive material]
The positive electrode and the negative electrode described above may contain a conductive material in order to improve conductivity. As the conductive material, a known conductive material can be arbitrarily used. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite (graphite); carbon black such as acetylene black; carbonaceous materials such as amorphous carbon such as needle coke. It should be noted that one of these may be used alone, or two or more of them may be used in any combination and ratio.

The conductive material is usually 0.01 part by mass or more, preferably 0.1 part by mass or more, more preferably 1 part by mass or more, and usually 50 parts by mass or less, preferably 50 parts by mass or more, based on 100 parts by mass of the positive electrode material or the negative electrode material. Is used so as to contain 30 parts by mass or less, more preferably 15 parts by mass or less. If the content of the conductive material is lower than the above range, the conductivity may be insufficient. If it exceeds the above range, the battery capacity may decrease.

[Binder]
The positive electrode and the negative electrode described above may contain a binder in order to improve the binding property. The binder is not particularly limited as long as it is a material that is stable to a non-aqueous electrolyte solution and a solvent used in manufacturing the electrode.

In the case of the coating method, the binder may be a material that is dissolved or dispersed in the liquid medium described later used in the manufacture of the electrode, and specific examples thereof include polyethylene, polypropylene, polyethylene terephthalate, polymethylmethacrylate, and aroma. Resin-based polymers such as group polyamide, cellulose, nitrocellulose; rubber-like polymers such as SBR (styrene / butadiene rubber), NBR (acrylonitrile / butadiene rubber), fluoroatomic rubber, isoprene rubber, butadiene rubber, ethylene / propylene rubber, etc. Styrene / butadiene / styrene block copolymer or its hydrogen additive, EPDM (ethylene / propylene / diene ternary copolymer), styrene / ethylene / butadiene / ethylene copolymer, styrene / isoprene / styrene block copolymer Or a thermoplastic elastomer-like polymer such as a hydrogenated product thereof; a soft resin-like height such as syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene / vinyl acetate copolymer, propylene / α-olefin copolymer, etc. Moleculars: Fluorine atomic polymers such as polyfluorovinylidene (PVdF), polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene / ethylene copolymer; ionic conductivity of alkali metal ions (particularly lithium ions) Examples thereof include polymer compositions having. In addition, these substances may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

The ratio of the binder is usually 0.1 part by mass or more, preferably 1 part by mass or more, more preferably 3 parts by mass or more, and usually 50 parts by mass with respect to 100 parts by mass of the positive electrode material or the negative electrode material. It is less than or equal to, preferably 30 parts by mass or less, more preferably 10 parts by mass or less, and further preferably 8 parts by mass or less. When the ratio of the binder is within the above range, the binding property of the electrode can be sufficiently maintained, the mechanical strength of the electrode is maintained, and it is preferable from the viewpoint of cycle characteristics, battery capacity and conductivity.

[Liquid medium]
When forming a positive electrode and a negative electrode by the coating method, the liquid medium for forming the slurry is to dissolve or disperse an active material, a conductive material, a binder, and a thickener used as necessary. The type of the solvent is not particularly limited as long as it can be used, and either an aqueous solvent or an organic solvent may be used.

Examples of the aqueous medium include water, a mixed medium of alcohol and water, and the like. Examples of organic media include aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; ketones such as acetone, methyl ethyl ketone and cyclohexanone. Classes; esters such as methyl acetate and methyl acrylate; amines such as diethylenetriamine, N, N-dimethylaminopropylamine; ethers such as diethyl ether and tetrahydrofuran (THF); N-methylpyrrolidone (NMP), dimethylformamide. , Amides such as dimethylacetamide; aprotonic polar solvents such as hexamethylphosphalamide and dimethylsulfoxide can be mentioned. In addition, these may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

[Thickener]
When forming a positive electrode and a negative electrode by the coating method and using an aqueous medium as a liquid medium for forming a slurry, it is recommended to use a thickener and a latex such as styrene-butadiene rubber (SBR) to form a slurry. preferable. Thickeners are typically used to adjust the viscosity of the slurry.

The thickener is not limited as long as the effect of the present invention is not significantly limited, but specifically, carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein and salts thereof. And so on. These may be used alone or in combination of two or more in any combination and ratio.

When these thickeners are used, the amount used is usually 0.1 part by mass or more, preferably 0.5 part by mass or more, and more preferably 0.6 parts by mass with respect to 100 parts by mass of the positive electrode material or the negative electrode material. It is preferably 5 parts by mass or less, usually 5 parts by mass or less, preferably 3 parts by mass or less, and more preferably 2 parts by mass or less. If it is below the above range, the coatability may be significantly reduced, and if it is above the above range, the ratio of the active material to the active material layer is reduced, which causes a problem of a decrease in battery capacity and an increase in resistance between the active materials. May be done.

[Current collector]
The material of the current collector is not particularly limited, and any known material can be used. Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, tantalum, and copper; and carbonaceous materials such as carbon cloth and carbon paper. Among these, metal materials, especially aluminum, are preferable.

Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punch metal, foamed metal, etc. in the case of metal material, and carbon plate in the case of carbonaceous material. Examples include a carbon thin film and a carbon column. Of these, a metal thin film is preferable. The thin film may be formed in a mesh shape as appropriate.

The thickness of the current collector is arbitrary, but is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and usually 1 mm or less, preferably 100 μm or less, and more preferably 50 μm or less. When the thickness of the current collector is within the above range, the strength required for the current collector is maintained, and it is preferable from the viewpoint of handleability.

[Battery design]
<Electrode group>
The electrode group has a laminated structure in which the above-mentioned positive electrode plate and the negative electrode plate are interposed via the above-mentioned separator, and a structure in which the above-mentioned positive electrode plate and the negative electrode plate are spirally wound through the above-mentioned separator. Either may be used. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as the electrode group occupancy rate) is usually 40% or more, preferably 50% or more, and usually 90% or less, 80% or less. preferable. When the electrode group occupancy rate is lower than the above range, the battery capacity becomes small. Further, if it exceeds the above range, the void space is small, and the internal pressure rises due to the expansion of the member due to the high temperature of the battery and the increase of the vapor pressure of the liquid component of the electrolyte, and the charge / discharge repetition performance as a battery. In some cases, various characteristics such as high temperature storage may be deteriorated, and a gas discharge valve that releases internal pressure to the outside may operate.

<Current collector structure>
The current collecting structure is not particularly limited, but in order to more effectively improve the discharge characteristics by the non-aqueous electrolyte solution of the present invention, it is necessary to use a structure that reduces the resistance of the wiring portion and the joint portion. preferable. When the internal resistance is reduced in this way, the effect of using the non-aqueous electrolytic solution of the present invention is particularly well exhibited.

When the electrode group has the above-mentioned laminated structure, a structure formed by bundling the metal core portions of each electrode layer and welding them to the terminals is preferably used. When the area of one electrode becomes large, the internal resistance becomes large. Therefore, it is also preferably used to reduce the resistance by providing a plurality of terminals in the electrode. In the case where the electrode group has the above-mentioned winding structure, the internal resistance can be reduced by providing a plurality of lead structures on the positive electrode and the negative electrode and bundling them in the terminals.

[Exterior case]
The non-aqueous electrolyte battery of the present invention is usually configured by accommodating the above-mentioned non-aqueous electrolyte, negative electrode, positive electrode, separator and the like in an exterior case (exterior body). There are no restrictions on this exterior case, and known ones can be arbitrarily adopted as long as the effects of the present invention are not significantly impaired.

The material of the outer case of the non-aqueous electrolyte battery is not particularly limited as long as it is a substance stable to the non-aqueous electrolyte used. Specifically, a nickel-plated steel plate, a metal such as stainless steel, aluminum or an aluminum alloy, nickel, titanium, or a magnesium alloy, or a laminated film (laminated film) of a resin and an aluminum foil is used. From the viewpoint of weight reduction, aluminum or aluminum alloy metal or laminated film is preferably used.

In the outer case using the metals, the metals are welded together by laser welding, resistance welding, or ultrasonic welding to form a sealed and sealed structure, or the metal is caulked using the metals via a resin gasket. There is something to do. Examples of the outer case using the laminated film include a case in which resin layers are heat-sealed to form a sealed and sealed structure. In order to improve the sealing property, a resin different from the resin used for the laminated film may be interposed between the resin layers. In particular, when the resin layer is heat-sealed via the current collector terminal to form a closed structure, the metal and the resin are bonded to each other. Resin is preferably used.

The shape of the outer case is also arbitrary, and may be, for example, any of a cylindrical type, a square shape, a laminated type, a coin type, a large size, and the like.

[Protective element]
The non-aqueous electrolyte battery of the present invention has PTC (Positive Temperature Coefficient), temperature fuse, thermistor, and battery internal pressure and internal temperature as protective elements that increase resistance when abnormal heat generation or excessive current flows. A valve (current cutoff valve) or the like that cuts off the current flowing through the circuit due to a sudden rise in the temperature may be provided. It is preferable to select the protective element under conditions that do not operate under normal use with a high current, and from the viewpoint of high output, it is more preferable to design the protective element so as not to cause abnormal heat generation or thermal runaway even without the protective element.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded.

The structures of the aromatic carboxylic acid ester (1) used in the following examples and the compound used in the comparative example are shown below.

[Example 1]
<Preparation of non-aqueous electrolyte solution>
Under a dry argon atmosphere, LiPF ₆ is adjusted to 1.2 mol / L in a non-aqueous solvent in which ethylene carbonate, ethyl methyl carbonate, and diethyl carbonate are mixed so as to be 30% by volume, 40% by volume, and 30% by volume, respectively. Dissolved in. Further, 2.0% by mass of vinylene carbonate and 2.0% by mass of monofluoroethylene carbonate were added. This is called "reference electrolyte 1".

To the reference electrolytic solution 1, 0.5% by mass of adiponitrile and 0.4% by mass of compound (A) were further added to prepare a non-aqueous electrolytic solution of Example 1.

<Manufacturing of positive electrode>
N-Methylpyrrolidone contains 97% by mass of lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, 1.5% by mass of acetylene black as a conductive material, and 1.5% by mass of polyvinylidene fluoride (PVdF) as a binder. It was mixed with a disperser in a solvent to form a slurry. This was uniformly applied to both sides of an aluminum foil having a thickness of 15 μm, dried, and then pressed to obtain a positive electrode.

<Manufacturing of negative electrode>
Aqueous dispersion of natural graphite powder as a negative electrode active material, sodium carboxymethyl cellulose as a thickener (concentration of sodium carboxymethyl cellulose 1% by mass), and aqueous dispersion of styrene butadiene rubber as a binder (concentration of styrene butadiene rubber 50% by mass). ) Was added and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a copper foil having a thickness of 10 μm, dried, and then pressed to obtain a negative electrode. In the negative electrode after drying, the mass ratio was such that natural graphite: sodium carboxymethyl cellulose: styrene butadiene rubber = 98: 1: 1.

<Manufacturing of lithium secondary battery>
The above positive electrode, negative electrode, and polypropylene separator were laminated in this order of negative electrode, separator, positive electrode, separator, and negative electrode to prepare a battery element. This battery element is inserted into a bag made of a laminated film in which both sides of aluminum (thickness 40 μm) are coated with a resin layer while projecting positive and negative terminals, and then a non-aqueous electrolyte solution is injected into the bag. Vacuum sealing was performed to produce a sheet-shaped lithium secondary battery.

Using the lithium secondary battery produced above, the following initial charge / discharge test and high temperature storage durability test were carried out. The evaluation results are shown in Table 1.
In Table 1, adiponitrile is abbreviated as "AdpCN", and succinonitrile used in the comparative example is abbreviated as "SN".

[Initial charge / discharge test (initial capacity)]
With the lithium secondary battery sandwiched between glass plates and pressurized, the lithium secondary battery was charged at a constant current of 0.05 C for 6 hours at 25 ° C., and then discharged at a constant current of 0.2 C to 3.0 V. Further, after constant current-constant voltage charging (also referred to as "CC-CV charging") (0.05C cut) up to 4.1V with a current corresponding to 0.2C, the mixture was left at 45 ° C. for 72 hours. .. Then, it was discharged to 3.0V with a constant current of 0.2C. Then, after CC-CV charging (0.05C cut) to 4.4V at 0.2C, it was discharged again to 3.0V at 0.5C, and this was used as the initial capacity. Here, 1C represents a current value for discharging the reference capacity of the battery in 1 hour, and 0.2C represents, for example, a current value of 1/5 of that.

[High temperature storage durability test (capacity after storage, high rate capacity after storage)]
The lithium secondary battery subjected to the initial charge / discharge was CC-CV charged (0.05C cut) at 0.2C to 4.4V at 25 ° C. Then, it was stored at a high temperature at 85 ° C. for 1 day. Then, at 25 ° C., a constant current was discharged to 3.0 V at 0.2 C. Then, after CC-CV charging (0.05C cut) to 4.4V at a constant current of 0.2C at 25 ° C., the battery was discharged again to 3.0V at 0.5C, and this was used as the capacity after storage. Further, CC-CV charging (0.05C cut) was performed at 0.2C to 4.4V, and then discharged to 3.0V at 1.0C, which was used as a high-rate capacity after storage.

[Example 2]
A lithium secondary battery was prepared in the same manner as in Example 1 except that a non-aqueous electrolytic solution containing 0.5% by mass of adiponitrile and 0.8% by mass of compound (A) was further added to the reference electrolytic solution 1. Then, the above evaluation was carried out.

[Example 3]
A lithium secondary battery was prepared in the same manner as in Example 1 except that a non-aqueous electrolytic solution containing 0.5% by mass of adiponitrile and 0.5% by mass of compound (B) was used as the reference electrolytic solution 1. Then, the above evaluation was carried out.

[Example 4]
A lithium secondary battery was prepared in the same manner as in Example 1 except that a non-aqueous electrolytic solution containing 0.5% by mass of adiponitrile and 1.0% by mass of compound (B) was further added to the reference electrolytic solution 1. Then, the above evaluation was carried out.

[Comparative Example 1]
A lithium secondary battery was prepared in the same manner as in Example 1 except that a non-aqueous electrolytic solution containing 0.5% by mass of adiponitrile and 0.4% by mass of compound (C) was further added to the reference electrolytic solution 1. , The above evaluation was carried out.

[Comparative Example 2]
A lithium secondary battery was used in the same manner as in Example 1 except that a non-aqueous electrolytic solution containing 0.5% by mass of succinonitrile and 0.4% by mass of compound (C) was used as the reference electrolytic solution 1. It was prepared and the above evaluation was carried out.

[Comparative Example 3]
A lithium secondary battery was used in the same manner as in Example 1 except that a non-aqueous electrolytic solution containing 0.5% by mass of succinonitrile and 0.4% by mass of compound (A) was used as the reference electrolytic solution 1. It was prepared and the above evaluation was carried out.

[Comparative Example 4]
A lithium secondary battery was used in the same manner as in Example 1 except that a non-aqueous electrolytic solution containing 0.5% by mass of succinonitrile and 0.5% by mass of compound (B) was used as the reference electrolytic solution 1. It was prepared and the above evaluation was carried out.

From Table 1, when the non-aqueous electrolytic solutions of Examples 1 to 4 according to the present invention are used, the initial capacity is impaired as compared with the case where the aromatic carboxylic acid ester (1) is not added together with adiponitrile (Comparative Example 1). It can be seen that the post-storing capacity and the post-storing high-rate capacity are improved without any problem. Further, when the non-aqueous electrolytic solutions of Examples 1 to 4 were used, the initial capacity was compared with the case where the aromatic carboxylic acid ester (1) was added together with succinonitrile, which is an additive other than adiponitrile (Comparative Examples 3 and 4). It can be seen that the post-storing capacity and the post-storing high-rate capacity are improved with almost no loss.
In Examples 1 to 4 and Comparative Examples 1 to 4, various evaluations were model-based short-term durability tests, but the actual use of the non-aqueous electrolyte secondary battery lasts for several years. In some cases, the difference in the results of the high-rate capacity after storage is even more remarkable, especially when long-term use is assumed.
As described above, by adding the aromatic carboxylic acid ester (1) together with adiponitrile according to the present invention, the decomposition of the non-aqueous electrolyte solution is suppressed, and the electrochemical side reaction of the decomposed product on the electrode is suppressed. The existence of a synergistic effect was suggested.
Therefore, it is clear that the non-aqueous electrolyte battery using the non-aqueous electrolytic solution of the present invention has excellent characteristics.

The non-aqueous electrolyte solution of the present invention is useful because it can improve the charge / discharge efficiency and rate characteristics of an energy device such as a non-aqueous electrolyte battery containing a non-aqueous electrolyte solution after a high temperature storage durability test. .. Therefore, the non-aqueous electrolyte solution and the non-aqueous electrolyte battery of the present invention can be used for various known applications. Specific examples include, for example, laptop computers, pen input computers, mobile computers, electronic book players, mobile phones, mobile fax machines, mobile copies, mobile printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, and mini discs. , Transceivers, electronic organizers, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, automobiles, bikes, motorized bicycles, bicycles, lighting equipment, toys, game equipment, watches, power tools, strobes, cameras, homes Examples include a backup power supply for personal computers, a backup power supply for business establishments, a power supply for load leveling, and a natural energy storage power supply.

Claims (9)

A non-aqueous electrolyte solution for a non-aqueous electrolyte battery having a positive electrode and a negative electrode capable of storing and releasing metal ions, wherein the non-aqueous electrolyte solution is fragrant represented by the following formula (1) together with an electrolyte and a non-aqueous solvent. A non-aqueous electrolyte solution containing a group carboxylic acid ester and further containing an adiponitrile.

(In the formula (1), R ¹ represents a saturated hydrocarbon group having 1 to 12 carbon atoms which may have a substituent, and R ² and R ³ each independently have a fluorine atom or a substituent. It may be a hydrocarbon group having 1 to 12 carbon atoms and may be bonded to each other to form a ring. A may be substituted with a hydrocarbon group having 1 to 12 carbon atoms or a fluorine atom. It is a good alkoxy group having 1 to 12 carbon atoms, a fluorine atom, or a substituent containing a fluorine atom, and m is an integer of 1 to 5. When m is 2 or more, a plurality of A's may be the same as each other. They may be very different, or the two A's may be bonded to each other to form a ring that condenses with a benzene ring having an A.) Claim 1 in the formula (1), wherein A is a hydrocarbon group having 4 to 12 carbon atoms, and the carbon atom bonded to the benzene ring of the hydrocarbon group is a quaternary carbon atom. The non-aqueous electrolyte solution described in 1. The non-aqueous electrolyte solution according to claim 1, wherein A is a fluorine atom or a substituent containing a fluorine atom in the formula (1). The non-aqueous electrolyte solution according to any one of claims 1 to 3, wherein R ² and R ³ are independent hydrocarbon groups having 1 to 12 carbon atoms in the formula (1). .. The invention according to any one of claims 1 to 4, wherein the aromatic carboxylic acid ester represented by the formula (1) is contained in a non-aqueous electrolytic solution in an amount of 0.001 to 10% by mass. Non-aqueous electrolyte solution. The non-aqueous electrolytic solution according to any one of claims 1 to 5, wherein the adiponitrile is contained in the non-aqueous electrolytic solution in an amount of 0.001 to 10% by mass. The non-aqueous electrolytic solution according to any one of claims 1 to 6, wherein the non-aqueous electrolytic solution further contains at least one compound selected from a cyclic carbonate having a fluorine atom. The non-aqueous electrolyte according to any one of claims 1 to 7, wherein the non-aqueous electrolyte solution further contains at least one compound selected from a cyclic carbonate having a carbon-carbon unsaturated bond. Electrolyte. A non-aqueous electrolyte battery containing a positive electrode and a negative electrode, and the non-aqueous electrolyte solution according to any one of claims 1 to 8.