JP2021096913A - Nonaqueous electrolyte for battery and lithium-ion secondary battery - Google Patents

Abstract

To provide a nonaqueous electrolyte for a battery that can reduce the battery resistance after storage.SOLUTION: The nonaqueous electrolyte for a battery includes an electrolyte containing lithium hexafluorophosphate, an additive A, which is at least one type selected from the group consisting of compounds represented by (A1), an additive B, which is vinylene carbonate, and an additive C, which is at least one type selected from the group consisting of a compound represented by the following general formula (C1) and a similar compound (C2). In formula (C1), Rc11 to Rc14 independently represent H, a hydrocarbon group of C number 1 to 6, a group represented by formula (a), or a group represented by formula (b).SELECTED DRAWING: None

Description

The present disclosure relates to a non-aqueous electrolyte solution for a battery and a lithium ion secondary battery.

In recent years, lithium-ion secondary batteries have been widely used as power sources for electronic devices such as mobile phones and notebook computers, electric vehicles, and power storage. In particular, recently, there has been a rapid increase in demand for batteries with high capacity, high output, and high energy density that can be installed in hybrid vehicles and electric vehicles.
The lithium ion secondary battery includes, for example, a positive electrode and a negative electrode containing a material capable of occluding and releasing lithium, and a non-aqueous electrolyte solution for a battery containing a lithium salt and a non-aqueous solvent.
As the positive electrode active material used for the positive electrode, for example, lithium metal oxides such as _{LiCoO 2} , LiMnO ₂ , LiNiO ₂ , and LiFePO _{4 are used.
The non-aqueous electrolyte solution for batteries includes LiPF 6} , LiBF ₄ , and LiN (SO ₂ CF ₃ ) in a mixed solvent (non-aqueous solvent) of carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. _2. A solution mixed with a Li electrolyte such as LiN (SO ₂ CF ₂ CF ₃ ) _{2 is used.}
On the other hand, as active materials for negative electrodes used for negative electrodes, metallic lithium, metal compounds capable of occluding and releasing lithium (single metal, oxides, alloys with lithium, etc.) and carbon materials are known, and in particular, lithium is used. Lithium-ion secondary batteries using coke, artificial graphite, and natural graphite that can be occluded and released have been put into practical use.

In order to improve the performance of a battery (for example, a lithium ion secondary battery) containing a non-aqueous electrolyte solution for a battery, various additives are added to the non-aqueous electrolyte solution for a battery.
As a non-aqueous electrolyte solution for batteries capable of improving the charge / discharge characteristics and life characteristics of a battery, a non-aqueous electrolyte solution for batteries containing a sulton compound having a specific structure is known (see, for example, Patent Document 1 below). ..
Further, as a non-aqueous electrolyte solution for a battery that can improve the capacity maintenance performance of the battery and suppress a decrease in the open circuit voltage when the battery is charged and stored, the non-aqueous electrolysis solution for a battery containing a cyclic sulfate ester compound having a specific structure. Liquids are known (see, for example, Patent Document 2 below).

Japanese Unexamined Patent Publication No. 2004-087437 International Publication No. 2012/053644

However, there are cases where it is required to further reduce the battery resistance after storage with respect to the conventional non-aqueous electrolyte solution for batteries and batteries.
Therefore, an object of the present disclosure is to provide a non-aqueous electrolyte solution for a battery capable of reducing battery resistance after storage, and a lithium ion secondary battery using this non-aqueous electrolyte solution for a battery.

<1>
An electrolyte containing lithium hexafluorophosphate, an additive A which is at least one selected from the group consisting of a compound represented by the following formula (A1), an additive B which is a vinylene carbonate, and the following formula (C1). ), And at least one additive C selected from the group consisting of the compound represented by the following formula (C2).
A non-aqueous electrolyte solution for batteries containing.

〔式（Ａ１）中、Ｒ^ａ１は、水素原子、フッ素原子、炭素数１〜６の炭化水素基、炭素数１〜６の炭化水素オキシ基、又は炭素数１〜６のフッ化炭化水素基を表す。
式（Ｃ１）中、Ｒ^ｃ１１〜Ｒ^ｃ１４は、それぞれ独立に、水素原子、炭素数１〜６の炭化水素基、式（ａ）で表される基、又は式（ｂ）で表される基を表す。式（ａ）及び式（ｂ）において、＊は、結合位置を表す。
式（Ｃ２）中、Ｒ^ｃ２１〜Ｒ^ｃ２４は、それぞれ独立に、水素原子、フッ素原子、炭素数１〜３の炭化水素基、又は炭素数１〜３のフッ化炭化水素基を表す。〕
＜２＞
前記添加剤Ａの含有量が、非水電解液の全量に対し、０．１質量％以上２．０質量％以下である＜１＞に記載の電池用非水電解液。
＜３＞
前記添加剤Ｂの含有量が、非水電解液の全量に対し、０．１質量％以上２．０質量％以下である＜１＞又は＜２＞に記載の電池用非水電解液。
＜４＞
前記添加剤Ｃの含有量が、非水電解液の全量に対し、０．１質量％以上２．０質量％以下である＜１＞〜＜３＞のいずれか１つに記載の電池用非水電解液。
＜５＞
前記電解質の濃度は、非水電解液の全量に対し、０．１ｍｏｌ／Ｌ以上３ｍｏｌ／Ｌ以下である＜１＞〜＜４＞のいずれか１つに記載の電池用非水電解液。
＜６＞
正極活物質を含有する正極活物質層を含む正極と、
負極活物質を含有する負極活物質層を含む負極と、
＜１＞〜＜５＞のいずれか１つに記載の電池用非水電解液と、
を備えるリチウムイオン二次電池。
＜７＞
前記正極活物質はリチウムニッケルマンガンコバルト複合酸化物を含む＜６＞に記載のリチウムイオン二次電池。
＜８＞
前記負極活物質は炭素材料を含む＜６＞又は＜７＞に記載のリチウムイオン二次電池。
＜９＞
＜６＞〜＜８＞のいずれか一項に記載のリチウムイオン二次電池を充放電させて得られたリチウムイオン二次電池。

[In the formula (A1), ^Ra1 is a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbon oxy group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms. Represents.
In the formula (C1), R ^{c11 to} R ^c14 are independently each of a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by the formula (a), or a group represented by the formula (b). Represents. In formulas (a) and (b), * represents a coupling position.
In the formula (C2), R ^{c21 to} R ^c24 independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms. ]
<2>
The non-aqueous electrolytic solution for a battery according to <1>, wherein the content of the additive A is 0.1% by mass or more and 2.0% by mass or less with respect to the total amount of the non-aqueous electrolytic solution.
<3>
The non-aqueous electrolytic solution for a battery according to <1> or <2>, wherein the content of the additive B is 0.1% by mass or more and 2.0% by mass or less with respect to the total amount of the non-aqueous electrolytic solution.
<4>
The non-battery for battery according to any one of <1> to <3>, wherein the content of the additive C is 0.1% by mass or more and 2.0% by mass or less with respect to the total amount of the non-aqueous electrolytic solution. Water electrolyte.
<5>
The non-aqueous electrolyte solution for a battery according to any one of <1> to <4>, wherein the concentration of the electrolyte is 0.1 mol / L or more and 3 mol / L or less with respect to the total amount of the non-aqueous electrolyte solution.
<6>
A positive electrode containing a positive electrode active material layer containing a positive electrode active material, and a positive electrode
A negative electrode containing a negative electrode active material layer containing a negative electrode active material, and a negative electrode
The non-aqueous electrolyte solution for batteries according to any one of <1> to <5>.
Lithium-ion secondary battery with.
<7>
The lithium ion secondary battery according to <6>, wherein the positive electrode active material contains a lithium nickel manganese cobalt composite oxide.
<8>
The lithium ion secondary battery according to <6> or <7>, wherein the negative electrode active material contains a carbon material.
<9>
A lithium ion secondary battery obtained by charging / discharging the lithium ion secondary battery according to any one of <6> to <8>.

According to the present disclosure, a non-aqueous electrolyte solution for a battery capable of reducing battery resistance after storage, and a lithium ion secondary battery using this non-aqueous electrolyte solution for a battery are provided.

It is a schematic perspective view which shows an example of the laminated type battery which is an example of the lithium ion secondary battery of this disclosure. It is schematic cross-sectional view in the thickness direction of the laminated type electrode body housed in the laminated type battery shown in FIG. It is the schematic cross-sectional view which shows the example of the coin type battery which is another example of the lithium ion secondary battery of this disclosure.

In the present specification, the numerical range represented by using "~" means a range including the numerical values before and after "~" as the lower limit value and the upper limit value.
In the present specification, the amount of each component in the composition is the total amount of the plurality of substances present in the composition unless otherwise specified, when a plurality of substances corresponding to each component are present in the composition. Means.

[Non-aqueous electrolyte for batteries]
The non-aqueous electrolyte solution for batteries (hereinafter, also simply referred to as “non-aqueous electrolyte solution”) of the present disclosure is selected from the group consisting of an electrolyte containing lithium hexafluorophosphate and a compound represented by the following formula (A1). At least selected from the group consisting of at least one additive A, additive B which is a vinylene carbonate, a compound represented by the following formula (C1), and a compound represented by the following formula (C2). It contains one kind of additive C and.
According to the non-aqueous electrolyte solution of the present disclosure, the battery resistance of the battery after storage can be reduced.
The reason for this effect is not clear, but it is presumed as follows.
The non-aqueous electrolytic solution of the present disclosure contains Additives A to C, and it is considered that the battery characteristics after storage can be improved by combining these additives.

<Additive A>
Additive A is at least one selected from the group consisting of compounds represented by the following formula (A1).

In the formula (A1), ^Ra1 contains a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbon oxy group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms. Represent.

The "hydrocarbon group having 1 to 6 carbon atoms" represented by ^{Ra 1 represents an unsubstituted hydrocarbon group having 1 to 6 carbon atoms.}
The ^{"hydrocarbon group having 1 to 6 carbon atoms" represented by Ra1} may be a linear hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group.
As "hydrocarbon group having 1 to 6 carbon atoms" represented by R ^a1 is an alkyl group, an alkenyl group, or a phenyl group, more preferably an alkyl group or an alkenyl group, an alkyl group is more preferable.
Carbon number of represented by R ^a1 "hydrocarbon group having 1 to 6 carbon atoms", 1-3, more preferably 1 or 2, 1 is particularly preferred.

Examples of the "hydrocarbon group having 1 to 6 carbon atoms" represented by R ^a1 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, and the like. Alkyl groups such as pentyl group, 2-methylbutyl group, 1-methylpentyl group, neopentyl group, 1-ethylpropyl group, hexyl group, 3,3-dimethylbutyl group; vinyl group, 1-propenyl group, allyl group, 1 -Butenyl group, 2-butenyl group, 3-butenyl group, pentenyl group, hexenyl group, isopropenyl group, 2-methyl-2-propenyl group, 1-methyl-2-propenyl group, 2-methyl-1-propenyl group Etc., such as an alkenyl group;

Specific examples and preferred embodiments of the "hydrocarbon group having 1 to 6 carbon atoms" in the structure of the "hydrocarbon group having 1 to 6 carbon atoms" represented by R ^a1 may previously described, represented by R ^a1 This is the same as the specific example and the preferred embodiment of the “hydrocarbon group having 1 to 6 carbon atoms”.

Specific examples and preferred embodiments of the "fluorinated hydrocarbon group having 1 to 6 carbon atoms" represented by R ^a1 are described above in the above-mentioned "table having 1 to 6 carbon atoms" represented by ^{Ra 1 in the formula (A1).} This is the same as the preferred embodiment of the "hydrocarbon group".

Wherein ^(A1), as the ^{R a1,} hydrocarbon group having 1 to 6 carbon atoms (i.e., unsubstituted hydrocarbon group having 1 to 6 carbon atoms), and particularly preferably an alkyl group having 1 to 6 carbon atoms ..

The compound represented by the formula (A1) includes
Methansulfonyl fluoride, ethanesulfonyl fluoride, propanesulfonyl fluoride, 2-propanesulfonyl fluoride, butane sulfonyl fluoride, 2-butane sulfonyl fluoride, hexanesulfonyl fluoride, trifluoromethanesulfonyl fluoride, perfluoroethanesulfonyl fluoride Do, perfluoropropanesulfonyl fluoride, perfluorobutane sulfonyl fluoride, ethensulfonyl fluoride, 1-propen-1-sulfonyl fluoride, or 2-propen-1-sulfonyl fluoride is preferred.
Methanesulfonyl fluoride, ethanesulfonyl fluoride, propanesulfonyl fluoride, 2-propanesulfonyl fluoride, butane sulfonyl fluoride, 2-butane sulfonyl fluoride, hexanesulfonyl fluoride, trifluoromethanesulfonyl fluoride, perfluoroethanesulfonyl fluoride Do, perfluoropropanesulfonyl fluoride, or perfluorobutanesulfonyl fluoride is more preferred.
Methanesulfonyl fluoride, ethanesulfonyl fluoride, propanesulfonyl fluoride, 2-propanesulfonyl fluoride, butane sulfonyl fluoride, 2-butane sulfonyl fluoride, or hexanesulfonyl fluoride are more preferred.
Methanesulfonyl fluoride, ethanesulfonyl fluoride, or propanesulfonyl fluoride are more preferred.
Methanesulfonyl fluoride is particularly preferred.

The content of the additive A is preferably 0.01% by mass to 5% by mass, more preferably 0.05% by mass to 3% by mass, and further preferably 0, based on the total amount of the non-aqueous electrolyte solution. .1% by mass to 2% by mass, more preferably 0.1% by mass to 1% by mass.

<Additive B>
Additive B is vinylene carbonate (hereinafter, also referred to as “VC”).

The content of the additive B is preferably 0.01% by mass to 5% by mass, more preferably 0.05% by mass to 3% by mass, and further preferably 0, based on the total amount of the non-aqueous electrolyte solution. .1% by mass to 2% by mass, more preferably 0.1% by mass to 1% by mass.

<Additive C>
The additive C is at least one selected from the group consisting of the compound represented by the following formula (C1) and the compound represented by the following formula (C2).

The compound represented by the formula (C1) is as follows.

In the formula (C1), R ^{c11 to} R ^c14 are independently each of a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by the formula (a), or a group represented by the formula (b). Represents. In formulas (a) and (b), * represents a coupling position.

In the formula (C1), ^{the hydrocarbon group having 1 to 6 carbon atoms represented by R c11 to} R ^c14 is preferably an alkyl group, an alkenyl group, or an alkynyl group, more preferably an alkyl group or an alkenyl group, and an alkyl group. Is particularly preferable.
In the formula (C1), the number of carbon atoms of the hydrocarbon groups having 1 to 6 carbon atoms represented by ^{R c11 to} R ^{c14 is preferably 1 or 2, and particularly preferably 1.}

Specific examples of the compound represented by the formula (C1) include compounds represented by the following formulas (C1-1) to (C1-4) (hereinafter, compounds (C1-1) to compounds (C1), respectively). -4)), but the compound represented by the formula (C1) is not limited to these specific examples.
Of these, compounds (C1-1) to compounds (C1-3) are particularly preferable.

The compound represented by the formula (C2) is as follows.

In the formula (C2), R ^{c21 to} R ^c24 independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms.

In the formula (C2), R ^{c21 to} R ^c24 independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms.

In the formula (C2), ^{the hydrocarbon group having 1 to 3 carbon atoms represented by R c21 to} R ^c24 may be a linear hydrocarbon group, or a hydrocarbon group having a branched and / or ring structure. It may be.
As ^{the hydrocarbon group having 1 to 3 carbon atoms represented by R c21 to} R ^c24 , an alkyl group or an aryl group is preferable, and an alkyl group is more preferable.
The number of carbon atoms of the hydrocarbon group having 1 to 3 carbon atoms represented by ^{R c21 to} R ^{c24 is preferably 1 or 2, and more preferably 1.}

In the formula (C2), ^{the fluorinated hydrocarbon group having 1 to 3 carbon atoms represented by R c21 to} R ^c24 may be a linear fluorinated hydrocarbon group, and may have a branched and / or ring structure. It may be a fluorinated hydrocarbon group having.
As ^{the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by R c21 to} R ^c24 , an alkyl fluorinated group or an aryl fluorinated group is preferable, and an alkyl fluorinated group is more preferable.
The number of carbon atoms of the fluorinated hydrocarbon group having 1 to 3 carbon atoms represented by ^{R c21 to} R ^{c24 is preferably 1 or 2, and more preferably 1.}

Specific examples of the compound represented by the formula (C2) include compounds represented by the following formulas (C2-1) to (C2-21) (hereinafter, compounds (C2-1) to compound (C2, respectively). -21)), but the compound represented by the formula (C2) is not limited to these specific examples.
Of these, compound (C2-1) is particularly preferable.

The content of the additive C is preferably 0.01% by mass to 5% by mass, more preferably 0.05% by mass to 3% by mass, and further preferably 0, based on the total amount of the non-aqueous electrolyte solution. .1% by mass to 2% by mass, more preferably 0.1% by mass to 1% by mass.

The non-aqueous electrolytic solution of the present disclosure may contain at least one of Additives D to H, which will be described later.

<Additive D>
The non-aqueous electrolytic solution of the present disclosure may contain an additive D, which is at least one selected from the group consisting of the compounds represented by the formula (D1).

In the formula (D1), R ^{d11 to} R ^d14 independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms.

In the formula (D1), ^{the hydrocarbon group having 1 to 6 carbon atoms represented by R d11 to} R ^d14 may be a linear hydrocarbon group, or a hydrocarbon group having a branched and / or ring structure. It may be.
As ^{the hydrocarbon group having 1 to 6 carbon atoms represented by R d11 to} R ^d14 , an alkyl group or an aryl group is preferable, and an alkyl group is more preferable.

In the formula (D1), ^{as the carbon number of the hydrocarbon group having 1 to 6 carbon atoms represented by R d11 to} R ^d14 , 1 to 3 is more preferable, 1 or 2 is further preferable, and 1 is particularly preferable.

In the formula (D1), ^{the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by R d11 to} R ^d14 may be a linear fluorinated hydrocarbon group, and may have a branched and / or ring structure. It may be a fluorinated hydrocarbon group having.
As ^{the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by R d11 to} R ^d14 , an alkyl fluorinated group or an aryl fluorinated group is preferable, and an alkyl fluorinated group is more preferable.

In the formula (D1), the ^{number of carbon atoms of the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by R d11 to} R ^d14 is more preferably 1 to 3, further preferably 1 or 2, and particularly preferably 1. ..

Specific examples of the compound represented by the formula (D1) include compounds represented by the following formulas (D1-1) to (D1-9) (hereinafter, compounds (D1-1) to compounds (D1), respectively). -9)), but the compound represented by the formula (D1) is not limited to these specific examples.
Of these, compound (D1-1) or compound (D1-2) is particularly preferable.

When the non-aqueous electrolytic solution of the present disclosure contains the additive D, the content of the additive D with respect to the total amount of the non-aqueous electrolytic solution is preferably 0.001% by mass to 10% by mass, preferably 0.005% by mass or more. 5% by mass is more preferable, 0.01% by mass to 2% by mass is further preferable, and 0.1% by mass to 1% by mass is particularly preferable.

<Additive E>
The non-aqueous electrolytic solution of the present disclosure may contain an additive E which is at least one selected from the group consisting of compounds represented by the following formula (E1).

In the formula (E1), R ^{e11 to} R ^e14 independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms. However, ^{Re11 to Re14} do not become hydrogen atoms at the same time.

In the formula (E1), a preferred embodiment of the hydrocarbon group having 1 to 6 carbon atoms represented by ^{R e11 to} R ^e14 is a hydrocarbon group having 1 to 6 carbon atoms represented by ^{R d11 to} R ^{d14 in the formula (D1).} Similar to the hydrocarbon group.
However, it is also preferable that the hydrocarbon group having 1 to 6 carbon atoms represented by ^{Re 11 to Re 14 is an alkenyl group.}
The ^{number of carbon atoms of the hydrocarbon group having 1 to 6 carbon atoms represented by Re 11} to Re 14 is preferably 1 to 3, more preferably 1 or 2, and particularly preferably 1.

In the formula (E1), a preferred embodiment of the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by ^{R e11 to} R ^{e14 is a preferred embodiment having 1 to 6 carbon atoms represented by R d11 to} R ^d14 in the formula (D1). This is the same as the preferred embodiment of the fluorinated hydrocarbon group of 6.
However, it is also preferable that the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by ^{R e11 to} R ^{e14 is a fluorinated alkenyl group.}
The number of carbon atoms of the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by R ^{e11 to Re 14 is preferably 1 to 3, more preferably 1 or 2, and particularly preferably 1.}

Specific examples of the compound represented by the formula (E1) include compounds represented by the following formulas (E1-1) to (E1-5) (hereinafter, compounds (E1-1) to compound (E1), respectively. -5)), but the compound represented by the formula (E1) is not limited to these specific examples.
Of these, compound (E1-1) or compound (E1-2) is particularly preferable.

When the non-aqueous electrolyte solution of the present disclosure contains the additive E, the content of the additive E with respect to the total amount of the non-aqueous electrolyte solution is preferably 0.001% by mass to 10% by mass, preferably 0.005% by mass or more. 5% by mass is more preferable, 0.01% by mass to 2% by mass is further preferable, and 0.1% by mass to 1% by mass is particularly preferable.

<Additive F>
The non-aqueous electrolytic solution of the present disclosure may contain an additive F which is at least one selected from the group consisting of compounds represented by the following formula (F1).

Wherein ^{(F1), R} f11 ~R ^f13 each independently represents a fluorine atom or -OLi ^group, at least one of -OLi group R f11 ^{to R f13.}

Specific examples of the compound represented by the formula (F1) include the compound represented by the following formula (F1-1) and the following formula (F1-2) (hereinafter, the compound (F1-1) and the compound (F1), respectively). -2)), but the compound represented by the formula (F1) is not limited to these specific examples.

When the non-aqueous electrolytic solution of the present disclosure contains the additive F, the content of the additive F with respect to the total amount of the non-aqueous electrolytic solution is preferably 0.001% by mass to 10% by mass, preferably 0.005% by mass or more. 5% by mass is more preferable, 0.01% by mass to 2% by mass is further preferable, and 0.1% by mass to 1% by mass is particularly preferable.

<Additive G>
The non-aqueous electrolytic solution of the present disclosure may contain an additive G which is at least one selected from the group consisting of compounds represented by the following formula (G1).

In the formula (G1), R ^{g11 to} R ^g16 independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms.

In the formula (G1), ^{a preferred embodiment of the hydrocarbon group having 1 to 3 carbon atoms represented by R g11 to} R ^{g16 is R d11 in the} formula (D1) except that the hydrocarbon group has 1 to 3 carbon atoms. This is the same as the preferred embodiment of the hydrocarbon group having 1 to 6 carbon atoms represented by ~ R ^d14.
The number of carbon atoms of the hydrocarbon group having 1 to 3 carbon atoms represented by ^{R g11 to} R ^{g16 is preferably 1 or 2, and more preferably 1.}

In the formula (G1), ^{a preferred embodiment of the fluorinated hydrocarbon group having 1 to 3 carbon atoms represented by R g11 to} R ^g16 is in the formula (D1) except that the number of carbon atoms is 1 to 3. This is the same as the preferred embodiment of the fluorinated hydrocarbon group having 1 to 6 carbon atoms represented by ^{R d11 to} R ^d14.
The number of carbon atoms of the fluorinated hydrocarbon group having 1 to 3 carbon atoms represented by ^{R g11 to} R ^{g16 is preferably 1 or 2, and more preferably 1.}

Specific examples of the compound represented by the formula (G1) include compounds represented by the following formulas (G1-1) to (G1-21) (hereinafter, compounds (G1-1) to compounds (G1), respectively). -21)), but the compound represented by the formula (G1) is not limited to these specific examples.
Of these, compound (G1-1) is particularly preferable.

When the non-aqueous electrolyte solution of the present disclosure contains the additive G, the content of the additive G with respect to the total amount of the non-aqueous electrolyte solution is preferably 0.001% by mass to 10% by mass, preferably 0.005% by mass or more. 5% by mass is more preferable, 0.01% by mass to 2% by mass is further preferable, and 0.1% by mass to 1% by mass is particularly preferable.

<Additive H>
The non-aqueous electrolytic solution of the present disclosure may contain an additive H which is at least one selected from the group consisting of compounds represented by the following formula (H1).

In the formula (H1), M represents an alkali metal, Y represents a transition element or a group 13, 14 or 15 element of the periodic table, b is an integer of 1 to 3, and m is 1 to 4. , N is an integer from 0 to 8, and q is 0 or 1. R ^h11 is an alkylene group having 1 to 10 carbon atoms, an alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or an arylene halide group having 6 to 20 carbon atoms (these groups are: The structure may contain a substituent or a heteroatom, and when q is 1 and m is 2 to 4, m R ^h11 may be bonded to each other). ^h12 is a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkyl halide group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aryl halide group having 6 to 20 carbon atoms (these groups are , A substituent or a heteroatom may be contained in the structure, and when n is 2 to 8, n R ^h12s may be bonded to each other to form a ring), or. -X ³ Represents R ^h13. X ¹ , X ² and X ³ independently represent O, S or NR ^h14 , and R ^h13 and R ^h14 independently represent a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and 1 to 10 carbon atoms, respectively. An alkyl halide group of 10 or an aryl group having 6 to 20 carbon atoms or an aryl halide group having 6 to 20 carbon atoms (these groups may contain a substituent or a hetero atom in the structure, and may contain R. ^{When a} plurality of h13 or R ^h14 are present, they may be combined to form a ring).

In formula (H1), M is an alkali metal and Y is a transition metal or a Group 13, 14 or 15 element of the periodic table. Of these, Y is preferably Al, B, V, Ti, Si, Zr, Ge, Sn, Cu, Y, Zn, Ga, Nb, Ta, Bi, P, As, Sc, Hf or Sb. , Al, B or P is more preferred. When Y is Al, B or P, the synthesis of the anionic compound becomes relatively easy, and the production cost can be suppressed. B, which represents the valence of anions and the number of cations, is an integer of 1 to 3, preferably 1. When b is larger than 3, the salt of the anionic compound tends to be difficult to dissolve in the mixed organic solvent, which is not preferable. Further, the constants m and n are values related to the number of ligands and are determined by the type of M, but m is an integer of 1 to 4 and n is an integer of 0 to 8. The constant q is 0 or 1. When q is 0, the chelate ring is a 5-membered ring, and when q is 1, the chelate ring is a 6-membered ring.

R ^h11 represents an alkylene group having 1 to 10 carbon atoms, a halogenated alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a halogenated arylene group having 6 to 20 carbon atoms. These alkylene group, halogenated alkylene group, arylene group or halogenated arylene group may contain a substituent and a hetero atom in the structure. Specifically, instead of the hydrogen atom of these groups, a halogen atom, a chain or cyclic alkyl group, an aryl group, an alkenyl group, an alkoxy group, an aryloxy group, a sulfonyl group, an amino group, a cyano group, a carbonyl group, It may contain an acyl group, an amide group, or a hydroxyl group as a substituent. Further, the structure may have a structure in which a nitrogen atom, a sulfur atom, or an oxygen atom is introduced instead of the carbon element of these groups. Further, when q is 1 and m is 2 to 4, m R ^h11s may be bonded to each other. Such examples include ligands such as ethylenediaminetetraacetic acid.

R ^h12 is a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, a halogenated aryl group, or -X ³ of 6 to 20 carbon atoms R ^{h13 (X 3,} the ^{R h13} is described later.) represents the.
These alkyl groups in R ^h12, halogenated alkyl group, an aryl group or a halogenated aryl group, like R ^h11, substituent in the structure may contain a hetero atom, also, n is 2 When it is 8, n R ^12s may be combined to form a ring. As R ⁹² , an electron-withdrawing group is preferable, and a fluorine atom is particularly preferable.

X ¹ , X ² and X ³ independently represent O, S or NR ^h14 , respectively. That is, the ligand will bond to Y via these heteroatoms.

R ^h13 and R ^h14 independently have a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an alkyl halide group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a carbon collection 6 to 20. Represents an aryl halide group. These alkyl groups, alkyl halide groups, aryl groups, or aryl halide groups may contain a substituent or a hetero atom in the structure thereof, similarly to ^{R h11.} When a ^{plurality of R h13} and R ^h14 are present, they may be combined to form a ring.

Examples of the alkali metal represented by M include lithium, sodium, potassium and the like. Of these, lithium is particularly preferable.
As n, an integer of 0 to 4 is preferable.

Examples of the compound represented by the formula (H1) include a compound represented by the following formula (H1-1), a compound represented by the following formula (H1-2), and a compound represented by the following formula (H1-3). , At least one selected from the group consisting of the compound represented by the following formula (H1-4) and the compound represented by the following formula (H1-5) is more preferable.

In formulas (H1-1) to (H1-5), M is synonymous with M in formula (H1), and the preferred embodiment is also the same.

The compound represented by the formula (H1) is particularly preferably a compound represented by the formula (H1-1) in which M is lithium, or a compound represented by the formula (H1-4). It is a compound in which M is lithium.

When the non-aqueous electrolytic solution of the present disclosure contains the additive H, the content of the additive H with respect to the total amount of the non-aqueous electrolytic solution is preferably 0.001% by mass to 10% by mass, preferably 0.005% by mass or more. 5% by mass is more preferable, 0.01% by mass to 2% by mass is further preferable, and 0.1% by mass to 1% by mass is particularly preferable.

<Electrolyte>
The non-aqueous electrolyte solution of the present disclosure contains an electrolyte containing _{lithium hexafluorophosphate (also referred to as "LiPF 6").}
The ratio of LiPF _{6 in} the electrolyte is preferably 10% by mass to 100% by mass, more preferably 50% by mass to 100% by mass, and further preferably 70% by mass to 100% by mass.

The concentration of the electrolyte in the non-aqueous electrolyte solution of the present disclosure is preferably 0.1 mol / L to 3 mol / L, more preferably 0.5 mol / L to 2 mol / L.
_{The concentration of LiPF 6} in the non-aqueous electrolytic solution of the present disclosure is preferably 0.1 mol / L to 3 mol / L, more preferably 0.5 mol / L to 2 mol / L.

The electrolyte may contain a compound other than _{LiPF 6.}
As a compound other than _{LiPF 6,;}
(C ₂ H ₅ ) ₄ NPF ₆ , (C ₂ H ₅ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NClo ₄ , (C ₂ H ₅ ) ₄ NAsF ₆ , (C ₂ H ₅ ) ₄ N ₂ SiF ₆ , (C ₂ H ₅ ) ₄ NOSO ₂ C _k F _{(2 k + 1)} (integer of k = 1 to 8), (C ₂ H ₅ ) ₄ NPF _n [C _k F _{(2 k + 1)} ] _(6-n) ( Tetraalkylammonium salts such as n = 1 to 5 integers, k = 1 to 8 integers);
LiBF ₄ , LiClO ₄ , LiAsF ₆ , Li ₂ SiF ₆ , LiOSO ₂ C _k F _{(2 k + 1)} (integer of k = 1 to 8), LiPF _n [C _k F _{(2 k + 1)} ] _(6-n) (n = Integers 1 to 5, k = integers 1 to 8), LiC (SO ₂ R ⁷ ) (SO ₂ R ⁸ ) (SO ₂ R ⁹ ), LiN (SO ₂ OR ¹⁰ ) (SO ₂ OR ¹¹ ), LiN Lithium salts such as (SO ₂ R ¹² ) (SO ₂ R ¹³ ) (where R ^{7 to} R ¹³ may be the same or different from each other and are fluorine atoms or perfluoroalkyl groups having 1 to 8 carbon atoms). (That is, lithium salts other than _{LiPF 6);}
And so on.

<Non-aqueous solvent>
The non-aqueous electrolyte solution of the present disclosure may contain a non-aqueous solvent.
The non-aqueous solvent may be only one kind or two or more kinds.
As the non-aqueous solvent, various known solvents can be appropriately selected.
As the non-aqueous solvent, for example, the non-aqueous solvent described in paragraphs 0069 to 0087 of JP-A-2017-45723 can be used.

The non-aqueous solvent preferably contains a cyclic carbonate compound and a chain carbonate compound.
In this case, the cyclic carbonate compound and the chain carbonate compound contained in the non-aqueous solvent may be only one kind or two or more kinds, respectively.

Examples of the cyclic carbonate compound include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, 2,3-pentylene carbonate and the like.
Of these, ethylene carbonate and propylene carbonate having a high dielectric constant are preferable. In the case of a battery using a negative electrode active material containing graphite, it is more preferable that the non-aqueous solvent contains ethylene carbonate.

Examples of the chain carbonate compound include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl propyl carbonate, methyl isopropyl carbonate, ethyl propyl carbonate, dipropyl carbonate, methyl butyl carbonate, ethyl butyl carbonate, dibutyl carbonate, methyl pentyl carbonate, and ethyl pentyl. Examples thereof include carbonate, dipentyl carbonate, methylheptyl carbonate, ethylheptyl carbonate, diheptyl carbonate, methylhexyl carbonate, ethylhexyl carbonate, dihexyl carbonate, methyloctyl carbonate, ethyloctyl carbonate, dioctyl carbonate and the like.

Specific combinations of cyclic carbonate and chain carbonate include ethylene carbonate and dimethyl carbonate, ethylene carbonate and methyl ethyl carbonate, ethylene carbonate and diethyl carbonate, propylene carbonate and dimethyl carbonate, propylene carbonate and methyl ethyl carbonate, and propylene carbonate. Diethyl carbonate, ethylene carbonate and propylene carbonate and methyl ethyl carbonate, ethylene carbonate and propylene carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate and methyl ethyl carbonate, ethylene carbonate and dimethyl carbonate and diethyl carbonate, ethylene carbonate and methyl ethyl carbonate and diethyl carbonate. , Ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and methyl ethyl carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate and diethyl carbonate, ethylene carbonate, propylene carbonate, methyl ethyl carbonate and diethyl Examples thereof include carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, methyl ethyl carbonate and diethyl carbonate.

The mixing ratio of the cyclic carbonate compound and the chain carbonate compound is expressed in terms of mass ratio, and the cyclic carbonate compound: chain carbonate compound is, for example, 5:95 to 80:20, preferably 10:90 to 70:30, more preferably. Is 15:85 to 55:45. By setting such a ratio, it is possible to suppress an increase in viscosity of the non-aqueous electrolyte solution and increase the degree of dissociation of the electrolyte, so that the conductivity of the non-aqueous electrolyte solution related to the charge / discharge characteristics of the battery can be increased. .. Moreover, the solubility of the electrolyte can be further increased. Therefore, since the non-aqueous electrolytic solution having excellent electrical conductivity at room temperature or low temperature can be obtained, the load characteristics of the battery at room temperature to low temperature can be improved.

The non-aqueous solvent may contain other compounds other than the cyclic carbonate compound and the chain carbonate compound.
In this case, the other compounds contained in the non-aqueous solvent may be only one kind or two or more kinds.
Other compounds include cyclic carboxylic acid ester compounds (for example, γ butyrolactone), cyclic sulfone compounds, cyclic ether compounds, chain carboxylic acid ester compounds, chain ether compounds, chain phosphate ester compounds, amide compounds, and chain carbamate. Examples thereof include compounds, cyclic amide compounds, cyclic urea compounds, boron compounds, polyethylene glycol derivatives, and the like.
For these compounds, the description in paragraphs 0069 to 0087 of JP-A-2017-45723 can be appropriately referred to.

The ratio of the cyclic carbonate compound and the chain carbonate compound in the non-aqueous solvent is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably 95% by mass or more.
The ratio of the cyclic carbonate compound and the chain carbonate compound in the non-aqueous solvent may be 100% by mass.

The ratio of the non-aqueous solvent to the non-aqueous electrolytic solution is preferably 60% by mass or more, and more preferably 70% by mass or more.
The upper limit of the ratio of the non-aqueous solvent to the non-aqueous electrolyte solution depends on the content of other components (electrolytes, additives, etc.), but the upper limit is, for example, 99% by mass, preferably 97% by mass. Yes, more preferably 90% by mass.

[Lithium-ion secondary battery]
The lithium ion secondary battery of the present disclosure is
A positive electrode containing a positive electrode active material layer containing a positive electrode active material, and a positive electrode
A negative electrode containing a negative electrode active material layer containing a negative electrode active material, and a negative electrode
The above-mentioned non-aqueous electrolyte solution for batteries of the present disclosure and
To be equipped.
In the lithium ion secondary battery of the present disclosure, deterioration of battery characteristics after storage is reduced.
Such an effect is an effect brought about by the combination of Additives A to C contained in the non-aqueous electrolytic solution.

<Positive electrode>
The positive electrode includes a positive electrode active material layer containing a positive electrode active material. The positive electrode active material preferably contains a lithium nickel-manganese-cobalt composite oxide. As the lithium nickel-manganese-cobalt composite oxide, a compound represented by the following formula (P1) is preferable.

_{LiNi x Mn y Co z O 2} ... (P1)
[In the formula (P1), x, y and z are independently more than 0 and less than 1.00, and the sum of x, y and z is 0.99 to 1.00. ]

In the formula (P1), x is preferably 0.10 to 0.90, more preferably 0.30 to 0.90, still more preferably 0.50 to 0.90, still more preferably. It is more than 0.50 and 0.90 or less, more preferably 0.55 to 0.90, and further preferably 0.60 to 0.80.
In the formula (P1), y is preferably 0.10 to 0.90, more preferably 0.10 to 0.50, and even more preferably 0.25 to 0.40.
In the formula (P1), z is preferably 0.10 to 0.90, more preferably 0.10 to 0.50, and even more preferably 0.10 to 0.30.

Examples of the compound represented by the formula (P1) include LiNi _0.33 Mn _0.33 Co _0.33 O ₂ , LiNi _0.5 Mn _0.3 Co _0.2 O ₂ , and LiNi _0.6 Mn _0.2. Co _0.2 O ₂ or LiNi _0.8 Mn _0.1 Co _0.1 O ₂ is preferable, and LiNi _0.5 Mn _0.3 Co _0.2 O ₂ and LiNi _0.6 Mn _0.2 Co _{0 .2} O ₂ or LiNi _0.8 Mn _0.1 Co _0.1 O ₂ is more preferable, and LiNi _0.6 Mn _0.2 Co _0.2 O ₂ or LiNi _0.8 Mn _0.1 Co _{0. 1} O ₂ is more preferable.

The positive electrode may contain a component other than the lithium nickel manganese cobalt composite oxide as the positive electrode active material.
As a component other than lithium nickel manganese cobalt composite oxide;
Transition metal oxides or transition metal sulfides such as MoS ₂ , TiS ₂ , MnO ₂ , V ₂ O _5;
A composite oxide consisting of lithium and a transition metal, such as _{LiCoO 2} , LiMnO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiNi _X Co _(1-X) O ₂ [0 <X <1], LiFePO ₄ , LiMnPO _4. (However, lithium nickel manganese cobalt composite oxide is excluded);
Conductive polymer materials such as polyaniline, polythiophene, polypyrrole, polyacetylene, polyacene, dimercaptothiadiazole, polyaniline complex;
And so on.

The proportion of the lithium nickel manganese cobalt composite oxide in the positive electrode active material is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.
The ratio of the lithium nickel manganese cobalt composite oxide in the positive electrode active material may be 100% by mass or less than 100% by mass.

The positive electrode preferably includes a positive electrode active material layer containing a positive electrode active material.
The positive electrode active material layer may contain components other than the positive electrode active material.
Examples of the components other than the positive electrode active material include a conductive auxiliary agent, a binder, and the like.
Examples of the conductive auxiliary agent include carbon materials such as carbon black (for example, acetylene black), amorphous whiskers, and graphite.
Examples of the binder include polyvinylidene fluoride and the like.

The positive electrode active material layer can be formed by applying a positive electrode mixture slurry containing a positive electrode active material and a solvent onto a positive electrode current collector described later and drying the mixture.
The positive electrode mixture slurry may contain components other than the positive electrode active material (for example, a conductive auxiliary agent, a binder, etc.).
Examples of the solvent in the positive electrode mixture slurry include an organic solvent such as N-methylpyrrolidone.

The ratio of the positive electrode active material to the total solid content of the positive electrode active material layer is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.
The ratio of the positive electrode active material to the total solid content of the positive electrode active material layer may be 100% by mass.
Here, the total solid content of the positive electrode active material layer means the total amount of the positive electrode active material layer excluding the solvent when the solvent remains in the positive electrode active material layer, and the solvent is contained in the positive electrode active material layer. If it does not remain, it means the total amount of the positive electrode active material layer.

The ratio of the lithium nickel manganese cobalt composite oxide to the total solid content of the positive electrode active material layer is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.
The ratio of the lithium nickel manganese cobalt composite oxide to the total solid content of the positive electrode active material layer may be 100% by mass or less than 100% by mass.

The positive electrode preferably includes a positive electrode current collector.
The material of the positive electrode current collector is not particularly limited, and any known material can be used.
Specific examples of the positive electrode current collector include metal materials such as aluminum, aluminum alloy, stainless steel, nickel, titanium, and tantalum; carbon materials such as carbon cloth and carbon paper; and the like.

<Negative electrode>
The negative electrode includes a negative electrode active material layer containing a negative electrode active material.
Examples of the negative electrode active material include metallic lithium, lithium-containing alloys, metals or alloys that can be alloyed with lithium, oxides that can be doped / dedoped with lithium ions, and lithium ions that can be doped / dedoped. At least one selected from the group consisting of transition metal nitridants and carbon materials capable of doping and dedoping lithium ions can be used.
Examples of the metal or alloy that can be alloyed with lithium (or lithium ion) include silicon, a silicon alloy, tin, and a tin alloy.
Examples of the oxide capable of doping and dedoping lithium ions include lithium titanate, silicon oxide (preferably SiOx (X represents 0.5 or more and less than 1.6), and more preferably SiO). Can be done.
Among these, a carbon material capable of doping and dedoping lithium ions is preferable.
Examples of such carbon materials include carbon black, activated carbon, graphite materials (artificial graphite, natural graphite), amorphous carbon materials, and the like. The form of the carbon material may be any of fibrous, spherical, potato-like, and flake-like forms.

Specific examples of the amorphous carbon material include hard carbon, coke, mesocarbon microbeads (MCMB) fired at 1500 ° C. or lower, and mesophase pitch carbon fiber (MCF).
Examples of the graphite material include natural graphite and artificial graphite. As the artificial graphite, graphitized MCMB, graphitized MCF and the like are used. Further, as the graphite material, a material containing boron or the like can also be used. Further, as the graphite material, a material coated with a metal such as gold, platinum, silver, copper or tin, a material coated with amorphous carbon, or a mixture of amorphous carbon and graphite can also be used.

These carbon materials may be used alone or in admixture of two or more.
As the carbon material, a carbon material having a surface spacing d (002) of the (002) plane measured by X-ray analysis of 0.340 nm or less is particularly preferable. Further, as the carbon material, graphite having a true density of 1.70 g / cm ³ or more or a highly crystalline carbon material having a property close to that of graphite is also preferable. When the carbon material as described above is used, the energy density of the battery can be further increased.

The ratio of the carbon material (preferably graphite material) to the negative electrode active material is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.
The ratio of the carbon material (preferably graphite material) to the negative electrode active material may be 100% by mass or less than 100% by mass.

The negative electrode preferably includes a negative electrode active material layer containing a negative electrode active material.
The negative electrode active material layer may contain components other than the negative electrode active material.
Examples of the component other than the negative electrode active material include a binder.
Examples of the binder include carboxymethyl cellulose and SBR latex.

The negative electrode active material layer can be formed by applying a negative electrode mixture slurry containing a negative electrode active material and a solvent onto a negative electrode current collector described later and drying it.
The negative electrode mixture slurry may contain a component (for example, a binder) other than the negative electrode active material.
Examples of the solvent in the negative electrode mixture slurry include water.

The ratio of the negative electrode active material to the total solid content of the negative electrode active material layer is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.
The ratio of the negative electrode active material to the total solid content of the negative electrode active material layer may be 100% by mass.
Here, the total solid content of the negative electrode active material layer means the total amount of the negative electrode active material layer excluding the solvent when the solvent remains in the negative electrode active material layer, and the solvent is contained in the negative electrode active material layer. If it does not remain, it means the total amount of the negative electrode active material layer.

The ratio of the carbon material (preferably graphite material) to the total solid content of the negative electrode active material layer is preferably 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more. ..
The ratio of the carbon material (preferably graphite material) to the total solid content of the negative electrode active material layer may be 100% by mass.

The negative electrode preferably includes a negative electrode current collector.
The material of the negative electrode current collector is not particularly limited, and any known material can be used.
Specific examples of the negative electrode current collector include metal materials such as copper, nickel, stainless steel, and nickel-plated steel. Of these, copper is particularly preferable from the viewpoint of ease of processing.

<Separator>
The lithium ion secondary battery of the present disclosure preferably includes a separator between the negative electrode and the positive electrode.
The separator is a membrane that electrically insulates the positive electrode and the negative electrode and allows lithium ions to pass through, and examples thereof include a porous membrane and a polymer electrolyte.
As the porous film, a microporous polymer film is preferably used, and examples of the material include polyolefin, polyimide, polyvinylidene fluoride, polyester and the like.
In particular, porous polyolefin is preferable, and specifically, a porous polyethylene film, a porous polypropylene film, or a multilayer film of a porous polyethylene film and a polypropylene film can be exemplified. The porous polyolefin film may be coated with another resin having excellent thermal stability.
Examples of the polymer electrolyte include a polymer in which a lithium salt is dissolved, a polymer inflated with an electrolytic solution, and the like.
The non-aqueous electrolyte solution of the present disclosure may be used for the purpose of swelling a polymer to obtain a polymer electrolyte.

<Battery configuration>
The lithium ion secondary battery of the present disclosure can take various known shapes, and can be formed into a cylindrical type, a coin type, a square type, a laminated type, a film type, or any other shape. However, the basic structure of the battery is the same regardless of the shape, and the design can be changed according to the purpose.

An example of the lithium ion secondary battery of the present disclosure is a laminated battery.
FIG. 1 is a schematic perspective view showing an example of a laminated battery which is an example of the lithium ion secondary battery of the present disclosure, and FIG. 2 is a thickness of a laminated electrode body housed in the laminated battery shown in FIG. It is a schematic cross-sectional view in the longitudinal direction.
The laminated battery shown in FIG. 1 contains a non-aqueous electrolytic solution (not shown in FIG. 1) and a laminated electrode body (not shown in FIG. 1), and the peripheral edge thereof is sealed. A laminated exterior body 1 whose inside is hermetically sealed is provided. As the laminated exterior body 1, for example, a laminated exterior body made of aluminum is used.
As shown in FIG. 2, the laminated electrode body housed in the laminated exterior body 1 is a laminated body in which a positive electrode plate 5 and a negative electrode plate 6 are alternately laminated via a separator 7, and a laminated body of the laminated body. A separator 8 that surrounds the periphery is provided. The positive electrode plate 5, the negative electrode plate 6, the separator 7, and the separator 8 are impregnated with the non-aqueous electrolytic solution of the present disclosure. The positive electrode plate 5 includes a positive electrode current collector and a positive electrode active material layer. The negative electrode plate 5 includes a negative electrode current collector and a negative electrode active material layer.
The plurality of positive electrode plates 5 in the laminated electrode body are all electrically connected to the positive electrode terminal 2 via the positive electrode tab (not shown), and a part of the positive electrode terminal 2 is the laminated exterior body 1. It protrudes outward from the peripheral end (Fig. 1). A portion of the peripheral end of the laminated exterior body 1 on which the positive electrode terminal 2 protrudes is sealed with an insulating seal 4.
Similarly, the plurality of negative electrode plates 6 in the laminated electrode body are all electrically connected to the negative electrode terminal 3 via the negative electrode tab (not shown), and a part of the negative electrode terminal 3 is the laminated exterior. It protrudes outward from the peripheral end of the body 1 (FIG. 1). A portion of the peripheral end of the laminated exterior body 1 from which the negative electrode terminal 3 protrudes is sealed with an insulating seal 4.
In the laminated battery according to the above example, the number of positive electrode plates 5 is 5 and the number of negative electrode plates 6 is 6, and the positive electrode plate 5 and the negative electrode plate 6 are located on both sides of the battery via the separator 7. The outer layers are all laminated so as to be the negative electrode plate 6. However, it goes without saying that the number of positive electrode plates, the number of negative electrode plates, and the arrangement of the laminated battery are not limited to this example, and various changes may be made.

Another example of the lithium ion secondary battery of the present disclosure is a coin-type battery.
FIG. 3 is a schematic perspective view showing an example of a coin-type battery, which is another example of the lithium ion secondary battery of the present disclosure.
In the coin-type battery shown in FIG. 3, a disk-shaped negative electrode 12, a separator 15 injected with a non-aqueous electrolyte solution, a disk-shaped positive electrode 11, and, if necessary, spacer plates 17 and 18 made of stainless steel or aluminum are arranged in this order. In a laminated state, it is stored between the positive electrode can 13 (hereinafter, also referred to as “battery can”) and the sealing plate 14 (hereinafter, also referred to as “battery can lid”). The positive electrode can 13 and the sealing plate 14 are caulked and sealed via the gasket 16.
In this example, the non-aqueous electrolytic solution of the present disclosure is used as the non-aqueous electrolytic solution to be injected into the separator 15. The disk-shaped positive electrode 11 includes a positive electrode current collector and a positive electrode active material layer. The disk-shaped negative electrode 12 includes a negative electrode current collector and a negative electrode active material layer.

In the lithium ion secondary battery of the present disclosure, a lithium ion secondary battery (lithium ion secondary battery before charging / discharging) including a positive electrode, a negative electrode, and the non-aqueous electrolyte solution of the present disclosure is charged and discharged. The lithium ion secondary battery thus obtained may be used.
That is, in the lithium ion secondary battery of the present disclosure, first, a lithium ion secondary battery before charging / discharging including a positive electrode, a negative electrode, and a non-aqueous electrolyte solution of the present disclosure is prepared, and then before charging / discharging. It may be a lithium ion secondary battery (charged / discharged lithium ion secondary battery) manufactured by charging / discharging the lithium ion secondary battery of the above once or more.

The application of the lithium ion secondary battery of the present disclosure is not particularly limited, and can be used for various known applications. For example, laptops, mobile computers, mobile phones, headphone stereos, video movies, LCD TVs, handy cleaners, electronic organizers, calculators, radios, backup power supplies, motors, automobiles, electric vehicles, bikes, electric bikes, bicycles, electric It can be widely used regardless of whether it is a small portable device or a large device such as a bicycle, a lighting device, a game machine, a clock, an electric tool, or a camera.

Hereinafter, examples of the present disclosure will be shown, but the present disclosure is not limited to the following examples.
In the following examples, the "addition amount" means the content in the finally obtained non-aqueous electrolyte solution (that is, the amount with respect to the total amount of the finally obtained non-aqueous electrolyte solution).
Further, "wt%" means mass%.

[Example 1]
A coin-type battery (test battery), which is a lithium-ion secondary battery, was produced by the following procedure.
<Manufacturing of negative electrode>
Amorphous coated natural graphite (97 parts by mass), carboxymethyl cellulose (1 part by mass) and SBR latex (2 parts by mass) were kneaded with an aqueous solvent to prepare a paste-like negative electrode mixture slurry.
Next, this negative electrode mixture slurry is applied to a negative electrode current collector made of a strip-shaped copper foil having a thickness of 10 μm, dried, and then compressed by a roll press to form a sheet-shaped negative electrode composed of a negative electrode current collector and a negative electrode active material layer. Got At this time, the coating density of the negative electrode active material layer was 12 mg / cm ² , and the packing density was 1.5 g / ml.

<Preparation of positive electrode>
LiNi _0.5 Mn _0.3 Co _0.2 O ₂ (90 parts by mass), acetylene black (5 parts by mass) and polyvinylidene fluoride (5 parts by mass) are kneaded with N-methylpyrrolidinone as a solvent to form a paste. A positive electrode mixture slurry was prepared.
Next, this positive electrode mixture slurry is applied to a positive electrode current collector of a strip-shaped aluminum foil having a thickness of 20 μm, dried, and then compressed by a roll press to form a sheet-shaped positive electrode composed of a positive electrode current collector and a positive electrode active material layer. Got At this time, the coating density of the positive electrode active material layer was 22 mg / cm ² , and the packing density was 2.5 g / ml.

<Preparation of non-aqueous electrolyte solution>
As a non-aqueous solvent, ethylene carbonate (EC), dimethyl carbonate (DMC) and methyl ethyl carbonate (EMC) were mixed at a ratio of 30:35:35 (mass ratio) to obtain a mixed solvent.
_{LiPF 6} as an electrolyte was dissolved in the obtained mixed solvent so that the electrolyte concentration in the finally prepared non-aqueous electrolyte solution was 1 mol / liter.
With respect to the obtained solution, as additives, it is represented by MSF (methanesulfonyl fluoride), vinylene carbonate (VC), and formula (C1-1), which are specific examples of the compound represented by the formula (A1). The contents of each of the compounds (hereinafter, also referred to as “compound (C1-1)”) with respect to the total mass of the finally prepared non-aqueous electrolyte solution are 0.5% by mass, 0.2% by mass, and 0. Addition was made in an amount of .5% by mass to obtain a non-aqueous electrolyte solution.

<Making coin-type batteries>
The above-mentioned negative electrode was punched in a disk shape with a diameter of 14 mm and the above-mentioned positive electrode was punched in a disk shape, respectively, to obtain a coin-shaped negative electrode and a coin-shaped positive electrode, respectively. Further, a microporous polyethylene film having a thickness of 20 μm was punched into a disk shape having a diameter of 17 mm to obtain a separator.
The obtained coin-shaped negative electrode, separator, and coin-shaped positive electrode were laminated in a stainless steel battery can (2032 size) in this order, and then 20 μL of the above-mentioned non-aqueous electrolyte solution was placed in the battery can. It was injected and immersed in the separator, the positive electrode and the negative electrode.
Next, an aluminum plate (thickness 1.2 mm, diameter 16 mm) and a spring were placed on the positive electrode, and the battery was sealed by crimping the battery can lid via a polypropylene gasket.
As described above, a coin-type battery (that is, a coin-type lithium-ion secondary battery) having a diameter of 20 mm and a height of 3.2 mm and having the configuration shown in FIG. 3 was obtained.

<Evaluation>
The following evaluations were carried out on the obtained coin-type batteries.
The evaluation results are shown in Table 1.
In Table 1, the initial resistance (that is, the resistance before storage), the resistance after storage, and the resistance increase rate during storage (also simply referred to as “increased rate”) of the coin-type batteries obtained in each example are shown. Shown.

In the following
"Conditioning" means that a coin-cell battery is charged and discharged three times between 2.75V and 4.25V at 25 ° C. in a constant temperature bath.
"Preservation" means an operation of storing a coin-type battery in a constant temperature bath at 60 ° C. for 10 days.
Hereinafter, the DC resistance was measured under a temperature condition of 25 ° C.

(Measurement of initial resistance)
The SOC (State of Charge) of the coin cell battery after conditioning is adjusted to 50%, and then the DCIR (Direct current internal resistance) of the initial (that is, before storage) of the coin cell battery is adjusted by the following method. It was measured.
Using the above-mentioned coin-type battery adjusted to SOC 50%, CC discharge was performed for 10 seconds at a discharge rate of 0.2C to 5C.
Here, CC10s discharge means to discharge at a constant current for 10 seconds.
Each current value (that is, a current value corresponding to a discharge rate of 0.2C to 5C) in the above "CC discharge at a discharge rate of 0.2C to 5C" and each voltage decrease amount corresponding to each current value (= discharge start). The DC resistance (Ω) was calculated based on the previous voltage − the voltage 10 seconds after the start of discharge). The obtained DC resistance (Ω) was defined as the initial resistance (that is, the resistance before storage) (Ω). The results are shown in Table 1.

(Measurement of resistance after storage)
An operation in which a coin-type battery after conditioning and before adjusting the SOC to 50% is charged with CC-CV to 4.25 V at a charging rate of 0.2 C in a constant temperature bath, and then "preserved" under the above conditions is performed. The resistance (Ω) after storage was measured in the same manner as the above-mentioned measurement of the initial resistance except that. The results are shown in Table 1.
Here, CC-CV charging means a constant current-constant voltage.

(Calculation of resistance increase rate during storage)
The resistance increase rate during storage was calculated by the following formula.
Resistance increase rate during storage = ((resistance after storage (Ω) / initial resistance (Ω)) x 100)

Table 1 shows the rate of increase in resistance during storage (also simply referred to as “rate of increase”).
Here, the rate of increase means that when the value exceeds 100, the DC resistance of the battery after storage has increased compared to the initial resistance, and when it is less than 100, the DC resistance of the battery after storage has increased. It means that it has decreased compared to the initial resistance.

[Examples 2 to 6, Comparative Examples 1 to 5]
The same operation as in Example 1 was carried out except that the combination of the type and the amount of each additive contained in the non-aqueous electrolytic solution was changed as shown in Table 1.
The results are shown in Table 1.
In addition, in Table 1, "-" means that the corresponding additive is not contained.

As shown in Table 1, in Examples 1 to 6 in which all of Additives A to C are contained in the non-aqueous electrolytic solution, the increase in battery resistance due to storage is reduced as compared with Comparative Examples 1 to 5 (Table 1). (See "Rise rate").

Claims (9)

Electrolytes containing lithium hexafluorophosphate and
Additive A, which is at least one selected from the group consisting of compounds represented by the following formula (A1), and
Additive B, which is vinylene carbonate, and
Additive C, which is at least one selected from the group consisting of the compound represented by the following formula (C1) and the compound represented by the following formula (C2), and
A non-aqueous electrolyte solution for batteries containing.

[In the formula (A1), ^Ra1 is a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbon oxy group having 1 to 6 carbon atoms, or a fluorinated hydrocarbon group having 1 to 6 carbon atoms. Represents.
In the formula (C1), R ^{c11 to} R ^c14 are independently each of a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by the formula (a), or a group represented by the formula (b). Represents. In formulas (a) and (b), * represents a coupling position.
In the formula (C2), R ^{c21 to} R ^c24 independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms. ] The non-aqueous electrolytic solution for a battery according to claim 1, wherein the content of the additive A is 0.1% by mass or more and 2.0% by mass or less with respect to the total amount of the non-aqueous electrolytic solution. The non-aqueous electrolytic solution for a battery according to claim 1 or 2, wherein the content of the additive B is 0.1% by mass or more and 2.0% by mass or less with respect to the total amount of the non-aqueous electrolytic solution. The non-battery according to any one of claims 1 to 3, wherein the content of the additive C is 0.1% by mass or more and 2.0% by mass or less with respect to the total amount of the non-aqueous electrolytic solution. Water electrolyte.
The non-aqueous electrolyte solution for batteries according to any one of claims 1 to 4, wherein the concentration of the electrolyte is 0.1 mol / L or more and 3 mol / L or less with respect to the total amount of the non-aqueous electrolyte solution. A positive electrode containing a positive electrode active material layer containing a positive electrode active material, and a positive electrode
A negative electrode containing a negative electrode active material layer containing a negative electrode active material, and a negative electrode
The non-aqueous electrolyte solution for a battery according to any one of claims 1 to 5.
Lithium-ion secondary battery with. The lithium ion secondary battery according to claim 6, wherein the positive electrode active material contains a lithium nickel manganese cobalt composite oxide. The lithium ion secondary battery according to claim 6 or 7, wherein the negative electrode active material contains a carbon material. A lithium ion secondary battery obtained by charging / discharging the lithium ion secondary battery according to any one of claims 6 to 8.

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