JP2022135234A - Nonaqueous electrolyte solution and nonaqueous electrolyte secondary battery having the same - Google Patents

Abstract

To provide a nonaqueous electrolyte solution by which DCR increase of a nonaqueous electrolyte secondary battery after having been stored at a high temperature can be suppressed.SOLUTION: A nonaqueous electrolyte solution comprises: a compound (A) represented by the formula (I) below; and at least one compound (B) selected from a group consisting of a phosphate having a P-F bond and a P=O bond, a sulfonate having a S-F bond, and a borate having a B-F bond and/or an oxalate group. (In the formula (I), R1 to R6 independently represent a hydrogen atom, a halogen atom or a hydrocarbon group; of combinations of R1 and R2, R1 and R3, R4 and R5, and R5 and R6, constituents of each combination may be bound to each other to form a cyclic structure; and n is an integer of 0-4.)SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a non-aqueous electrolyte and a non-aqueous electrolyte secondary battery comprising the non-aqueous electrolyte.

Lithium non-aqueous electrolyte secondary batteries that use a lithium-containing transition metal oxide for the positive electrode and a non-aqueous solvent for the electrolyte can achieve high energy density. It is used in a wide range of applications, including large power supplies for railroads, railroads, and load leveling. However, in recent years, there has been an increasing demand for higher performance of non-aqueous electrolyte secondary batteries, and there is a strong demand for improvements in various characteristics.

So far, methods have been proposed to improve the battery characteristics of energy devices by including specific additives in the electrolyte or by combining specific electrolytes and electrodes. For example, Patent Document 1 relates to an electrolytic solution for an electric storage device, particularly a lithium ion storage battery containing a Si-based negative electrode active material, and a negative electrode containing a Si-based negative electrode active material and a specific carbon-carbon double bond. It has been proposed to improve the discharge capacity retention rate during cycling of an electricity storage device by providing a non-aqueous electrolytic solution containing an ester compound having a

Patent Document 2 proposes an electrolytic solution containing a specific saturated chain carboxylic acid ester and an unsaturated chain carboxylic acid ester in order to improve the discharge capacity retention rate in charge-discharge cycles of a non-aqueous electrolyte battery. ing.

In Patent Document 3, in order to improve the discharge capacity retention rate during cycling while suppressing the expansion of the battery during high-temperature storage, the electrolyte contains a specific unsaturated carboxylic acid ester, and a specific exterior member It has been proposed that the non-aqueous electrolyte secondary battery is made by housing the non-aqueous electrolyte secondary battery.

Patent Document 4 proposes a non-aqueous electrolytic solution containing a specific polymerizable organic compound in order to improve high-temperature characteristics and storage characteristics in a lithium secondary battery using spinel-type lithium manganate as a positive electrode active material. ing.

WO2019-113528 Japanese Patent Application Laid-Open No. 2007-335170 JP 2009-152133 A JP-A-2000-223154

In recent years, non-aqueous electrolyte secondary batteries have been required to have higher and higher performance, especially for battery-equipped vehicles, and a high level of improvement in battery capacity after high-temperature storage has been demanded. So far, for example, phosphates such as lithium difluorophosphate have been studied as additives for non-aqueous electrolyte secondary batteries.
However, in Patent Document 1, a negative electrode containing a specific negative electrode active material and a non-aqueous electrolyte containing an ester compound having a carbon-carbon double bond are combined. Although the improvement of the retention rate has been studied, the battery resistance after high-temperature storage has not been paid attention to and studied. Further, in Patent Literature 2, improvement of the discharge capacity retention rate during the cycle test is studied, but the battery resistance after high-temperature storage is not paid attention to and studied. Furthermore, in Patent Document 3, improvement of cycle characteristics is studied by combining a specific exterior member and an electrolytic solution having a specific unsaturated carboxylic acid ester, but an electrolytic solution other than the specific unsaturated carboxylic acid ester is used. It only states that the components include a solvent and an electrolyte salt dissolved in the solvent, and that it preferably includes a halogenated carbonate or a carbonate having a carbon-carbon multiple bond. Furthermore, in Patent Document 4, it is studied to improve the discharge capacity retention rate in charge-discharge cycles by selecting an additive suitable for the saturated chain carboxylic acid ester, but as a component of the non-aqueous electrolyte , other than specific saturated and unsaturated linear carboxylic acid esters, are only described to include a solvent and an electrolyte salt dissolved in the solvent.

An object of the present invention is to provide a non-aqueous electrolyte that can suppress an increase in direct current resistance (DCR) of a non-aqueous electrolyte secondary battery after high-temperature storage.

As a result of intensive studies to solve the above problems, the present inventors have found that an ester compound having a specific carbon-carbon unsaturated bond in a non-aqueous electrolytic solution, and a specific phosphate, sulfonate or borate By containing, it was found that the above problems can be solved, and the present invention was achieved.

（式（Ｉ）中、Ｒ^１～Ｒ^６は、それぞれ独立に、水素原子、ハロゲン原子、又は炭化水素基であり、Ｒ^１とＲ^２、Ｒ^１とＲ^３、Ｒ^４とＲ^５、及びＲ^５とＲ^６は互いに結合し環状構造を形成していてもよい。ｎは０～４の整数である。）
［２］前記式（Ｉ）中、Ｒ^１～Ｒ^６が、それぞれ独立に、水素原子、ハロゲン原子、炭素数１～６のアルキル基、炭素数２～６のアルケニル基、炭素数６～１２のアリール基、又は炭素数７～１８のアラルキル基である、［１］に記載の非水系電解液。
［３］前記式（Ｉ）で表される化合物（Ａ）が、下記式（ＩＩ）で表されるビニルエステル化合物及び／又は式（ＩＩＩ）で表されるアリルエステル化合物である、［１］又は［２］に記載の非水電解液。

（式（ＩＩ）中、Ｒ^７～Ｒ^９は、それぞれ独立に、水素原子、ハロゲン原子、又は炭化水素基であり、Ｒ^７とＲ^８、Ｒ^７とＲ^９は互いに結合し環状構造を形成していてもよい。）

（式（ＩＩＩ）中、Ｒ^１０～Ｒ^１２は、それぞれ独立に、水素原子、ハロゲン原子、又は炭化水素基であり、Ｒ^１０とＲ^１１、Ｒ^１０とＲ^１２は互いに結合し環状構造を形成していてもよい。）
［４］前記式（Ｉ）で表される化合物（Ａ）がメタクリル酸アリルである、［１］～［３］のいずれかに記載の非水系電解液。
［５］前記式（Ｉ）で表される化合物（Ａ）を０．０１質量％以上、１０質量％以下含有する、［１］～［４］のいずれかに記載の非水系電解液。
［６］前記Ｐ－Ｆ結合及びＰ＝Ｏ結合を有するリン酸塩、Ｓ－Ｆ結合を有するスルホン酸塩、Ｂ－Ｆ結合を有するホウ酸塩及びオキサラート基を有するホウ酸塩からなる群より選ばれる１種以上の化合物（Ｂ）を、０．０１質量％以上、１０質量％以下含有する、［１］～［５］のいずれかに記載の非水系電解液。
［７］金属イオンを吸蔵及び放出しうる正極活物質を有する正極と、金属イオンを吸蔵及び放出しうる負極活物質を有する負極と、［１］～［６］のいずれかに記載の非水系電解液と、を備える非水系電解液二次電池。 That is, the gist of the present invention resides in the following.
[1] a compound (A) represented by formula (I), a phosphate having a PF bond and a P=O bond, a sulfonate having an SF bond, and a BF bond and/or and one or more compounds (B) selected from the group consisting of borates having an oxalate group.

(In Formula (I), R ¹ to R ⁶ are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group, and R ¹ and R ² , R ¹ and R ³ , R ⁴ and R ⁵ , and R ⁵ and R ⁶ may combine with each other to form a cyclic structure, and n is an integer of 0 to 4.)
[2] In formula (I), R ¹ to R ⁶ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or 6 to 12 carbon atoms. or an aralkyl group having 7 to 18 carbon atoms, the non-aqueous electrolytic solution according to [1].
[3] The compound (A) represented by the formula (I) is a vinyl ester compound represented by the following formula (II) and/or an allyl ester compound represented by the formula (III) [1] Or the non-aqueous electrolytic solution according to [2].

(In Formula (II), R ⁷ to R ⁹ are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group, and R ⁷ and R ⁸ and R ⁷ and R ⁹ are bonded to each other to form a cyclic structure. may be.)

(In Formula (III), R ¹⁰ to R ¹² are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group, and R ¹⁰ and R ¹¹ and R ¹⁰ and R ¹² are bonded to each other to form a cyclic structure. may be.)
[4] The non-aqueous electrolytic solution according to any one of [1] to [3], wherein the compound (A) represented by formula (I) is allyl methacrylate.
[5] The non-aqueous electrolytic solution according to any one of [1] to [4], containing 0.01% by mass or more and 10% by mass or less of the compound (A) represented by the formula (I).
[6] from the group consisting of a phosphate having a PF bond and a P=O bond, a sulfonate having an SF bond, a borate having a BF bond and a borate having an oxalate group The non-aqueous electrolytic solution according to any one of [1] to [5], containing 0.01% by mass or more and 10% by mass or less of one or more selected compounds (B).
[7] A positive electrode having a positive electrode active material capable of absorbing and releasing metal ions, a negative electrode having a negative electrode active material capable of absorbing and releasing metal ions, and the non-aqueous system according to any one of [1] to [6]. A non-aqueous electrolyte secondary battery comprising an electrolyte.

ADVANTAGE OF THE INVENTION According to this invention, the non-aqueous electrolyte solution which can suppress the increase in DCR of the non-aqueous electrolyte secondary battery after high temperature storage can be provided. Also, a non-aqueous electrolyte secondary battery comprising the non-aqueous electrolyte can be provided.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated in detail. However, the description given below is an example (representative example) of the embodiment of the present invention, and the present invention is not limited to these contents. In addition, the present invention can be arbitrarily changed and implemented without departing from the gist thereof.

（式（Ｉ）中、Ｒ^１～Ｒ^６は、それぞれ独立に、水素原子、ハロゲン原子、又は炭化水素基であり、Ｒ^１とＲ^３、又はＲ^４とＲ^５は互いに結合し環状構造を形成していてもよい。ｎは０～４の整数である。）
本発明に係る非水系電解液は、高温保存後の電池容量を改善し得る。このような優れた
効果を奏する理由について、本発明者は以下のように推測する。
二次電池の充放電に伴い、式（Ｉ）で表される化合物（Ａ）の炭素－炭素不飽和結合が電極上で反応して化合物（Ａ）が多量化し、さらにＰ－Ｆ結合及びＰ＝Ｏ結合を有するリン酸塩、Ｓ－Ｆ結合を有するスルホン酸塩、並びにＢ－Ｆ結合及び／又はオキサラート基を有するホウ酸塩からなる群より選ばれる１種以上の化合物（Ｂ）と反応し、電極上で難溶解性かつ強固な共被膜を形成することで、電極活物質と溶媒等との副反応を抑制すると考える。
すなわち、本発明は、非水系電解液中に、炭素－炭素不飽和結合を有するエステル化合物とＰ－Ｆ結合及びＰ＝Ｏ結合を有するリン酸塩、Ｓ－Ｆ結合を有するスルホン酸塩、並びにＢ－Ｆ結合及び／又はオキサラート基を有するホウ酸塩からなる群より選ばれる１種以上の化合物とを含有させることで、従来より高いレベルまで、高温保存後のＤＣＲ増加を抑制できると考える。
以下、各構成について説明する。 [1. Non-aqueous electrolyte]
The non-aqueous electrolyte used in the non-aqueous electrolyte secondary battery according to the embodiment of the present invention contains an electrolyte, a non-aqueous solvent for dissolving it, as well as a general non-aqueous electrolyte, and further has the formula ( Compound (A) represented by I) (hereinafter sometimes referred to as an ester compound having a carbon-carbon unsaturated bond), and a phosphate having a PF bond and a P=O bond, and an SF bond and one or more compounds (B) selected from the group consisting of sulfonates having It is a non-aqueous electrolytic solution containing.

(In Formula (I), R ¹ to R ⁶ are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group, and R ¹ and R ³ or R ⁴ and R ⁵ are bonded to each other to form a cyclic structure. may be formed, n is an integer from 0 to 4.)
The non-aqueous electrolytic solution according to the present invention can improve battery capacity after high-temperature storage. The inventor of the present invention presumes the reason for such excellent effects as follows.
As the secondary battery is charged and discharged, the carbon-carbon unsaturated bond of the compound (A) represented by the formula (I) reacts on the electrode to increase the amount of the compound (A), and further the PF bond and P = reacting with one or more compounds (B) selected from the group consisting of phosphates having an O bond, sulfonates having an SF bond, and borates having a BF bond and/or an oxalate group However, it is thought that side reactions between the electrode active material and the solvent or the like can be suppressed by forming a hard and insoluble co-film on the electrode.
That is, the present invention provides, in a non-aqueous electrolytic solution, an ester compound having a carbon-carbon unsaturated bond, a phosphate having a PF bond and a P=O bond, a sulfonate having an SF bond, and By containing one or more compounds selected from the group consisting of borates having a BF bond and/or an oxalate group, it is believed that the increase in DCR after high-temperature storage can be suppressed to a higher level than before.
Each configuration will be described below.

[1-1. Compound (A) represented by formula (I) (carbon-carbon ester compound having unsaturated bond)]

In formula (I), R ¹ to R ⁶ are each independently a hydrogen atom, a halogen atom or a hydrocarbon group.
A halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. Among them, a fluorine atom is preferable from the viewpoint of stability to the electrolytic solution.
Hydrocarbon groups include alkyl groups, alkenyl groups, alkynyl groups, aryl groups and aralkyl groups. Among them, an alkyl group, an alkenyl group, an aryl group, and an aralkyl group are preferable, an alkyl group and an alkenyl group are more preferable, and an alkyl group is particularly preferable. Incidentally, the hydrocarbon group may have a substituent such as a fluorine atom. Aryl groups are also meant to include heteroaryl groups in which any ring atom is substituted with a heteroatom.
Alkyl groups include methyl, ethyl, n-propyl, iso-propyl, n-butyl, tert-butyl, n-pentyl, hexyl, heptyl, octyl, nonyl, and decyl. and the like. Among them, an alkyl group having 1 to 6 carbon atoms is preferable from the standpoint of solubility in the electrolytic solution.
Examples of alkenyl groups include vinyl, allyl, methallyl, 2-butenyl, 3-methyl-2-butenyl, 3-butenyl, 4-pentenyl, 5-hexenyl, 6-heptenyl, and 7- An octenyl group and the like can be mentioned. Among them, an alkenyl group having 2 to 6 carbon atoms is preferable in terms of solubility in the electrolytic solution.
Examples of alkynyl groups include ethynyl, 2-propynyl, 2-butynyl, 3-butynyl, 4-pentynyl, 5-hexynyl, 6-heptynyl, and 7-octynyl groups. Among them, an alkynyl group having 2 to 6 carbon atoms is preferable from the standpoint of solubility in the electrolytic solution.
Aryl groups include phenyl, 1-naphthyl, 2-naphthyl, 2-thienyl, 3-thienyl, 2-furyl, 3-furyl, 2-pyrrolyl, 3-pyrrolyl, and benzyl and the like. Among them, an aryl group having 6 to 12 carbon atoms is preferable, and a phenyl group, a 1-naphthyl group and a 2-naphthyl group are particularly preferable from the viewpoint of solubility in the electrolytic solution.
The aralkyl group includes a phenylmethyl group (benzyl group), a phenylethyl group (phenethyl group), a phenylpropyl group, a phenylbutyl group, a phenylisopropyl group, and the like. Among them, a benzyl group and a phenethyl group are preferable, and a benzyl group is particularly preferable from the viewpoint of stability to the electrolytic solution.
R ¹ and R ² , R ¹ and R ³ , R ⁴ and R ⁵ , or R ⁵ and R ⁶ in formula (I) may be bonded to each other to form a cyclic structure. ^In the present ^{specification , R 1} to ^{R 6 are one C--} It also includes groups generated when the C bond is cleaved.
The cyclic structure composed of R ¹ , R ² and the carbon to which R ¹ and R ² are bonded, or the carbon to which R ⁵ , R ⁶ and R ⁵ and R ⁶ are bonded includes an alicyclic ring such as a cyclohexene ring and a cyclopentene ring. Formula carbocycles are included. Among them, a cyclohexene ring is preferable from the viewpoint of stability to the electrolytic solution.
R ¹ , R ³ and a carbon-carbon double bond between the carbon to which R ¹ and R ² are bonded and the carbon to which R ³ and the ester group are bonded, R ⁴ , R ⁵ and R ⁴ and a methylene or ester group The cyclic structure composed of a carbon-carbon double bond between the carbon to which the oxygen atom of and the carbon to which R ⁵ and R ⁶ are bonded includes an alicyclic carbocyclic ring such as a cyclohexene ring and a cyclopentene ring; a benzene ring, aromatic rings such as naphthalene ring; and the like. Among them, a cyclohexene ring, a benzene ring, and a naphthalene ring are preferable from the viewpoint of stability to an electrolytic solution, a cyclohexene ring, a benzene ring, and a naphthalene ring are more preferable, and a cyclohexene ring and a benzene ring are even more preferable. Also, hydrogen atoms in the ring structure may be substituted with halogen atoms such as fluorine atoms.
R ¹ to R ⁶ are preferably a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
n is an integer of 0 to 4, preferably an integer of 0 to 2, more preferably 0 or 1, and still more preferably 1 from the viewpoint of solubility in the electrolytic solution.

（式（ＩＩ）中、Ｒ^７～Ｒ^９は、それぞれ独立に、水素原子、ハロゲン原子、又は炭化水素基であり、Ｒ^７とＲ^８、Ｒ^７とＲ^９は互いに結合し環状構造を形成していてもよい。）

（式（ＩＩＩ）中、Ｒ^１０～Ｒ^１２は、それぞれ独立に、水素原子、ハロゲン原子、又は炭化水素基であり、Ｒ^１０とＲ^１１、Ｒ^１０とＲ^１２は互いに結合し環状構造を形成していてもよい。）
一般式（ＩＩ）におけるＲ^７～Ｒ^９、及び一般式（ＩＩＩ）におけるＲ^１０～Ｒ^１２は、それぞれ一般式（Ｉ）におけるＲ^１～Ｒ^３と同義である。 From the viewpoint of stability in the electrolytic solution, vinyl ester compounds represented by the following general formula (II) and/or allyl ester compounds represented by general formula (III) are more preferred.

(In Formula (II), R ⁷ to R ⁹ are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group, and R ⁷ and R ⁸ and R ⁷ and R ⁹ are bonded to each other to form a cyclic structure. may be.)

(In Formula (III), R ¹⁰ to R ¹² are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group, and R ¹⁰ and R ¹¹ and R ¹⁰ and R ¹² are bonded to each other to form a cyclic structure. may be.)
R ⁷ to R ⁹ in general formula (II) and R ¹⁰ to R ¹² in general formula (III) have the same definitions as R ¹ to R ³ in general formula (I).

Specific examples of the compound represented by formula (I) include the following compounds.

Among them, the following compounds are preferable.

More preferred are the following compounds.

More preferred are the following compounds.

The following compounds are more preferred.

The following compounds are more preferred. This is because excessive reaction on the electrode can be suppressed.

The content of the compound represented by formula (I) is not particularly limited, but is usually 0.01% by mass or more, preferably 0.05% by mass or more, relative to the total amount of the non-aqueous electrolytic solution, Also, it is usually 10% by mass or less, preferably 8% by mass or less, more preferably 6% by mass or less, and still more preferably 4% by mass or less. The compounds represented by formula (I) may be used singly or two or more may be used in any combination and ratio.
Identification and content measurement of the ester compound having a carbon-carbon unsaturated bond are performed by nuclear magnetic resonance (NMR) spectroscopy.

[1-2. Phosphate having PF bond and P=O bond, sulfonate having SF bond, borate having BF bond and/or oxalate group: compound (B) (combined additive)]
[1-2-1. Phosphate with PF bond and P=O bond]
Phosphates having a PF bond and a P=O bond are not particularly limited, but specific examples include lithium monofluorophosphate, sodium monofluorophosphate, potassium monofluorophosphate, rubidium monofluorophosphate, mono Cesium fluorophosphate, lithium difluorophosphate, sodium difluorophosphate, potassium difluorophosphate, rubidium difluorophosphate, cesium difluorophosphate, lithium monofluoromonomethyl phosphate, sodium monofluoromonomethyl phosphate, potassium monofluoromonomethyl phosphate , rubidium monofluoromonomethyl phosphate, and cesium monofluoromonomethyl phosphate. Among them, lithium monofluorophosphate and lithium difluorophosphate are particularly preferable in terms of electrolyte solution stability.
The content of the phosphate having a PF bond and a P=O bond is not particularly limited, but is usually 0.01% by mass or more, preferably 0.05% by mass, based on the total amount of the non-aqueous electrolyte. Above, more preferably 0.1% by mass or more, and usually 10% by mass or less, preferably 8% by mass or less, more preferably 6% by mass or less. Phosphate having PF bond and P=O bond is identified and its content is measured by nuclear magnetic resonance (NMR) spectroscopy.

[1-2-2. Sulfonate with SF bond]
The sulfonate having an SF bond is not particularly limited, but specific examples include fluorosulfonic acids such as lithium fluorosulfonate, sodium fluorosulfonate, potassium fluorosulfonate, rubidium fluorosulfonate, and cesium fluorosulfonate. salts; fluorosulfonylimide salts such as bisfluorosulfonylimide lithium; and the like. Fluorosulfonate is preferable, and lithium fluorosulfonate is more preferable from the viewpoint of electrolyte solution stability.
The content of the sulfonate having an SF bond is not particularly limited, but is usually 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0, based on the total amount of non-aqueous electrolysis. .1% by mass or more, and usually 10% by mass or less, preferably 8% by mass or less, more preferably 6% by mass or less.

[1-2-3. Borate with BF bond and/or oxalate group]
The borate having a BF bond and/or an oxalate group of the present invention is not particularly limited, but specific examples include lithium tetrafluoroborate, sodium tetrafluoroborate, potassium tetrafluoroborate, tetrafluoroborate Borates having a BF bond such as rubidium acid, cesium tetrafluoroborate, lithium trifluoromonomethylborate, lithium difluorodimethylborate, or lithium trimethylmonofluoroborate; lithium bisoxalate borate, bisoxa Borates having an oxalate group such as sodium oxalate borate, potassium bisoxalate borate, rubidium bisoxalate borate, or cesium bisoxalate borate; lithium monooxalate difluoroborate, monooxalate difluoroborate borates having a BF bond and an oxalate group, such as sodium, potassium monooxalate difluoroborate, or cesium monooxalate difluoroborate; Among them, lithium tetrafluoroborate, sodium tetrafluoroborate, potassium tetrafluoroborate, lithium bisoxalate borate, and lithium monooxalate difluoroborate are particularly preferable in terms of electrolyte solution stability.
The content of the borate having a BF bond and/or an oxalate group is not particularly limited, but is 0.01% by mass or more, preferably 0.05% by mass, based on the total amount of the non-aqueous electrolytic solution. Above, more preferably 0.1% by mass or more, and 10% by mass or less, preferably 8% by mass or less, and more preferably 6% by mass or less. The borate having a BF bond and/or an oxalate group is identified and its content is measured by nuclear magnetic resonance (NMR) spectroscopy.

A compound (B) selected from the group consisting of a phosphate having a PF bond and a P═O bond, a sulfonate having an SF bond, and a borate having a BF bond and/or an oxalate group The total content when two or more types are contained is usually 0.01% by mass or more, preferably 0.05% by mass or more, more preferably 0.1% by mass or more, relative to the total amount of the non-aqueous electrolytic solution. Also, it is usually 10% by mass or less, preferably 8% by mass or less, more preferably 6% by mass or less.

[1-3. Electrolytes]
<Lithium salt>
A lithium salt is usually used as the electrolyte in the non-aqueous electrolytic solution. The lithium salt is not particularly limited as long as it is known to be used for this purpose, and any lithium salt can be used. Specific examples include the following.

Examples include lithium fluoroborate salts, lithium fluorophosphate salts, lithium tungstate salts, lithium carboxylate salts, lithium sulfonate salts, lithium imide salts, lithium methide salts, lithium oxalate salts, and fluorine-containing organic lithium salts. .

LiBF ₄ as lithium fluoroborate; LiPF ₆ as lithium fluorophosphate; CH ₃ SO ₃ Li as lithium sulfonate; LiN(FSO ₂ ) (CF ₃ SO ₂ ), LiN(CF ₃ SO ₂ ) ₂ , LiN(C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide; ₂ ) ₃ , LiC(CF ₃ SO ₂ ) ₃ , LiC(C ₂ F ₅ SO ₂ ) ₃ ; lithium oxalate salts such as lithium monooxalate difluoroborate, lithium bisoxalate borate (LiBOB), lithium tetrafluoro Oxalatophosphate, lithium difluorobis(oxalato)phosphate, lithium tris(oxalato)phosphate, etc. have the effect of improving low-temperature output characteristics, high-rate charge/discharge characteristics, impedance characteristics, high-temperature storage characteristics, cycle characteristics, etc. more preferable from the point of view. LiPF ₆ or lithium bis(oxalato)borate is more preferred, and LiPF ₆ is particularly preferred. Moreover, the said electrolyte may be used independently or may use 2 or more types together. However, [1-2-1. Phosphate with PF bond and P=O bond] to [1-2-3. Borate with BF bond and/or oxalate group] When the non-aqueous electrolyte contains a lithium salt electrolyte that corresponds to the combined additive described above, it must contain an electrolyte other than the lithium salt that corresponds to the combined additive. do.
The combination of two or more electrolytes is not particularly limited, but preferably includes a combination of LiPF ₆ and LiBF ₄ and a combination of LiPF ₆ and LiN(CF ₃ SO ₂ ) ₂ . Among them, a combination of LiPF ₆ and LiBF ₄ is preferred.

The total concentration of the electrolyte in the non-aqueous electrolyte is not particularly limited, but is usually 8% by mass or more, preferably 8.5% by mass or more, more preferably 9% by mass or more, relative to the total amount of the non-aqueous electrolyte. and is usually 18% by mass or less, preferably 17% by mass or less, more preferably 16% by mass or less. When the total concentration of the electrolytes is within the above range, the electrical conductivity is appropriate for battery operation, so there is a tendency to obtain sufficient output characteristics. Identification of the electrolyte and measurement of the content are performed by nuclear magnetic resonance (NMR) spectroscopy.

[1-4. Non-aqueous solvent]
The non-aqueous electrolytic solution according to one embodiment of the present invention normally contains, as its main component, a non-aqueous solvent that dissolves the above-described electrolyte, like common non-aqueous electrolytic solutions. The non-aqueous solvent to be used is not particularly limited as long as it dissolves the electrolyte described above, and known organic solvents can be used. Examples of organic solvents include saturated cyclic carbonates, chain carbonates, chain carboxylic acid esters (excluding compounds represented by formula (I)), cyclic carboxylic acid esters, ether compounds, sulfone compounds, and the like. Examples include, but are not limited to, these. An organic solvent can be used individually by 1 type or in combination of 2 or more types.
The combination of two or more organic solvents is not particularly limited, but saturated cyclic carbonates and chain carboxylic acid esters, cyclic carboxylic acid esters and chain carbonates, and saturated cyclic carbonates, chain carbonates and chain carboxylic acid esters. is mentioned. Of these, saturated cyclic carbonates and chain carbonates, and saturated cyclic carbonates, chain carbonates and chain carboxylic acid esters are preferred.

[1-4-1. saturated cyclic carbonate]
Examples of saturated cyclic carbonates include those having an alkylene group having 2 to 4 carbon atoms, and saturated cyclic carbonates having 2 to 3 carbon atoms are preferably used from the viewpoint of improving battery characteristics resulting from an improvement in the degree of dissociation of lithium ions. be done.

Specific examples of saturated cyclic carbonates include ethylene carbonate, propylene carbonate, and butylene carbonate. Among them, ethylene carbonate or propylene carbonate is preferable, and ethylene carbonate which is difficult to be oxidized/reduced is more preferable. Saturated cyclic carbonates may be used alone, or two or more of them may be used in any combination and ratio.

The content of the saturated cyclic carbonate is not particularly limited, and is arbitrary as long as it does not significantly impair the effects of the invention according to the present embodiment. The content is preferably 5% by volume or more, and 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, it is possible to avoid a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte, and to improve the large current discharge characteristics of the non-aqueous electrolyte secondary battery, the stability to the negative electrode, and the cycle characteristics. range, the oxidation/reduction resistance of the non-aqueous electrolytic solution is improved, and the stability during high-temperature storage tends to be improved.
In addition, volume % in this embodiment means the volume at 25 degreeC and 1 atmospheric pressure.

[1-4-2. chain carbonate]
As the chain carbonate, those having 3 to 7 carbon atoms are usually used, and chain carbonates having 3 to 5 carbon atoms are preferably used in order to adjust the viscosity of the electrolytic solution within an appropriate range.

Specific examples of chain carbonates include dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethylmethyl carbonate and methyl-n-propyl carbonate. Particularly preferred are dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate.

Chain carbonates having a fluorine atom (hereinafter sometimes abbreviated as “fluorinated chain carbonate”) can also be preferably used. The number of fluorine atoms in the fluorinated linear carbonate is not particularly limited as long as it is 1 or more, but it is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, the plurality of fluorine atoms may be bonded to the same carbon or to different carbons.
Fluorinated linear carbonates include fluorinated dimethyl carbonate derivatives such as fluoromethylmethyl carbonate; fluorinated ethylmethyl carbonate derivatives such as 2-fluoroethylmethyl carbonate; and fluorinated diethyl carbonates such as ethyl-(2-fluoroethyl) carbonate. derivatives; and the like.

A chain carbonate may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

Although the content of the chain carbonate is not particularly limited, it is usually 15% by volume or more, preferably 20% by volume or more, more preferably 25% by volume or more, relative to the total amount of the non-aqueous solvent in the non-aqueous electrolyte, Also, it is usually 90% by volume or less, preferably 85% by volume or less, 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 is set in an appropriate range, the decrease in ionic conductivity is suppressed, and the output characteristics of the non-aqueous electrolyte secondary battery are kept in a good range. It becomes easier to

Furthermore, by combining a specific linear carbonate with a specific content of ethylene carbonate, the battery performance can be significantly improved.

For example, when dimethyl carbonate and ethyl methyl carbonate are selected as specific chain carbonates, the content of ethylene carbonate is not particularly limited, and is arbitrary as long as the effects of the invention according to the present embodiment are not significantly impaired. It is usually 15% by volume or more, preferably 20% by volume or more, and usually 45% by volume or less, preferably 40% by volume or less, based on the total amount of the non-aqueous solvent in the aqueous electrolyte. It is usually 20% by volume or more, preferably 30% by volume or more, and usually 50% by volume or less, preferably 45% by volume or less, based on the total amount of the non-aqueous solvent in the aqueous electrolyte. It is usually 20% by volume or more, preferably 30% by volume or more, and usually 50% by volume or less, preferably 45% by volume or less, relative to the total amount of the non-aqueous solvent in the aqueous electrolytic solution. By setting the content within the above range, there is a tendency that high-temperature stability is excellent and gas generation is suppressed.

[1-4-3. Chain carboxylic acid ester]
Chain carboxylic acid esters (excluding compounds represented by formula (I)) include, for example, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, Methyl butyrate, ethyl butyrate, methyl valerate, methyl isobutyrate, ethyl isobutyrate, and methyl pivalate. Among them, methyl acetate, ethyl acetate, propyl acetate, or butyl acetate is preferable from the viewpoint of improving battery characteristics. Chain carboxylic acid esters (eg, methyl trifluoroacetate, ethyl trifluoroacetate, etc.) obtained by substituting fluorine atoms for part of the hydrogen atoms in the above compounds can also be used favorably.
The content of the chain carboxylic acid ester is generally 1% by volume or more, preferably 5% by volume or more, more preferably 15% by volume or more, relative to the total amount of the non-aqueous solvent. Within this range, the electrical conductivity of the non-aqueous electrolytic solution is improved, and the large current discharge characteristics of the non-aqueous electrolytic solution battery are easily improved. Moreover, the content of the chain carboxylic acid ester is usually 70% by volume or less, preferably 50% by volume or less, and more preferably 40% by volume or less. By setting the upper limit in this way, the viscosity of the non-aqueous electrolyte solution can be adjusted to an appropriate range, a decrease in electrical conductivity can be avoided, an increase in negative electrode resistance can be suppressed, and a large current discharge of the non-aqueous electrolyte secondary battery can be achieved. It becomes easier to bring the characteristics into a favorable range.

[1-4-4. Cyclic carboxylic acid ester]
Cyclic carboxylic acid esters include, for example, γ-butyrolactone and γ-valerolactone. Among these, γ-butyrolactone is more preferred. Cyclic carboxylic acid esters obtained by substituting a portion of the hydrogen atoms of the above compounds with fluorine are also suitable for use.
The content of the cyclic carboxylic acid ester is generally 1% by volume or more, preferably 5% by volume or more, more preferably 15% by volume or more, relative to the total amount of the non-aqueous solvent in the non-aqueous electrolytic solution. Within this range, the electrical conductivity of the non-aqueous electrolytic solution is improved, and the large current discharge characteristics of the non-aqueous electrolytic solution battery are easily improved. Moreover, the content of the cyclic carboxylic acid ester is usually 70% by volume or less, preferably 50% by volume or less, more preferably 40% by volume or less, relative to the total amount of the non-aqueous solvent. By setting the upper limit in this way, the viscosity of the non-aqueous electrolyte solution can be adjusted to an appropriate range, a decrease in electrical conductivity can be avoided, an increase in negative electrode resistance can be suppressed, and a large current discharge of the non-aqueous electrolyte secondary battery can be achieved. It becomes easier to bring the characteristics into a good range.

[1-4-5. Ether-based compound]
The ether-based compound is not particularly limited, but a chain having 3 to 10 carbon atoms such as dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether, etc. ether; and carbon number such as tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,3-dioxane, 2-methyl-1,3-dioxane, 4-methyl-1,3-dioxane, 1,4-dioxane 3 to 6 cyclic ethers; are preferred. A portion of the hydrogen atoms in the above ether-based compound may be substituted with fluorine.
Among them, as a chain ether having 3 to 10 carbon atoms, dimethoxymethane and diethoxymethane have high solvation ability for lithium ions, improve ion dissociation, have low viscosity, and provide high ionic conductivity. , or ethoxymethoxymethane is preferable, and tetrahydrofuran, 1,3-dioxane, 1,4-dioxane, or the like is preferable as a cyclic ether having 3 to 6 carbon atoms because it gives a high degree of ionic conductivity.

The content of the ether-based compound is not particularly limited, and is arbitrary as long as it does not significantly impair the effects of the invention according to the present embodiment. It is preferably 2% by volume or more, more preferably 3% by volume or more, and usually 30% by volume or less, preferably 25% by volume or less, more preferably 20% by volume or less. When the content of the ether-based compound is within the above range, it is easy to secure the effect of improving the degree of dissociation of lithium ions and improving the ionic conductivity resulting from the decrease in viscosity. Moreover, when the negative electrode active material is a carbon-based material, the phenomenon of co-insertion of the chain ether together with the lithium ions can be suppressed, so that the input/output characteristics and the charge/discharge rate characteristics can be set within appropriate ranges.

[1-4-6. Sulfone compound]
The sulfone-based compound is not particularly limited, and may be a cyclic sulfone or a chain sulfone. Cyclic sulfones generally have 3 to 6 carbon atoms, preferably 3 to 5 carbon atoms, and chain sulfones generally have 2 to 6 carbon atoms, preferably 2 to 5 carbon atoms. Although the number of sulfonyl groups in one molecule of the sulfone compound is not particularly limited, it is usually one or two.

Cyclic sulfones include trimethylenesulfones, tetramethylenesulfones, hexamethylenesulfones, etc., which are monosulfone compounds; and trimethylenedisulfones, tetramethylenedisulfones, hexamethylenedisulfones, etc., which are disulfone compounds. Among them, tetramethylenesulfones, tetramethylenedisulfones, hexamethylenesulfones, or hexamethylenedisulfones are more preferable, and tetramethylenesulfones (sulfolanes) are particularly preferable from the viewpoint of dielectric constant and viscosity.

As sulfolanes, sulfolane and sulfolane derivatives are preferred. As the sulfolane derivative, one in which one or more hydrogen atoms bonded to carbon atoms constituting a sulfolane ring are substituted with a fluorine atom, an alkyl group, or a fluorine-substituted alkyl group is preferable.

Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3-fluorosulfolane, 2,3-difluorosulfolane, 2-trifluoromethylsulfolane, 3-trifluoromethylsulfolane and the like have high ionic conductivity. It is preferable in terms of high input/output.

Chain sulfones include dimethylsulfone, ethylmethylsulfone, diethylsulfone, monofluoromethylmethylsulfone, difluoromethylmethylsulfone, trifluoromethylmethylsulfone, pentafluoroethylmethylsulfone and the like. Among them, dimethylsulfone, ethylmethylsulfone, and monofluoromethylmethylsulfone are preferable because they improve the high-temperature storage stability of the electrolytic solution.

The content of the sulfone-based compound is not particularly limited, and is arbitrary as long as it does not significantly impair the effects of the invention according to the present embodiment. Above, it is preferably 0.5% by volume or more, more preferably 1% by volume or more, and is usually 40% by volume or less, preferably 35% by volume or less, more preferably 30% by volume or less. If the content of the sulfone-based compound is within the above range, there is a tendency to obtain an electrolytic solution with excellent high-temperature storage stability.

[1-5. Auxiliary agent]
The non-aqueous electrolytic solution of the present invention may contain various auxiliary agents as long as they do not significantly impair the effects of the present invention. As the auxiliary agent, any conventionally known one can be used. In addition, an auxiliary agent may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

Examples of auxiliary agents that may be contained in the non-aqueous electrolytic solution include cyclic carbonates having carbon-carbon unsaturated bonds, fluorine-containing cyclic carbonates, compounds having an isocyanate group, compounds having an isocyanuric acid skeleton, sulfur-containing organic compounds, Phosphorus-containing organic compounds, organic compounds having a cyano group, silicon-containing compounds, aromatic compounds, fluorine-free carboxylic acid esters, cyclic compounds having an ether bond, carboxylic acid anhydrides, borates (however, B-F bonds and /or borates having an oxalate group), oxalate salts (excluding borates having a BF bond and/or an oxalate group), and the like. Examples thereof include compounds described in International Publication No. 2015/111676.
A cyclic compound having an ether bond can also be used as an auxiliary agent in a non-aqueous electrolytic solution, and 1-4. Also included are those that can be used as non-aqueous solvents as shown in . When a cyclic compound having an ether bond is used as an auxiliary agent, it is used in an amount of less than 4% by mass. Borate and oxalate salts can also be used as auxiliary agents in non-aqueous electrolytes, and 1-3. Also included are those that can be used as electrolytes as shown in . When a borate or oxalate salt is used as an auxiliary agent, it is used at less than 3% by weight.

[2. Non-aqueous electrolyte secondary battery]
A non-aqueous electrolyte secondary battery, which is one embodiment of the present invention, comprises a positive electrode having a positive electrode active material capable of absorbing and releasing metal ions, and a negative electrode having a negative electrode active material capable of absorbing and releasing metal ions. A non-aqueous electrolyte secondary battery containing a non-aqueous electrolyte.

[2-1. Non-aqueous electrolyte]
As the non-aqueous electrolytic solution, the non-aqueous electrolytic solution described above is used. It should be noted that other non-aqueous electrolytic solutions may be mixed with the above-described non-aqueous electrolytic solution without departing from the gist of the present invention.

[2-2. negative electrode]
The negative electrode has a negative electrode active material on at least part of the current collector surface.
[2-2-1. Negative electrode active material]
The negative electrode active material used for the negative electrode is not particularly limited as long as it can electrochemically occlude and release metal ions. Specific examples include carbonaceous materials, materials containing metallic elements and/or metalloid elements that can be alloyed with Li, lithium-containing metal composite oxide materials, mixtures thereof, and the like. Among these, in terms of good cycle characteristics and safety and excellent continuous charging characteristics, carbon-based materials, materials containing metal elements and / or metalloid elements that can be alloyed with Li, or materials that can be alloyed with Li It is preferred to use a mixture of particles of a material containing metallic and/or semi-metallic elements and graphite particles. These may be used singly or in combination of two or more.

[2-2-2. carbon-based materials]
Carbon-based materials include natural graphite, artificial graphite, amorphous carbon, carbon-coated graphite, graphite-coated graphite, and resin-coated graphite. Among them, natural graphite is preferable. One type of carbon-based material may be used alone, or two or more types may be used together in any combination and ratio.
Examples of natural graphite include scale-like graphite, scale-like graphite, and/or graphite particles obtained by subjecting these to a treatment such as spheroidization or densification. Among these, spherical or ellipsoidal graphite particles subjected to a spheroidizing treatment are particularly preferable from the viewpoint of the packing properties of the particles and the charge/discharge rate characteristics.
The average particle size (d50) of graphite particles is usually 1 μm or more and 100 μm or less.

[2-2-3. Physical properties of carbonaceous materials]
The carbon-based material as the negative electrode active material preferably satisfies at least one of the physical properties, shape, and other characteristics shown in the following (1) to (4), and particularly preferably satisfies a plurality of them at the same time. .
(1) X-Ray Diffraction Parameter The d value (interlayer distance) of the lattice plane (002 plane) determined by X-ray diffraction of the carbon-based material according to the Gakushin method is usually 0.335 nm or more and 0.360 nm or less. Moreover, the crystallite size (Lc) of the carbonaceous material determined by X-ray diffraction according to the Gakushin method is usually 1.0 nm or more.
(2) Volume-Based Average Particle Size The volume-based average particle size of the carbon-based material is the volume-based average particle size (median diameter) determined by the laser diffraction/scattering method, and is usually 1 μm or more and 100 μm or less.
(3) Raman R value and Raman half-value width The Raman R value of a carbon-based material is a value measured using an argon ion laser Raman spectroscopy, and is usually 0.01 or more and 1.5 or less.
The Raman half-value width of the carbonaceous material near 1580 cm ⁻¹ is not particularly limited, but is usually 10 cm ⁻¹ or more and 100 cm ⁻¹ or less.
(4) BET Specific Surface Area The BET specific surface area of a carbon-based material is the value of the specific surface area measured using the BET method, and is usually 0.1 m ² ·g ⁻¹ or more and 100 m ² ·g ⁻¹ or less.
Moreover, two or more kinds of carbon-based materials having different properties may be contained in the negative electrode active material. The property referred to here means an X-ray diffraction parameter, volume-based average particle size, Raman R value, Raman half width or BET specific surface area.
Preferred examples include that the volume-based particle size distribution is not left-right symmetrical about the median diameter, that two or more carbonaceous materials having different Raman R values are contained, and that the carbonaceous materials having different X-ray parameters are Containing 2 or more types of materials, etc. are mentioned.

[2-2-4. Materials containing metallic elements and/or metalloid elements that can be alloyed with Li]
Any conventionally known material containing a metal element and/or metalloid element that can be alloyed with Li can be used. , As, and Zn. In addition, when a material containing a metal element and/or a metalloid element that can be alloyed with Li contains two or more types of metal elements, the material may be an alloy material made of these alloys. .
Materials containing a metal element and/or a metalloid element that can be alloyed with Li include oxides, nitrides, carbides, and the like. These may contain two or more kinds of metal elements and/or metalloid elements that can be alloyed with Li. Among them, metal Si (hereinafter sometimes referred to as Si) or Si-containing compounds are preferable from the viewpoint of increasing the capacity.

In this specification, Si or Si-containing compounds are collectively referred to as Si compounds. Specific examples of Si compounds include SiO _x , SiN _x , SiC _x , SiZ _x′ O _y (Z=C, N), and the like. As the Si compound, Si oxide (SiO _x ) is preferable in that it has a larger theoretical capacity than graphite, and amorphous Si or nano-sized Si crystals facilitate the entry and exit of alkali ions such as lithium ions. , is preferable in that it is possible to obtain a high capacity.
The Si oxide represented by the general formula SiO _x is obtained by using silicon dioxide (SiO ₂ ) and Si as raw materials, and the value of x is usually 0<x<2.
When the material containing the metal element and/or metalloid element that can be alloyed with Li is particles, the average particle diameter (d50) is usually 0.01 μm or more and 10 μm or less from the viewpoint of cycle life.

[2-2-5. A mixture of particles of a material containing a metallic element and/or semi-metallic element that can be alloyed with Li and graphite particles]
A mixture of graphite particles and particles of a material containing a metal element and/or metalloid element that can be alloyed with Li used as a negative electrode active material contains the metal element and/or metalloid element that can be alloyed with Li. It may be a mixture in which particles containing and the above-mentioned graphite particles are mixed in a state of independent particles, or particles of a material containing a metal element and / or metalloid element that can be alloyed with Li are graphite particles. It may be a complex existing on the surface or inside.
The content ratio of the particles of the material containing the metal element and/or metalloid element that can be alloyed with Li to the total of the particles of the material containing the metal element and/or metalloid element that can be alloyed with Li and the graphite particles , usually 1% by mass or more and 99% by mass or less.

[2-2-6. Lithium-containing metal composite oxide material]
The lithium-containing metal composite oxide material used as the negative electrode active material is not particularly limited as long as it can occlude and release lithium ions. A material is preferable, and a composite oxide of lithium and titanium (hereinafter sometimes abbreviated as "lithium-titanium composite oxide") is more preferable, and lithium-titanium composite oxide having a spinel structure greatly reduces the output resistance, so it is particularly preferable.

Also, lithium and/or titanium in the lithium-titanium composite oxide may be substituted with other metal elements such as at least one element selected from the group consisting of Al, Ga, Cu and Zn.
Li _4/3 Ti _5/3 O ₄ , Li ₁ Ti ₂ O ₄ and Li _4/5 Ti _11/5 O ₄ are preferable as the lithium titanium composite oxide. _Li4 / _3Ti4 / _3Al1 / _3O4 , for example, is preferable as the lithium-titanium composite oxide in which part of lithium and/or titanium is replaced with another element.

[2-2-7. Structure and manufacturing method of negative electrode]
Any known method may be used to manufacture the negative electrode as long as it does not significantly impair the effects of the present invention. For example, a binder, a solvent, and, if necessary, a binder, a solvent, a thickener, a conductive material, a filler, etc., are added to the negative electrode active material to form a slurry, which is applied to a current collector, dried, and then pressed to form a negative electrode active material. It can be made by forming a layer of material.

[2-2-7-1. current collector]
As the current collector for holding the negative electrode active material, any known current collector can be used. Examples of the current collector for the negative electrode include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel. Copper is particularly preferable in terms of ease of processing and cost.
Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, and foamed metal. Among them, a metal thin film or a metal foil is preferable. Copper foil is more preferable, and rolled copper foil obtained by a rolling method and electrolytic copper foil obtained by an electrolysis method are further preferable. Incidentally, the metal thin film and the metal foil may be appropriately formed in a mesh shape.
When the shape of the current collector of the negative electrode is plate-like, film-like, or the like, the thickness of the current collector is arbitrary, but is usually 1 μm or more and 1 mm or less.

[2-2-7-2. Binder]
The binder that binds the negative electrode active material is not particularly limited as long as it is a material that is stable with respect to the non-aqueous electrolytic solution and the solvent used in electrode production.
Specific examples include rubber-like polymers such as SBR (styrene-butadiene rubber), isoprene rubber, butadiene rubber, fluororubber, NBR (acrylonitrile-butadiene rubber), ethylene-propylene rubber; polyvinylidene fluoride, polytetrafluoroethylene, Examples thereof include fluorine-based polymers such as tetrafluoroethylene/ethylene copolymers. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.
The ratio of the binder to the negative electrode active material is usually 0.1% by mass or more and 20% by mass or less.
In particular, when a rubber-like polymer represented by SBR is contained as a main component, the ratio of the binder to the negative electrode active material is preferably 0.1% by mass or more and 5% by mass or less. Further, when the binder contains a fluorine-based polymer represented by polyvinylidene fluoride as a main component, the ratio of the binder to the negative electrode active material is preferably 1% by mass or more and 15% by mass or less. .

[2-2-7-3. solvent]
As the solvent for forming the slurry, any solvent capable of dissolving or dispersing the negative electrode active material, binder, and optionally used thickener, conductive material, filler, etc. can be used. The type of solvent is not particularly limited, and either an aqueous solvent or an organic solvent may be used.

[2-2-7-4. Thickener]
Thickeners are commonly used to adjust the viscosity of the slurry. The thickener is not particularly limited, but specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol and the like. These may be used individually by 1 type, or may use 2 or more types together by arbitrary combinations and ratios.
When a thickener is used, the ratio of the thickener to the negative electrode active material is usually 0.1% by mass or more and 5% by mass or less.

[2-2-8. Electrode density]
The electrode structure when the negative electrode active material is formed into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is usually 1 g cm ⁻³ or more and 2.2 g cm ⁻³ or less. be.

[2-2-9. Thickness of negative electrode plate]
The thickness of the negative electrode (also referred to as “negative plate”) is designed according to the positive electrode (also referred to as “positive plate”) to be used, and is not particularly limited. The thickness of the negative electrode active material layer after subtracting the thickness of is usually 15 μm or more and 300 μm or less.

[2-2-10. Surface coating of negative electrode plate]
Further, the negative electrode plate may have a surface adhered with a substance having a composition different from that of the negative electrode active material (surface adhering substance). Examples of the surface adhering substance include oxides such as aluminum oxide, sulfates such as lithium sulfate, and carbonates such as lithium carbonate.

[2-3. positive electrode]
The positive electrode has a positive electrode active material on at least part of the current collector surface.
[2-3-1. Positive electrode active material]
The positive electrode active material (lithium transition metal compound) used for the positive electrode is described below.

[2-3-1-1. Lithium transition metal compound]
A lithium transition metal compound is a compound having a structure capable of desorbing and inserting lithium ions. etc. Among them, a phosphate compound or a lithium transition metal composite oxide is preferred, and a lithium transition metal composite oxide is more preferred.
Lithium-transition metal composite oxides include those belonging to a spinel structure that enables three-dimensional diffusion and those that belong to a layered structure that enables two-dimensional diffusion of lithium ions.
Those having a spinel structure are generally represented by the following compositional formula (1).
Li _x M ₂ O ₄ (1)
(In formula (1), x is 1≤x≤1.5, and M represents one or more transition metal elements.)
Specific examples include LiMn ₂ O ₄ , LiCoMnO ₄ , LiNi _0.5 Mn _1.5 O ₄ and LiCoVO ₄ .
Those having a layered structure are generally represented by the following compositional formula (2).
Li _{x'M'O 2} (2)
(In formula (2), x' is -0.1 ≤ x' ≤ 0.5, and M' represents one or more transition metal elements.)
Specifically, LiCoO ₂ , LiNiO ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ , LiNi _0.80 Co _0.15 Al _0.05 O ₂ , LiNi _0.33 Co _0.33 Mn _{0.33O2 , Li1.05Ni0.33Co0.33Mn0.33O2 , LiNi0.5Co0.2Mn0.3O2 , Li1.05Ni0.5Co0 _ _ _ _ _ _ _ .2Mn0.3O2 , LiNi0.6Co0.2Mn0.2O2 , LiNi0.8Co0.1Mn0.1O2 and the like . _ _}

Among them, from the viewpoint of improving battery capacity, a lithium-transition metal composite oxide having a layered structure is preferable, and a lithium-transition metal composite oxide represented by the following compositional formula (3) is more preferable.
Li _a1 Ni _b1 M′ _c1 O ₂ (3)
(In formula (3), a1, b1 and c1 are numerical values satisfying 0.90 ≤ a1 ≤ 1.10, 0.30 ≤ b1 ≤ 0.98, 0.00 ≤ c1 ≤ 0.50, and b1 + c1 = 1. M' represents one or more elements selected from the group consisting of Co, Mn, Al, Mg, Zr, Fe, Ti and Er.)

In particular, a lithium-transition metal composite oxide represented by the following compositional formula (4) is preferred.
Li _a2 Ni _b2 Co _c2 M′ _d2 O ₂ (4)
(In formula (4), a2, b2, c2 and d2 are respectively 0.90 ≤ a2 ≤ 1.10, 0.33 ≤ b2 ≤ 0.98, 0.01 ≤ c2 < 0.50, 0.01 ≤ d2 < 0.50 and satisfies b2 + c2 + d2 = 1. M' represents one or more elements selected from the group consisting of Mn, Al, Mg, Zr, Fe, Ti and Er.)
In composition formula (4), d2 is preferably a numerical value that satisfies 0.10≤d2≤0.50.

Suitable specific examples of the lithium-transition metal composite oxide represented by the compositional formula (4) include LiNi _0.85 Co _0.10 Al _0.05 O ₂ and LiNi _0.80 Co _0.15 Al _{0 .05O2 , LiNi0.5Co0.2Mn0.3O2 , Li1.05Ni0.50Co0.20Mn0.30O2 , LiNi0.6Co0.2Mn0 . _ _ _ _ _ _ 2} O ₂ , LiNi _0.8 Co _0.1 Mn _0.1 O ₂ , Li _1.05 Ni _0.34 Mn _0.33 Co _0.33 O ₂ and the like.

In each composition formula, M' preferably contains Mn or Al, more preferably Mn, and even more preferably Mn or Al. This is because the structural stability of the lithium-transition metal composite oxide is enhanced, and structural deterioration during repeated charging and discharging is suppressed.

[2-3-1-2. Foreign element introduction]
Further, the lithium-transition metal composite oxide may contain an element (foreign element) other than the elements included in the above composition formula.

[2-3-1-3. surface coating]
A positive electrode active material having a different composition (surface adhering substance) attached to the surface of the positive electrode active material may be used. Examples of the surface adhering substance include oxides such as aluminum oxide, sulfates such as lithium sulfate, and carbonates such as lithium carbonate.
These surface-attaching substances can be attached to the surface of the positive electrode active material by, for example, a method of dissolving or suspending them in a solvent, impregnating and adding them to the positive electrode active material, and drying the material.
The amount of the surface-adhering substance is preferably 1 μmol/g or more, preferably 10 μmol/g or more, and usually 1 mmol/g or less, relative to the positive electrode active material.
In the present specification, a positive electrode active material having the above-described surface-attached substance attached to its surface is also referred to as a "positive electrode active material."

[2-3-1-4. blend]
In addition, these positive electrode active materials may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

[2-3-2. Configuration and Manufacturing Method of Positive Electrode]
The configuration and manufacturing method of the positive electrode will be described below. In this embodiment, the positive electrode using the positive electrode active material can be manufactured by a conventional method. That is, a positive electrode active material, a binder, and, if necessary, a conductive material, a thickening agent, and the like are dry-mixed to form a sheet, which is pressed against a positive electrode current collector, or these materials are mixed in a liquid medium. A positive electrode can be obtained by a coating method in which a positive electrode active material layer is formed on a current collector by dissolving or dispersing it in a slurry to form a slurry, applying this to a positive electrode current collector, and drying it. Further, for example, the positive electrode active material described above may be roll-molded into a sheet electrode, or may be compression-molded into a pellet electrode.
A case where the slurry is sequentially applied to the positive electrode current collector and dried will be described below.

[2-3-2-1. Active material content]
The content of the positive electrode active material in the positive electrode active material layer is usually 80% by mass or more and 98% by mass or less.

[2-3-2-2. Conductive material]
Any known conductive material can be used as the conductive material. Specific examples include metal materials such as copper and nickel; carbon-based materials such as natural graphite, graphite, and carbon black; and the like. One type of conductive material may be used alone, or two or more types may be used together in any combination and ratio. The conductive material is used so as to be contained in the positive electrode active material layer generally in an amount of 0.01% by mass or more and 50% by mass or less.

[2-3-2-3. Binder]
As the binder used for producing the positive electrode active material layer, for example, when the positive electrode active material layer is formed by a coating method, if it is a material that is dissolved or dispersed in the liquid medium for slurry, the type is Fluorinated resins such as polyvinyl fluoride, polyvinylidene fluoride, and polytetrafluoroethylene; CN groups such as polyacrylonitrile and polyvinylidene cyanide; containing polymer; and the like are preferred.
Mixtures, modified products, derivatives, random copolymers, alternating copolymers, graft copolymers, block copolymers, etc. of the above polymers can also be used. In addition, a binder may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.
When a resin is used as the binder, the weight-average molecular weight of the resin is arbitrary as long as it does not significantly impair the effects of the present invention. When the molecular weight is within this range, the strength of the electrode is improved, and the electrode can be suitably formed.
The ratio of the binder in the positive electrode active material layer is usually 0.1% by mass or more and 80% by mass or less.

[2-3-2-4. liquid medium]
As the liquid medium for forming the slurry, any solvent capable of dissolving or dispersing the positive electrode active material, the conductive material, the binder, and the thickening agent used as necessary may be used. There is no particular limitation, and either an aqueous solvent or an organic solvent may be used.

[2-3-2-5. current collector]
The material of the positive electrode 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, and tantalum. Among them, aluminum is preferred.
Examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, and foamed metal. Among these, a metal foil or a metal thin film is preferable. Incidentally, the metal foil and the metal thin film may be appropriately formed in a mesh shape.
When the shape of the current collector of the positive electrode is plate-like, film-like, or the like, the thickness of the current collector is arbitrary, but is usually 1 μm or more and 1 mm or less.

[2-3-2-6. Thickness of positive electrode plate]
The thickness of the positive electrode plate is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the positive electrode active material layer obtained by subtracting the thickness of the current collector from the thickness of the positive electrode plate is On the other hand, it is usually 10 μm or more and 500 μm or less.

[2-3-2-7. Density of positive electrode active material layer]
The positive electrode active material layer obtained by coating and drying is preferably densified by hand pressing, roller pressing, or the like in order to increase the packing density of the positive electrode active material. The density of the positive electrode active material layer present on the current collector is usually 1.5 g/cm ³ or more and 4.5 g/cm ³ or less.

[2-3-2-8. Surface coating of positive electrode plate]
In addition, the positive electrode plate may be one in which a substance having a composition different from that of the positive electrode plate is attached to the surface of the positive electrode plate. The same substances are used.

[2-4. Separator]
A separator is usually interposed between the positive electrode and the negative electrode in order to prevent a short circuit. In this case, the separator is usually impregnated with the non-aqueous electrolytic solution.

[2-4-1. material]
The material of the separator is not particularly limited as long as it is stable against a non-aqueous electrolytic solution, but is preferably, for example, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and barium sulfate. inorganic substances such as glass filters made of glass fibers; and resins such as polyolefins, more preferably polyolefins, and particularly preferably polyethylene or polypropylene. One of these materials may be used alone, or two or more of them may be used in any combination and ratio. Further, the above materials may be laminated and used.

[2-4-2. form]
The shape of the separator is not particularly limited, but thin films such as non-woven fabrics, woven fabrics and microporous films are preferably used. In the form of a thin film, one having a pore diameter of 0.01 to 1 μm and a thickness of 1 to 50 μm is preferably used. In addition to the independent thin film shape, a separator may be used in which a composite porous layer containing inorganic particles is formed on the surface of the positive electrode and/or the negative electrode using a resin binder. The form of the separator is preferably a microporous film or a non-woven fabric because of its excellent liquid retention.

[2-4-3. Porosity]
When a porous material such as a porous sheet or non-woven fabric is used as the separator, the porosity of the separator is arbitrary, but is usually 20% or more and 90% or less.

[2-4-4. air permeability]
The air permeability of the separator in the non-aqueous electrolyte secondary battery can be grasped by the Gurley value. The Gurley value indicates how difficult it is for air to pass through the film in the thickness direction, and is expressed in seconds required for 100 mL of air to pass through the film. The Gurley value of the separator is arbitrary, but usually 10-1000 seconds/100 mL.

[2-5. battery design]
[2-5-1. Electrode group]
The electrode group has a laminate structure in which the positive electrode plate and the negative electrode plate are interposed between the separators, and a structure in which the positive electrode plate and the negative electrode plate are spirally wound with the separator interposed therebetween. Either is fine. The ratio of the volume of the electrode group to the internal volume of the battery (hereinafter referred to as electrode group occupancy) is usually 40% or more and 90% or less.

[2-5-2. Current collection structure]
When the electrode group has the above-described laminated structure, a structure in which the metal core portions of the electrode layers are bundled and welded to a terminal is preferably used. A structure in which a plurality of terminals are provided in an electrode to reduce resistance is also preferably used. When the electrode group has the wound structure described above, the internal resistance can be reduced by providing a plurality of lead structures for each of the positive electrode and the negative electrode and bundling them around the terminal.

[2-5-3. Protective element]
Protective elements include PTC (Positive Temperature Coefficient) elements whose resistance increases as heat is generated by excessive current, thermal fuses, thermistors, and valves that cut off the current flowing through the circuit due to a sudden increase in battery internal pressure or internal temperature during abnormal heat generation. (current cut-off valve) or the like can be used. It is preferable to select the protective element under the condition that it does not operate under normal high-current use, and it is more preferable to design such that abnormal heat generation and thermal runaway do not occur even without the protective element.

[2-5-4. exterior body]
A non-aqueous electrolyte secondary battery is generally configured by housing the non-aqueous electrolyte, the negative electrode, the positive electrode, the separator, and the like in an exterior body (exterior case). There is no restriction on this exterior body, and any known one can be employed as long as it does not significantly impair the effects of the present invention.
The material of the exterior case is not particularly limited as long as it is stable with respect to the non-aqueous electrolytic solution used, but from the viewpoint of weight reduction, aluminum or aluminum alloy metal or laminate film is preferably used.
The exterior case using the above metals has a sealed structure by welding the metals together by laser welding, resistance welding, or ultrasonic welding, or a crimped structure using the above metals via a resin gasket. There are things to do.

[2-5-5. shape]
Moreover, the shape of the exterior case is also arbitrary, and may be cylindrical, rectangular, laminated, coin-shaped, large-sized, or the like.

Specific embodiments of the present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.
The compounds used in Examples and Comparative Examples are shown below.

[Examples 1-1 to 1-3, Comparative Examples 1-1 to 1-5]
[Preparation of non-aqueous electrolyte secondary battery]
<Preparation of non-aqueous electrolytic solution>
In a dry argon atmosphere, a mixture of ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate (volume ratio 3:4:3) was added with 1.0 mol/L (12.3% by mass of non-aqueous electrolysis) of sufficiently dried _LiPF6 . As the concentration in the liquid), the dissolved non-aqueous electrolytic solution is used as the reference electrolytic solution, and as shown in Table 1, an ester compound having a carbon-carbon unsaturated bond (indicated as “ester compound” in the table) and , combined additives were dissolved to prepare non-aqueous electrolytic solutions of Examples 1-1 to 1-3 and Comparative Examples 1-2 to 1-5. A reference electrolyte was used as the non-aqueous electrolyte in Comparative Example 1-1.

<Preparation of positive electrode>
85 parts by mass of Li _1.05 Ni _0.34 Mn _0.33 Co _0.33 O ₂ as a positive electrode active material, 10 parts by mass of acetylene black as a conductive material, and 5 parts by mass of polyvinylidene fluoride (PVdF) as a binder The parts were mixed and slurried in N-methyl-2-pyrrolidone. This was uniformly applied to an aluminum foil having a thickness of 15 μm, dried, and roll-pressed to obtain a positive electrode. The density of the positive electrode active material layer was 2.6 g/cm ³ .

<Production of negative electrode>
To 49 parts by mass of graphite powder, 50 parts by mass of an aqueous dispersion of sodium carboxymethylcellulose (concentration of sodium carboxymethylcellulose of 1% by mass) as a thickener, and an aqueous dispersion of styrene-butadiene rubber (styrene-butadiene rubber) as a binder. concentration of 49% by mass) was added and mixed with a disperser to form a slurry. The resulting slurry was uniformly applied to a copper foil having a thickness of 10 μm, dried, and roll-pressed to form a negative electrode.

<Production of non-aqueous electrolyte secondary battery>
The above positive electrode, negative electrode, and polyolefin separator were laminated in the order of negative electrode, separator, and positive electrode. The thus-obtained battery element was wrapped with an aluminum laminate film, filled with the non-aqueous electrolyte, and then vacuum-sealed to produce a sheet-like non-aqueous electrolyte secondary battery.

[Evaluation of non-aqueous electrolyte secondary battery]
The non-aqueous electrolyte secondary battery produced by the above procedure was evaluated as follows.
-Evaluation of DCR retention rate In a constant temperature bath at 25°C, a sheet-shaped non-aqueous electrolyte secondary battery is discharged at 0.025C (1C is the current value for discharging the rated capacity at a discharge capacity of 1 hour rate in 1 hour. The same applies below.), followed by constant-current/constant-voltage charging at 0.167C to a voltage of 4.2V, and then constant-current discharging at 0.167C to 2.5V.
Further, the non-aqueous electrolyte secondary battery was stabilized by storing at 60° C. for 12 hours after constant current-constant voltage charging at 0.167 C to 4.1 V. After that, constant current discharge to 2.5V was performed at 25° C., and then constant current-constant voltage charge was performed at 0.167C to a voltage of 4.2V. After that, constant current discharge to 2.5V was performed at 0.167C. Then, after constant-current-constant-voltage charging at 0.167 C to 3.7 V, constant-current discharging was performed at 0.5 C, 1.0 C, and 1.5 C for 10 seconds, and the initial DCR was obtained from the voltage and current. Next, constant current-constant voltage charging was performed at 0.2 C to a voltage of 4.2 V to complete initial charging and discharging. The non-aqueous electrolyte secondary battery after the initial charge/discharge was allowed to stand at 60° C. for 14 days. After standing for 14 days, constant current discharge to 2.5 V at 25 ° C., then constant current-constant voltage charge to 3.7 V at 0.167 C, then at 0.5 C, 1.0 C, 1.5 C A constant current discharge was performed for 10 seconds, and the DCR after storage was determined from the voltage and current. The DCR retention rate was calculated from post-storage DCR/initial DCR. Table 1 shows the results. The DCR retention rate in Table 1 is a value normalized to 100 for Comparative Example 1-1. Incidentally, it can be said that the smaller the DCR maintenance rate, the better.

From Table 1, when Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-5 are compared, ester compounds having unsaturated bonds and phosphates having PF bonds and P=O bonds in the non-aqueous electrolyte improves the DCR retention rate of the non-aqueous electrolyte secondary battery. Therefore, it can be seen that the non-aqueous electrolytic solution of the present invention can specifically improve battery performance by containing both an ester compound having an unsaturated bond and a phosphate having a PF bond and a P═O bond. Especially by combining compound 1 with a phosphate having a PF bond and a P═O bond. The reason why the suppression of the DCR increase was most remarkable is that compound 1 has a steric structure of a molecule that moderately interacts with phosphate having PF bonds and P=O bonds, so excess on the electrode It is thought that this is because the reaction can be suppressed.

[Examples 2-1 to 2-4, Comparative Examples 2-1 to 2-2]
[Preparation of non-aqueous electrolyte secondary battery]
<Preparation of non-aqueous electrolytic solution>
In a dry argon atmosphere, a mixture of ethylene carbonate, ethylmethyl carbonate and dimethyl carbonate (volume ratio 3:4:3) was added with 1.0 mol/L (12.3% by mass of non-aqueous electrolysis) of sufficiently dried _LiPF6 . As the concentration in the liquid) the dissolved non-aqueous electrolytic solution is used as a reference electrolytic solution, and as shown in Table 2, the ester compound and the combined additive are dissolved Examples 2-1 to 2-4 and Comparative Examples Non-aqueous electrolytic solutions 2-1 and 2-2 were prepared.

<Preparation of positive electrode>
Positive electrodes were prepared and used in the same manner as in Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-5.

<Production of negative electrode>
Negative electrodes were prepared and used in the same manner as in Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-5.

<Production of non-aqueous electrolyte secondary battery>
The above positive electrode, negative electrode, and polyolefin separator were laminated in the order of negative electrode, separator, and positive electrode. The thus-obtained battery element was wrapped with an aluminum laminate film, filled with the non-aqueous electrolyte, and then vacuum-sealed to produce a sheet-like non-aqueous electrolyte secondary battery.

[Evaluation of non-aqueous electrolyte secondary battery]
Non-aqueous electrolyte secondary batteries produced in Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-2 are Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-5. performed the same evaluation. Table 2 shows the results. The DCR retention rate in Table 2 is a value normalized to 100 for Comparative Example 1-1.

From Table 1, the co-addition of compound 1 and a phosphate having a PF bond and a P=O bond significantly improved the battery characteristics. It was investigated. From the comparison between Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-2, it can be seen that the increase in DCR can be specifically suppressed by simultaneously containing a specific combined additive.
These results show that the non-aqueous electrolytic solution of the present invention can specifically improve battery performance by containing an ester compound having a carbon-carbon unsaturated bond and a specific combined additive.

Claims (7)

A compound (A) represented by formula (I), a phosphate having a PF bond and a P=O bond, a sulfonate having an SF bond, and a BF bond and/or an oxalate group and one or more compounds (B) selected from the group consisting of borate salts.

(In Formula (I), R ¹ to R ⁶ are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group, and R ¹ and R ² , R ¹ and R ³ , R ⁴ and R ⁵ , and R ⁵ and R ⁶ may combine with each other to form a cyclic structure, and n is an integer of 0 to 4.) In the above formula (I), R ¹ to R ⁶ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, and an aryl group having 6 to 12 carbon atoms. , or an aralkyl group having 7 to 18 carbon atoms, the non-aqueous electrolytic solution according to claim 1. According to claim 1 or 2, wherein the compound (A) represented by the formula (I) is a vinyl ester compound represented by the following formula (II) and/or an allyl ester compound represented by the formula (III) The non-aqueous electrolyte described.

(In Formula (II), R ⁷ to R ⁹ are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group, and R ⁷ and R ⁸ and R ⁷ and R ⁹ are bonded to each other to form a cyclic structure. may be.)

(In Formula (III), R ¹⁰ to R ¹² are each independently a hydrogen atom, a halogen atom, or a hydrocarbon group, and R ¹⁰ and R ¹¹ and R ¹⁰ and R ¹² are bonded to each other to form a cyclic structure. may be.) The non-aqueous electrolytic solution according to any one of claims 1 to 3, wherein the compound (A) represented by formula (I) is allyl methacrylate. The non-aqueous electrolytic solution according to any one of claims 1 to 4, containing 0.01% by mass or more and 10% by mass or less of the compound (A) represented by the formula (I). 1 selected from the group consisting of a phosphate having a PF bond and a P=O bond, a sulfonate having an SF bond, a borate having a BF bond and a borate having an oxalate group The non-aqueous electrolytic solution according to any one of claims 1 to 5, containing 0.01% by mass or more and 10% by mass or less of the compound (B) of at least one species. A positive electrode having a positive electrode active material capable of absorbing and releasing metal ions, a negative electrode having a negative electrode active material capable of absorbing and releasing metal ions, and the non-aqueous electrolytic solution according to any one of claims 1 to 6. A non-aqueous electrolyte secondary battery comprising: