JP2018037388A - Additive agent for nonaqueous electrolyte, nonaqueous electrolyte using the same, and nonaqueous electrolytic secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an additive agent for a nonaqueous electrolyte, which is allowed to exhibit cycle and rate characteristics with good balance when it is used for a nonaqueous electrolytic secondary battery by addition to a nonaqueous electrolyte together with an oxalate salt and/or difluorophosphate.SOLUTION: An additive agent for a nonaqueous electrolyte comprises a compound having a repeating unit represented by the general formula [1], of which the number average molecular weight is 170-5000 in terms of polystyrene. The additive agent for a nonaqueous electrolyte is arranged on the assumption that a nonaqueous electrolyte including oxalate salt and/or difluorophosphate contains the additive agent. [In the formula, the bracket contents indicate the repeating unit; R's each represent a hydrogen atom, halogen or a lower alkyl group, and the R's may be the same or not, and they may bind to each other to form a cyclic structure.]SELECTED DRAWING: None

Description

  The present invention relates to an additive for a non-aqueous electrolyte solution, a non-aqueous electrolyte solution using the additive, and a non-aqueous electrolyte secondary battery.

  So far, as a means for improving the durability of non-aqueous electrolyte batteries, optimization of various battery components including positive and negative electrode active materials has been studied. Non-aqueous electrolytes are no exception, and it has been proposed to suppress deterioration due to decomposition of the electrolyte on the surface of the active positive electrode or negative electrode by electrolysis coatings with various durability improvers.

  For example, Patent Document 1 discloses non-aqueous oxalate salts such as difluoro (bis (oxalato)) lithium phosphate, tetrafluoro (oxalato) lithium phosphate, difluoro (oxalato) lithium borate, and bis (oxalato) lithium borate. There has been proposed a method for suppressing an increase in internal resistance and deterioration of cycle characteristics of a battery by adding it to an electrolytic solution.

  Moreover, in patent document 2, in order to form a passivation layer on an electrode in a lithium ion secondary battery, at least one unsaturated bond is formed at a ratio of 0.01 to 10% by mass of the nonaqueous electrolytic solution. An electrolyte solution for a secondary battery is disclosed, characterized in that a soluble compound that can be reduced at the anode at a potential 1 V higher than lithium is added to form a passivation layer. As the soluble compound containing the unsaturated bond, for example, adding a carbonate compound having an unsaturated bond typified by vinylene carbonate (hereinafter sometimes referred to as “VC”) is disclosed.

Moreover, in patent document 3, in a lithium ion secondary battery, in order to improve the capacity | capacitance maintenance factor after repeating a charging / discharging cycle at high temperature, with respect to 100 mass parts of non-aqueous electrolyte, VC and Li [M (C ₂ O ₄ ) _x R _y ] (wherein M is one selected from the group consisting of P, Al, Si and C, R is a group consisting of a halogen group, an alkyl group and a halogenated alkyl group) A total of 0.6 parts by mass or more and 3.9 parts by mass or less of an oxalato salt represented by one group selected from the above, x is a positive integer, y is 0 or a positive integer) A secondary battery electrolyte solution is disclosed.

  Further, in Patent Document 4, at least non-aqueous electrolyte is provided for the purpose of providing a non-aqueous electrolyte for a secondary battery that suppresses a decrease in repeated charge / discharge characteristics (cycle characteristics) of the battery and is excellent in low-temperature discharge characteristics. A non-aqueous electrolyte solution for a secondary battery containing a solvent, a lithium salt and vinylene carbonate, wherein the vinylene carbonate content is in the range of 0.001% by mass to 3% by mass of the total electrolyte solution mass, and In addition, a non-aqueous electrolyte solution for a secondary battery is disclosed that contains difluorophosphate in an amount of 10 ppm or more based on the total mass of the electrolyte solution.

  The durability improving additive containing an unsaturated bond as described above is generally added as a monomer body. For example, in the case where VC is added, in Patent Document 5, a polymerization inhibitor is also added so that the battery does not swell due to a reaction at a portion other than that where VC should function. Moreover, in patent document 6, when forming the polymer gel layer containing the electrolyte solution containing VC, it is made to gelatinize by cationic polymerization, a free radical seed | species does not exist in a system, VC in electrolyte solution Is suppressed by the self-polymerization reaction. Thus, the durability improving additive containing an unsaturated bond has been conventionally added as a monomer body.

JP 2005-032714 A JP-A-8-045545 International Publication No. 2010/067549 JP 2007-141830 A JP 2008-034233 A JP 2008-282735 A

When a non-aqueous electrolyte solution containing an oxalato salt and / or difluorophosphate and a carbonate compound containing an unsaturated bond that has been added as a conventional monomer body is used in a non-aqueous electrolyte secondary battery, Although excellent cycle characteristics are exhibited, the rate characteristics tend to be low, and improvement is desired.
Therefore, the present invention can exhibit cycle characteristics and rate characteristics in a well-balanced manner when used in a non-aqueous electrolyte secondary battery by adding it together with an oxalato salt and / or difluorophosphate to a non-aqueous electrolyte. An object of the present invention is to provide an additive for a non-aqueous electrolyte solution.
It is another object of the present invention to provide a non-aqueous electrolyte solution having the non-aqueous electrolyte solution additive.
It is another object of the present invention to provide a non-aqueous electrolyte secondary battery including the non-aqueous electrolyte.

［式中、括弧の内部はそれぞれが繰り返し単位であることを意味する。Ｒは、水素原子、ハロゲン又は低級アルキル基を表す。Ｒは、全て同一であってもよく、異なっていてもよく、互いに連結して環状構造を有していてもよい。］ The present invention
A compound having a repeating unit represented by the following general formula [1]:
The number average molecular weight in terms of polystyrene is 170 to 5000,
It is an additive for a non-aqueous electrolyte solution for inclusion in a non-aqueous electrolyte solution containing an oxalato salt and / or a difluorophosphate.

[Wherein the parentheses mean that each is a repeating unit. R represents a hydrogen atom, a halogen or a lower alkyl group. R may be all the same or different, and may be linked to each other to have a cyclic structure. ]

  The number average molecular weight is preferably 340 to 4000, and more preferably 800 to 3000.

  It is preferable that all the Rs are hydrogen atoms.

［式中、括弧の内部はそれぞれが繰り返し単位であることを意味する。Ｒは、水素原子、ハロゲン又は低級アルキル基を表す。Ｒは、全て同一であってもよく、異なっていてもよく、互いに連結して環状構造を有していてもよい。］ The present invention also provides:
(I) Oxalato salt and / or difluorophosphate,
(II) A compound having a repeating unit represented by the following general formula [1], and having a polystyrene-equivalent number average molecular weight of 170 to 5,000, an additive for non-aqueous electrolyte solution,
(III) a non-aqueous organic solvent, and
(IV) A nonaqueous electrolytic solution containing a solute.

[Wherein the parentheses mean that each is a repeating unit. R represents a hydrogen atom, a halogen or a lower alkyl group. R may be all the same or different, and may be linked to each other to have a cyclic structure. ]

  In the non-aqueous electrolyte solution, the number average molecular weight is preferably 340 to 4000, and more preferably 800 to 3000.

  In the non-aqueous electrolyte solution, it is preferable that all Rs are hydrogen atoms.

  It is preferable that the content of (II) is 0.03 to 14.0% by mass with respect to 100% by mass of the total amount of (I), (II), (III) and (IV).

Present in the electrolyte,
A total amount of monomers (hereinafter referred to as (M)) corresponding to the repeating unit represented by the general formula [1],
The total amount of the non-aqueous electrolyte additive (in terms of monomer, hereinafter referred to as (P))
(M) / (P) = 0-0.05 (mass ratio)
It is preferable that

  The oxalato salt comprises bis (oxalato) borate, difluoro (oxalato) borate, tris (oxalato) phosphate, difluorobis (oxalato) phosphate, and tetrafluoro (oxalato) phosphate. It is preferably at least one selected from the group.

The solute is lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), bis (trifluoromethanesulfonyl) imidolithium (LiN (CF ₃ SO ₂ ) ₂ ), bis (pentafluoroethanesulfonyl) Consists of imidolithium (LiN (C ₂ F ₅ SO ₂ ) ₂ ), bis (fluorosulfonyl) imide lithium (LiN (FSO ₂ ) ₂ ), and bis (difluorophosphonyl) imide lithium (LiN (POF ₂ ) ₂ ) It is preferably at least one selected from the group.

  The electrolyte solution preferably contains at least lithium difluorobis (oxalato) phosphate and lithium difluorophosphate as (I).

  The non-aqueous solvent is preferably at least one selected from the group consisting of cyclic carbonates, chain carbonates, cyclic esters, chain esters, cyclic ethers, chain ethers, sulfone compounds, sulfoxide compounds, and ionic liquids. .

In addition, the electrolyte solution is
Ionic complex having cyclic structure, salt having imide anion, Si-containing compound, sulfate ester compound, phosphate ester compound, cyclic carbonate compound, isocyanate compound, cyclic acetal compound, cyclic acid anhydride, cyclic phosphazene compound, aromatic compound At least one compound selected from the group consisting of:
Furthermore, it is preferable to contain.

  Moreover, this invention is a non-aqueous electrolyte secondary battery provided with at least a positive electrode, a negative electrode, and the non-aqueous electrolyte solution in any one of said.

According to the present invention, when added to a non-aqueous electrolyte solution together with an oxalato salt and / or difluorophosphate, cycle characteristics and rate characteristics can be exhibited in a well-balanced manner when used in a non-aqueous electrolyte secondary battery. A non-aqueous electrolyte additive that can be provided can be provided.
Moreover, when used for a non-aqueous electrolyte secondary battery, it is possible to provide a non-aqueous electrolyte solution and a non-aqueous electrolyte secondary battery that can exhibit a good balance between cycle characteristics and rate characteristics.

  Hereinafter, the present invention will be described in detail. However, the description of the constituent elements described below is an example of an embodiment of the present invention, and the specific contents thereof are not limited. Various modifications can be made within the scope of the gist.

［式中、括弧の内部はそれぞれが繰り返し単位であることを意味する。Ｒは、水素原子、ハロゲン又は低級アルキル基を表す。Ｒは、全て同一であってもよく、異なっていてもよく、共有結合により互いに連結して環状構造を有していてもよい。］ 1. Non-aqueous electrolyte additive The non-aqueous electrolyte additive of the present invention is
A compound having a repeating unit represented by the following general formula [1]:
The number average molecular weight in terms of polystyrene is 170 to 5000,
It is an additive for a non-aqueous electrolyte solution for inclusion in a non-aqueous electrolyte solution containing an oxalato salt and / or a difluorophosphate.

[Wherein the parentheses mean that each is a repeating unit. R represents a hydrogen atom, a halogen or a lower alkyl group. R may be all the same or different, and may be linked to each other by a covalent bond to have a cyclic structure. ]

The additive for non-aqueous electrolyte solution of the present invention is mainly composed of an oligomer of a repeating unit represented by the above general formula [1]. Although the monomer corresponding to the general formula [1] may be included, the content is preferably as small as possible from the viewpoint of cycle characteristics and / or rate characteristics. The additive for non-aqueous electrolyte solution of the present invention is more preferably substantially composed of an oligomer of a repeating unit represented by the above general formula [1].
And it is important that the number average molecular weight of polystyrene conversion of the additive for non-aqueous electrolyte solution is 170-5000.
A compound having a repeating unit represented by the general formula [1] and having the number average molecular weight exhibits cycle characteristics and rate characteristics in a balanced manner when used in a non-aqueous electrolyte secondary battery. The additive for non-aqueous electrolyte solution which can be obtained can be obtained. From the viewpoint of cycle characteristics and / or rate characteristics, the number average molecular weight is preferably 340 to 4000, more preferably 800 to 3000, and particularly preferably 1000 to 2500.

  R in the general formula [1] is a hydrogen atom, a halogen or a lower alkyl group. Examples of the halogen include a fluorine atom, a chlorine atom, and a bromine atom, and examples of the lower alkyl group include a methyl group, an ethyl group, and a propyl group. From the viewpoint of chemical and electrochemical stability and industrial availability, R is preferably a hydrogen atom.

  The non-aqueous electrolyte additive is obtained by polymerizing a corresponding monomer in advance. The polymerization method is not particularly limited as long as it is a generally used method, but it can be polymerized by a radical polymerization method or a photopolymerization method. Of these, radical polymerization is particularly preferred.

  Radical polymerization is carried out in the presence of a radical polymerization initiator or a radical initiator by a known polymerization method such as bulk polymerization, solution polymerization, suspension polymerization or emulsion polymerization, and is either batch-wise, semi-continuous or continuous. Can be implemented by operation.

  The radical initiator is not particularly limited, and examples thereof include azo compounds, peroxide compounds, and redox compounds. For example, 2,2′-azobis (isobutyric acid) dimethyl, azobisisobutyronitrile, t-butyl peroxypivalate, di-t-butyl peroxide, i-butyryl peroxide, lauroyl peroxide, succinic acid peroxide Dicinnamyl peroxide, di-n-propyl peroxydicarbonate, t-butylperoxyallyl monocarbonate, benzoyl peroxide, hydrogen peroxide or ammonium persulfate are preferably used.

  The reactor used in the polymerization reaction for obtaining the polymer represented by the general formula [1] is not particularly limited. In the polymerization reaction, a polymerization solvent may be used. As the polymerization solvent, those which do not inhibit radical polymerization are preferable, such as ester solvent ethyl acetate, n-butyl acetate, ketone solvent acetone, methyl isobutyl ketone, hydrocarbon solvent toluene, cyclohexane, aprotic. Examples thereof include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, dimethylsulfoxide and the like, which are polar solvents. In the polymerization reaction, the reaction temperature is appropriately selected depending on the radical initiator or radical initiator, and is preferably in the range of 20 to 200 ° C, more preferably 30 to 140 ° C. Moreover, you may perform reprecipitation refinement | purification using a poor solvent with respect to the polymer obtained by the polymerization reaction as needed. By removing the monomer by purification such as reprecipitation, it is possible to obtain an additive for a non-aqueous electrolyte substantially consisting of an oligomer of a repeating unit represented by the general formula [1].

2. Non-aqueous electrolyte The non-aqueous electrolyte of the present invention is
(I) Oxalato salt and / or difluorophosphate,
(II) A compound having a repeating unit represented by the general formula [1], and having a polystyrene-equivalent number average molecular weight of 170 to 5,000, an additive for non-aqueous electrolyte solution,
(III) a non-aqueous organic solvent, and
(IV) A nonaqueous electrolytic solution containing a solute.

[(I) Oxalato salt]
There is no particular limitation as long as it is a complex in which an oxalate ion is coordinated to the central element. For example, bis (oxalato) borate, difluoro (oxalato) borate, tris (oxalato) phosphate, difluorobis (oxalato) Examples thereof include phosphate and tetrafluoro (oxalato) phosphate.
Among them, bis (oxalato) borate, difluoro (oxalato) borate, difluorobis (oxalato) phosphate, and from the viewpoint of exhibiting excellent cycle characteristics while preventing excessive generation of gas , At least one selected from the group consisting of tetrafluoro (oxalato) phosphates is preferred.
Bis (oxalato) borate and difluoro (oxalato) borate may be used in combination, bis (oxalato) borate and tris (oxalato) phosphate may be used in combination, or bis ( Oxalato) borate and difluorobis (oxalato) phosphate may be used in combination, bis (oxalato) borate and tetrafluoro (oxalato) phosphate may be used in combination, or difluoro (oxalato) Borate and tris (oxalato) phosphate may be used in combination, difluoro (oxalato) borate and difluorobis (oxalato) phosphate may be used in combination, or difluoro (oxalato) borate And tetrafluoro (oxalato) phosphate may be used in combination, or tris (oxalato) phosphate and difluorobis (oxalato) phosphate may be used in combination. Alternatively, tris (oxalato) phosphate and tetrafluoro (oxalato) phosphate may be used in combination, or bis (oxalato) borate, difluoro (oxalato) borate and tris (oxalato) phosphate. A salt may be used in combination, or bis (oxalato) borate, difluoro (oxalato) borate and difluorobis (oxalato) phosphate may be used in combination, or bis (oxalato) borate and difluoro. (Oxalato) borate and tetrafluoro (oxalato) phosphate may be used in combination, or bis (oxalato) borate, tris (oxalato) phosphate and difluorobis (oxalato) phosphate may be used in combination. Or bis (oxalato) borate, tris (oxalato) phosphate and tetrafluoro (oxalato) phosphate may be used in combination. Bis (oxalato) borate, difluorobis (oxalato) phosphate and tetrafluoro (oxalato) phosphate may be used in combination, or difluoro (oxalato) borate and tris (oxalato) phosphate. And difluorobis (oxalato) phosphate may be used in combination, or difluoro (oxalato) borate, tris (oxalato) phosphate, and tetrafluoro (oxalato) phosphate may be used in combination. (Oxalato) phosphate, difluorobis (oxalato) phosphate and tetrafluoro (oxalato) phosphate may be used in combination, or bis (oxalato) borate, difluoro (oxalato) borate and tris ( Oxalato) phosphate, difluorobis (oxalato) phosphate and tetrafluoro (oxalato) phosphate in combination Also good.

  When the content of (I) is 0.01 to 10.0% by mass with respect to 100% by mass of the total of (I), (II), (III), and (IV), the non-aqueous electrolyte secondary battery When used, it is preferable because the cycle characteristics and rate characteristics are easily exhibited in a well-balanced manner. From the viewpoint of cycle characteristics and / or rate characteristics, the content of (I) is more preferably 0.05 to 5.0% by mass.

When both the oxalato salt and the difluorophosphate are contained, a lithium salt is preferable, and as the oxalate salt, bis (oxalato) lithium borate, difluoro (oxalato) lithium borate, difluorobis (oxalato). ) Lithium phosphate and lithium tetrafluoro (oxalato) phosphate are preferred. Accordingly, lithium difluorophosphate and lithium bis (oxalato) borate may be used in combination, lithium difluorophosphate and lithium difluoro (oxalate) borate may be used in combination, or lithium difluorophosphate and difluorobis (oxalato). ) Lithium phosphate may be used in combination, lithium difluorophosphate and lithium tetrafluoro (oxalato) phosphate may be used in combination, lithium difluorophosphate, lithium bis (oxalato) borate, and difluoro (oxalato) Lithium borate may be used in combination, lithium difluorophosphate, lithium bis (oxalato) borate, and lithium difluorobis (oxalato) phosphate may be used in combination, or lithium difluorophosphate and bis (oxalato) borohydride. Lithium oxide and tetrafluoro (oxa G) Lithium phosphate may be used in combination, lithium difluorophosphate, lithium difluoro (oxalato) borate, and lithium difluorobis (oxalato) phosphate may be used in combination, or lithium difluorophosphate and difluoro (oxalato). ) Lithium borate and tetrafluoro (oxalato) lithium phosphate may be used in combination, or difluorolithium phosphate, difluorobis (oxalato) lithium phosphate and tetrafluoro (oxalato) lithium phosphate may be used in combination. , Lithium difluorophosphate, lithium bis (oxalato) borate, lithium difluoro (oxalato) borate and lithium difluorobis (oxalato) phosphate, or lithium difluorophosphate and lithium bis (oxalato) borate And difluoro (Oki Lato) lithium borate and tetrafluoro (oxalato) lithium phosphate may be used in combination, lithium difluorophosphate, lithium difluoro (oxalato) borate, lithium difluorobis (oxalato) phosphate and tetrafluoro (oxalato) phosphorus Lithium phosphate may be used in combination, or lithium difluorophosphate, lithium bis (oxalato) borate, lithium difluoro (oxalato) borate, lithium difluorobis (oxalato) phosphate, and lithium tetrafluoro (oxalato) phosphate May be.
In particular, the electrolytic solution preferably contains at least lithium difluorobis (oxalato) phosphate and lithium difluorophosphate as (I). In that case, the content of lithium difluorobis (oxalato) phosphate is 0.15 to 2.50% by mass with respect to the total amount of 100% by mass of the above (I), (II), (III), and (IV). The content of lithium difluorophosphate is particularly preferably 0.3 to 3.0% by mass.

[(II) Non-aqueous electrolyte additive]
The non-aqueous electrolyte solution of the present invention contains the above-mentioned additive for non-aqueous electrolyte solution. When the content of (II) is 0.03 to 14.0% by mass with respect to 100% by mass of the total of (I), (II), (III), and (IV), the non-aqueous electrolyte secondary battery When used, it is preferable because the cycle characteristics and rate characteristics are easily exhibited in a well-balanced manner. From the viewpoint of cycle characteristics and / or rate characteristics, the content of (II) is more preferably 0.07 to 12.0 mass%.

[(III) Non-aqueous organic solvent]
If a non-aqueous solvent is used, the non-aqueous electrolyte is generally called a non-aqueous electrolyte, and if a polymer is used, it becomes a polymer solid electrolyte. The polymer solid electrolyte includes those containing a non-aqueous solvent as a plasticizer.

  The non-aqueous organic solvent (III) is not particularly limited as long as it is an aprotic solvent that can dissolve (I), (II), and (IV) of the present invention. For example, carbonates, Esters, ethers, lactones, nitriles, imides, sulfones and the like can be used. Moreover, not only a single solvent but 2 or more types of mixed solvents may be sufficient. Specific examples include ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl butyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4, 5-difluoroethylene carbonate, 4,5-difluoro-4,5-dimethylethylene carbonate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl 2-fluoropropionate, ethyl 2-fluoropropionate, diethyl ether , Acetonitrile, propionitrile, tetrahydrofuran, 2-methyltetrahydrofuran, furan, tetrahydropyran, 1, - dioxane, 1,4-dioxane, dibutyl ether, diisopropyl ether, 1,2-dimethoxyethane, N, N- dimethylformamide, dimethyl sulfoxide, sulfolane, can be mentioned γ- butyrolactone, and γ- valerolactone.

  The polymer used for obtaining the polymer solid electrolyte is not particularly limited as long as it is an aprotic polymer capable of dissolving (I), (II), and (IV). Examples thereof include a polymer having polyethylene oxide in the main chain or side chain, a homopolymer or copolymer of polyvinylidene fluoride, a methacrylic acid ester polymer, polyacrylonitrile and the like. When a plasticizer is added to these polymers, the above-mentioned aprotic non-aqueous solvent can be used.

[(IV) Solute]
The solute is not particularly limited, and a salt composed of an arbitrary cation and anion pair can be used. Specific examples include alkali metal ions such as lithium ions and sodium ions, alkaline earth metal ions, quaternary ammonium, etc. as cations, and hexafluorophosphoric acid, tetrafluoroboric acid, perchloric acid as anions. , Hexafluoroarsenic acid, hexafluoroantimonic acid, trifluoromethanesulfonic acid, bis (trifluoromethanesulfonyl) imide, bis (pentafluoroethanesulfonyl) imide, (trifluoromethanesulfonyl) (pentafluoroethanesulfonyl) imide, bis (fluorosulfonyl) ) Imide, (trifluoromethanesulfonyl) (fluorosulfonyl) imide, (pentafluoroethanesulfonyl) (fluorosulfonyl) imide, tris (trifluoromethanesulfonyl) methide, bis (diphenyl) Orohosuhoniru) imide, (difluoro phosphonyl) (fluorosulfonyl) imide and the like. One kind of these solutes may be used alone, or two or more kinds of solutes may be mixed and used in any combination and ratio according to the application. Among these, considering the energy density, output characteristics, life, etc. of the battery, the cation is preferably at least one selected from the group consisting of lithium, sodium, magnesium and quaternary ammonium, and the anion is hexafluorophosphate, tetra From the group consisting of fluoroboric acid, bis (trifluoromethanesulfonyl) imide, bis (pentafluoroethanesulfonyl) imide, bis (fluorosulfonyl) imide, bis (difluorophosphonyl) imide, (difluorophosphonyl) (fluorosulfonyl) imide At least one selected is preferred.
In particular, lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), bis (trifluoromethanesulfonyl) imide lithium (LiN (CF ₃ SO ₂ ) ₂ ), bis (pentafluoroethanesulfonyl) imide lithium From the group consisting of (LiN (C ₂ F ₅ SO ₂ ) ₂ ), bis (fluorosulfonyl) imide lithium (LiN (FSO ₂ ) ₂ ), and bis (difluorophosphonyl) imide lithium (LiN (POF ₂ ) ₂ ). At least one selected is preferred.

  The total amount of (IV) (hereinafter referred to as “solute concentration”) with respect to the total amount of 100% by mass of (I), (II), (III), and (IV) is not particularly limited, but the lower limit is 0. 5 mol / L or more, preferably 0.7 mol / L or more, more preferably 0.9 mol / L or more, and the upper limit is 5.0 mol / L or less, preferably 4.0 mol / L or less, more preferably 2 The range is 0.0 mol / L or less. When the concentration is less than 0.5 mol / L, the ionic conductivity decreases, thereby reducing the cycle characteristics and output characteristics of the non-aqueous electrolyte secondary battery. On the other hand, when the concentration exceeds 5.0 mol / L, the viscosity of the non-aqueous electrolyte is decreased. If it rises, the ionic conduction may be lowered, and the cycle characteristics and output characteristics of the non-aqueous electrolyte secondary battery may be lowered.

（一般式［２］において、
Ａは金属イオン、プロトン及びオニウムイオンからなる群から選ばれる少なくとも１つであり、
Ｆはフッ素であり、
Ｍは１３族元素（Ａｌ、Ｂ）、１４族元素（Ｓｉ）及び１５族元素（Ｐ、Ａｓ、Ｓｂ）からなる群から選ばれる少なくとも１つであり、
Ｏは酸素であり、
Ｓは硫黄である。
Ｒ^１は炭素数１〜１０の環やヘテロ原子やハロゲン原子を有していてもよい炭化水素基（炭素数が３以上の場合にあっては、分岐鎖あるいは環状構造のものも使用できる）、又は−Ｎ（Ｒ^２）−を表す。このとき、Ｒ^２は水素、アルカリ金属、炭素数１〜１０の環やヘテロ原子やハロゲン原子を有していてもよい炭化水素基を表す。炭素数が３以上の場合にあっては、Ｒ^２は分岐鎖あるいは環状構造をとることもできる。
Ｙは炭素又は硫黄である。Ｙが炭素である場合、ｒは１である。Ｙが硫黄である場合、ｒは１又は２である。
ａは１又は２、ｏは２又は４、ｎは１又は２、ｐは０又は１、ｑは１又は２、ｒは０、１又は２である。ｐが０の場合、Ｓ−Ｙ間に直接結合を形成する。）

（一般式［３］において、
Ａは金属イオン、プロトン及びオニウムイオンからなる群から選ばれる少なくとも１つであり、
Ｆはフッ素であり、
Ｍは１３族元素（Ａｌ、Ｂ）、１４族元素（Ｓｉ）、及び１５族元素（Ｐ、Ａｓ、Ｓｂ）からなる群から選ばれる少なくとも１つであり、
Ｏは酸素であり、
Ｎは窒素である。
Ｙは炭素又は硫黄であり、Ｙが炭素である場合、ｑは１であり、Ｙが硫黄である場合、ｑは１又は２である。
Ｒ^１は炭素数１〜１０の環やヘテロ原子やハロゲン原子を有していてもよい炭化水素基（炭素数が３以上の場合にあっては、分岐鎖あるいは環状構造のものも使用できる）、又は−Ｎ（Ｒ^２）−を表す。このとき、Ｒ^２は水素、アルカリ金属、炭素数１〜１０の環やヘテロ原子やハロゲン原子を有していてもよい炭化水素基を表す。炭素数が３以上の場合にあっては、Ｒ^２は分岐鎖あるいは環状構造をとることもできる。
Ｒ^３は水素、炭素数１〜１０の環やヘテロ原子やハロゲン原子を有していてもよい炭化水素基（炭素数が３以上の場合にあっては、分岐鎖あるいは環状構造のものも使用できる）、又は−Ｎ（Ｒ^２）−を表す。このとき、Ｒ^２は水素、アルカリ金属、炭素数１〜１０の環やヘテロ原子やハロゲン原子を有していてもよい炭化水素基を表す。炭素数が３以上の場合にあっては、Ｒ^２は分岐鎖あるいは環状構造をとることもできる。
ａは１又は２、ｏは２又は４、ｎは１又は２、ｐは０又は１、ｑは１又は２、ｒは０又は１である。ｐが０の場合、Ｒ^１の両隣に位置する原子同士（すなわちＹと炭素原子）が直接結合を形成する。ｒが０の場合Ｍ−Ｎ間に直接結合を形成する。）

（一般式［４］において、
Ｄはハロゲンイオン、ヘキサフルオロリン酸アニオン、テトラフルオロホウ酸アニオン、ビス（トリフルオロメタンスルホニル）イミドアニオン、ビス（フルオロスルホニル）イミドアニオン、（フルオロスルホニル）（トリフルオロメタンスルホニル）イミドアニオン、ビス（ジフルオロホスホニル）イミドアニオンから選ばれる少なくとも一つであり、
Ｆはフッ素であり、
Ｍは１３族元素（Ａｌ、Ｂ）、１４族元素（Ｓｉ）及び１５族元素（Ｐ、Ａｓ、Ｓｂ）からなる群から選ばれるいずれか１つであり
Ｏは酸素であり、
Ｎは窒素である。
Ｙは炭素又は硫黄であり、Ｙが炭素である場合ｑは１であり、Ｙが硫黄である場合ｑは１又は２である。
Ｘは炭素又は硫黄であり、Ｘが炭素である場合ｒは１であり、Ｘが硫黄である場合ｒは１又は２である。
Ｒ^１は炭素数１〜１０の環やヘテロ原子やハロゲン原子を有していてもよい炭化水素基（炭素数が３以上の場合にあっては、分岐鎖あるいは環状構造のものも使用できる）、又は−Ｎ（Ｒ^２）−を表す。このとき、Ｒ^２は水素、アルカリ金属、炭素数１〜１０の環やヘテロ原子やハロゲン原子を有していてもよい炭化水素基を表す。炭素数が３以上の場合にあっては、Ｒ^２は分岐鎖あるいは環状構造をとることもできる。
Ｒ^４、Ｒ^５はそれぞれ独立で炭素数１〜１０の環やヘテロ原子やハロゲン原子を有していてもよい炭化水素基であり、炭素数が３以上の場合にあっては、分岐鎖あるいは環状構造のものも使用できる。また、下記一般式［５］の様にお互いを含む環状構造を有しても良い。

ｃは０又は１であり、ｎが１の場合、ｃは０（ｃが０のときＤは存在しない）であり、ｎが２の場合、ｃは１となる。
ｏは２又は４、ｎは１又は２、ｐは０又は１、ｑは１又は２、ｒは１又は２、ｓは０又は１である。ｐが０の場合、Ｙ−Ｘ間に直接結合を形成する。
ｓが０の場合、Ｎ（Ｒ^４）（Ｒ^５）とＲ^１は直接結合し、その際は下記の［６］〜［９］のような構造をとることもできる。直接結合が二重結合となる［７］、［９］の場合、Ｒ^５は存在しない。また［８］の様に二重結合が環の外に出た構造を取ることも出来る。この場合のＲ^６、Ｒ^７はそれぞれ独立で水素、又は炭素数１〜１０の環やヘテロ原子やハロゲン原子を有していてもよい炭化水素基であり、炭素数が３以上の場合にあっては、分岐鎖あるいは環状構造のものも使用できる。）

上記イミドアニオンを有する塩としては、下記一般式［１０］〜［１６］で示される化合物や、（ＣＦ_２）_２（ＳＯ_２）_２Ｎ⁻、（ＣＦ_２）_３（ＳＯ_２）_２Ｎ⁻等の環状アルキレン鎖含有アニオンを有する塩を例示することができる。

［一般式［１０］〜［１１］及び［１３］〜［１５］中、Ｒ^８〜Ｒ^１１はそれぞれ互いに独立して、フッ素原子、炭素数が１〜１０の直鎖あるいは分岐状のアルコキシ基、炭素数が２〜１０のアルケニルオキシ基、炭素数が２〜１０のアルキニルオキシ基、炭素数が３〜１０の、シクロアルコキシ基、シクロアルケニルオキシ基、及び、炭素数が６〜１０のアリールオキシ基から選ばれる有機基であり、その有機基中にフッ素原子、酸素原子、不飽和結合が存在することもできる。一般式［１１］、［１２］、［１５］及び［１６］中、Ｘ^２及びＸ^３はそれぞれ互いに独立して、フッ素原子、炭素数が１〜１０の直鎖あるいは分岐状のアルキル基、炭素数が２〜１０のアルケニル基、炭素数が２〜１０のアルキニル基、炭素数が３〜１０の、シクロアルキル基、シクロアルケニル基、炭素数が６〜１０のアリール基、炭素数が１〜１０の直鎖あるいは分岐状のアルコキシ基、炭素数が２〜１０のアルケニルオキシ基、炭素数が２〜１０のアルキニルオキシ基、炭素数が３〜１０の、シクロアルコキシ基、シクロアルケニルオキシ基、及び、炭素数が６〜１０のアリールオキシ基から選ばれる有機基であり、その有機基中にフッ素原子、酸素原子、不飽和結合が存在することもできる。また、一般式［１０］〜［１６］中には少なくとも一つのＰ−Ｆ結合及び／又はＳ−Ｆ結合を含む。Ｍ^２、Ｍ^３はそれぞれ互いに独立して、プロトン、金属カチオン又はオニウムカチオンである。］
上記Ｓｉ含有化合物としては、下記一般式［１７］で示される少なくとも１種の化合物や、ヘキサメチルシロキサン、１，３−ジビニルテトラメチルジシロキサン、（ビスヘキサフルオロイソプロポキシ）（ジメチル）（ジビニル）ジシロキサン、テトラメチルシラン、トリメチルビニルシラン、ビニルジメチルフルオロシラン、ジビニルメチルフルオロシラン等を例示することができる。
Ｓｉ（Ｒ^１２）_ｘ（Ｒ^１３）_４−ｘ ［１７］
［一般式［１７］中、Ｒ^１２はそれぞれ互いに独立して炭素−炭素不飽和結合を有する基を表す。Ｒ^１３はそれぞれ互いに独立して、フッ素原子、アルキル基、アルコキシ基、アルケニル基、アルケニルオキシ基、アルキニル基、アルキニルオキシ基、アリール基、及びアリールオキシ基からなる群から選ばれる基を示し、これらの基はフッ素原子及び／又は酸素原子を有していても良い。ｘは２〜４である。］
上記硫酸エステル化合物としては、下記一般式［１８］、［１９］、及び［２０］で示される環状スルホン酸化合物や、２，２−ジオキシド−１，２−オキサチオラン−４−イル、１，３−プロパンスルトン、１，３−ブタンスルトン、１，４−ブタンスルトン等を例示することができる。

（式［１８］中、Ｏは酸素原子、Ｓは硫黄原子、ｎ^２は１以上３以下の整数である。また、Ｒ^１４、Ｒ^１５、Ｒ^１６、Ｒ^１７は、それぞれ独立して水素原子、置換若しくは無置換の炭素数１以上５以下のアルキル基、又は置換若しくは無置換の炭素数１以上４以下のフルオロアルキル基である。）

（式［１９］中、Ｏは酸素原子、Ｓは硫黄原子、ｎ^３は０以上４以下の整数であり、Ｒ^１８、Ｒ^１９は、それぞれ独立して水素原子、ハロゲン原子、又は置換若しくは無置換の炭素数１以上５以下のアルキル基であり、Ｒ^２０、Ｒ^２１は、それぞれ独立して水素原子、ハロゲン原子、置換若しくは無置換の炭素数１〜５のアルキル基、又は置換若しくは無置換の炭素数１以上４以下のフルオロアルキル基であり、ｎ^４は０以上４以下の整数である。）

（式［２０］中、Ｏは酸素原子、Ｓは硫黄原子、ｎ^５は０〜３の整数であり、Ｒ^２２、Ｒ^２３は、それぞれ独立して水素原子、ハロゲン原子、置換若しくは無置換の炭素数１以上５以下のアルキル基、又は置換若しくは無置換の炭素数１以上４以下のフルオロアルキル基である。）
上記リン酸エステル化合物としては、リン酸トリメチル、リン酸トリブチル、及びリン酸トリオクチル、リン酸トリス（２，２，２−トリフルオロエチル）、モノフルオロプロパギロキシリン酸-五フッ化リン酸リチウム等を例示することができる。
上記環状カーボネート化合物としては、下記一般式［２１］で示される環状カーボネート化合物や、ジメチルビニレンカーボネート等を例示することができる。

（式［２１］中、Ｏは酸素原子、Ａは炭素数１０以下の、不飽和結合や環状構造やハロゲンを有してもよい炭化水素であり、Ｂは炭素数１０以下の、不飽和結合や環状構造やハロゲンを有してもよい炭化水素である。なお、Ａ−Ｂ間に二重結合を有してもよい。）
上記イソシアネート化合物としては、ヘキサメチレンジイソシアネート、オクタメチレンジイソシアネート、２−イソシアナトエチルアクリレート、２−イソシアナトエチルメタクリレート等を例示することができる。
上記環状アセタール化合物としては、１，３−ジオキソラン、１，３−ジオキサン、１，３，５−トリオキサン等を例示することができる。
上記環状酸無水物としては、無水コハク酸、無水マレイン酸等を例示することができる。
上記環状ホスファゼン化合物としては、メトキシペンタフルオロシクロトリホスファゼン、エトキシペンタフルオロシクロトリホスファゼン、フェノキシペンタフルオロシクロトリホスファゼン、ジエトキシペンタフルオロシクロトリホスファゼン、エトキシヘプタフルオロシクロテトラホスファゼン等を例示することができる。
上記芳香族化合物としては、シクロヘキシルベンゼン、ビフェニル、ｔｅｒｔ−ブチルベンゼン、４−フルオロビフェニル、フルオロベンゼン、２，４−ジフルオロベンゼン、ジフルオロアニソール等を例示することができる。
なお、その他の成分として上記で挙げた添加剤の一部は（ＩＶ）溶質と重複するものがあるが、そのような化合物は、（ＩＶ）溶質のように比較的多く含有させて用いることもできるし、添加剤（その他の成分）のように比較的少なく含有させて用いることもできる。 [Other ingredients]
Furthermore, as long as the gist of the present invention is not impaired, an additive generally used in the nonaqueous electrolytic solution of the present invention may be added at an arbitrary ratio. Specific examples include compounds having an overcharge preventing effect, a negative electrode film forming effect, and a positive electrode protecting effect, such as cyclohexylbenzene, biphenyl, t-butylbenzene, vinylethylene carbonate, and difluoroanisole. Moreover, it is also possible to use a non-aqueous electrolyte by quasi-solidifying it with a gelling agent or a cross-linked polymer as in the case of use in a non-aqueous electrolyte secondary battery called a polymer battery.
In addition, a compound corresponding to the monomer of the additive for non-aqueous electrolyte of the present invention may also be present in the non-aqueous electrolyte. At this time, present in the electrolyte solution,
A total amount (M) of monomers corresponding to the repeating unit represented by the general formula [1],
The total amount (P) (monomer conversion) of the non-aqueous electrolyte additive is
(M) / (P) = 0-0.05 (mass ratio)
It is preferable because it leads to an improvement in rate characteristics. (M) / (P) = 0 to 0.02 is more preferable, and (M) / (P) = 0 is still more preferable. Incidentally, the nonaqueous electrolytic solution, the total amount of the monomer (M), and the total amount of nonaqueous electrolyte solution additive (P) (monomer conversion) is calculated from ^{the 1 H-NMR} measurement results.
Further, the non-aqueous electrolyte of the present invention is
Ionic complex having cyclic structure, salt having imide anion, Si-containing compound, sulfate ester compound, phosphate ester compound, cyclic carbonate compound, isocyanate compound, cyclic acetal compound, cyclic acid anhydride, cyclic phosphazene compound, aromatic compound It is preferable to contain at least one compound selected from the group consisting of (hereinafter collectively referred to as “second additive”).
It is preferable that the content of (II) is 0.03 to 14.0% by mass relative to 100% by mass of the total amount of (I), (II), (III), (IV) and the second additive, 0.07-12.0 mass% is more preferable.
The total amount of (IV) with respect to 100% by mass of the total amount of (I), (II), (III), (IV) and the second additive is not particularly limited, but the lower limit is 0.5 mol / L or more, Preferably it is 0.7 mol / L or more, more preferably 0.9 mol / L or more, and the upper limit is 5.0 mol / L or less, preferably 4.0 mol / L or less, more preferably 2.0 mol / L or less. Range.
The total amount of the second additive with respect to the total amount of 100% by mass of (I), (II), (III), (IV) and the second additive is not particularly limited, but is 0.01 to 20.0 mass. % Is preferable, and 0.05 to 10.0% by mass is more preferable.
Examples of the ionic complex having the cyclic structure include compounds represented by the following general formulas [2] to [4].

(In general formula [2],
A is at least one selected from the group consisting of metal ions, protons and onium ions,
F is fluorine,
M is at least one selected from the group consisting of a group 13 element (Al, B), a group 14 element (Si), and a group 15 element (P, As, Sb);
O is oxygen,
S is sulfur.
R ¹ is a hydrocarbon group which may have a ring having 1 to 10 carbon atoms, a hetero atom or a halogen atom (in the case of 3 or more carbon atoms, a branched chain or cyclic structure can be used) , or -N ^{(R 2)} - represents a. At this time, R ² represents hydrogen, an alkali metal, a hydrocarbon group which may have a ring having 1 to 10 carbon atoms, a hetero atom, or a halogen atom. When the number of carbon atoms is 3 or more, R ² can also take a branched chain or a cyclic structure.
Y is carbon or sulfur. R is 1 when Y is carbon. When Y is sulfur, r is 1 or 2.
a is 1 or 2, o is 2 or 4, n is 1 or 2, p is 0 or 1, q is 1 or 2, and r is 0, 1 or 2. When p is 0, a direct bond is formed between S and Y. )

(In general formula [3],
A is at least one selected from the group consisting of metal ions, protons and onium ions,
F is fluorine,
M is at least one selected from the group consisting of group 13 elements (Al, B), group 14 elements (Si), and group 15 elements (P, As, Sb);
O is oxygen,
N is nitrogen.
Y is carbon or sulfur. When Y is carbon, q is 1. When Y is sulfur, q is 1 or 2.
R ¹ is a hydrocarbon group which may have a ring having 1 to 10 carbon atoms, a hetero atom or a halogen atom (in the case of 3 or more carbon atoms, a branched chain or cyclic structure can be used) , or -N ^{(R 2)} - represents a. At this time, R ² represents hydrogen, an alkali metal, a hydrocarbon group which may have a ring having 1 to 10 carbon atoms, a hetero atom, or a halogen atom. When the number of carbon atoms is 3 or more, R ² can also take a branched chain or a cyclic structure.
R ³ is hydrogen, a hydrocarbon group which may have a ring having 1 to 10 carbon atoms, a hetero atom or a halogen atom (if the number of carbon atoms is 3 or more, a branched chain or cyclic structure is also used. Or -N (R ² )-. At this time, R ² represents hydrogen, an alkali metal, a hydrocarbon group which may have a ring having 1 to 10 carbon atoms, a hetero atom, or a halogen atom. When the number of carbon atoms is 3 or more, R ² can also take a branched chain or a cyclic structure.
a is 1 or 2, o is 2 or 4, n is 1 or 2, p is 0 or 1, q is 1 or 2, and r is 0 or 1. When p is 0, atoms located on both sides of R ¹ (that is, Y and a carbon atom) directly form a bond. When r is 0, a direct bond is formed between MN. )

(In general formula [4],
D represents halogen ion, hexafluorophosphate anion, tetrafluoroborate anion, bis (trifluoromethanesulfonyl) imide anion, bis (fluorosulfonyl) imide anion, (fluorosulfonyl) (trifluoromethanesulfonyl) imide anion, bis (difluorophospho Nyl) imide anion,
F is fluorine,
M is any one selected from the group consisting of Group 13 elements (Al, B), Group 14 elements (Si), and Group 15 elements (P, As, Sb), O is oxygen,
N is nitrogen.
Y is carbon or sulfur. When Y is carbon, q is 1. When Y is sulfur, q is 1 or 2.
X is carbon or sulfur, r is 1 when X is carbon, and r is 1 or 2 when X is sulfur.
R ¹ is a hydrocarbon group which may have a ring having 1 to 10 carbon atoms, a hetero atom or a halogen atom (in the case of 3 or more carbon atoms, a branched chain or cyclic structure can be used) , or -N ^{(R 2)} - represents a. At this time, R ² represents hydrogen, an alkali metal, a hydrocarbon group which may have a ring having 1 to 10 carbon atoms, a hetero atom, or a halogen atom. When the number of carbon atoms is 3 or more, R ² can also take a branched chain or a cyclic structure.
R ⁴ and R ⁵ are each independently a hydrocarbon group which may have a ring having 1 to 10 carbon atoms, a hetero atom or a halogen atom, and in the case where the number of carbon atoms is 3 or more, a branched chain or An annular structure can also be used. Moreover, you may have a cyclic structure containing each other like following General formula [5].

When c is 0 or 1, when n is 1, c is 0 (D is not present when c is 0), and when n is 2, c is 1.
o is 2 or 4, n is 1 or 2, p is 0 or 1, q is 1 or 2, r is 1 or 2, and s is 0 or 1. When p is 0, a direct bond is formed between Y and X.
When s is 0, N (R ⁴ ) (R ⁵ ) and R ¹ are directly bonded, and in this case, the following structures [6] to [9] can be taken. In the case of [7] and [9] in which the direct bond is a double bond, R ⁵ does not exist. Moreover, it can also take the structure where the double bond went out of the ring like [8]. In this case, R ⁶ and R ⁷ are each independently hydrogen, or a hydrocarbon group that may have a ring having 1 to 10 carbon atoms, a hetero atom, or a halogen atom. For example, a branched chain or cyclic structure can be used. )

Examples of the salt having the imide anion include compounds represented by the following general formulas [10] to [16], (CF ₂ ) ₂ (SO ₂ ) ₂ N ⁻ , (CF ₂ ) ₃ (SO ₂ ) ₂ N ^−. Examples thereof include salts having a cyclic alkylene chain-containing anion such as.

[In the general formulas [10] to [11] and [13] to [15], R ^{8 to} R ¹¹ are each independently a fluorine atom or a linear or branched alkoxy group having 1 to 10 carbon atoms. , An alkenyloxy group having 2 to 10 carbon atoms, an alkynyloxy group having 2 to 10 carbon atoms, a cycloalkoxy group, a cycloalkenyloxy group having 3 to 10 carbon atoms, and an aryl having 6 to 10 carbon atoms It is an organic group selected from oxy groups, and fluorine atoms, oxygen atoms, and unsaturated bonds may be present in the organic groups. In the general formulas [11], [12], [15] and [16], X ² and X ³ are each independently a fluorine atom, a linear or branched alkyl group having 1 to 10 carbon atoms, C2-C10 alkenyl group, C2-C10 alkynyl group, C3-C10 cycloalkyl group, cycloalkenyl group, C6-C10 aryl group, C1-C1 -10 linear or branched alkoxy group, alkenyloxy group having 2 to 10 carbon atoms, alkynyloxy group having 2 to 10 carbon atoms, cycloalkoxy group and cycloalkenyloxy group having 3 to 10 carbon atoms And an organic group selected from aryloxy groups having 6 to 10 carbon atoms, and a fluorine atom, an oxygen atom, and an unsaturated bond may be present in the organic group. Further, the general formulas [10] to [16] include at least one PF bond and / or SF bond. M ² and M ³ are each independently a proton, a metal cation or an onium cation. ]
Examples of the Si-containing compound include at least one compound represented by the following general formula [17], hexamethylsiloxane, 1,3-divinyltetramethyldisiloxane, (bishexafluoroisopropoxy) (dimethyl) (divinyl) Examples include disiloxane, tetramethylsilane, trimethylvinylsilane, vinyldimethylfluorosilane, divinylmethylfluorosilane, and the like.
Si (R ¹² ) _x (R ¹³ ) _4-x [17]
[In General Formula [17], R ¹² each independently represents a group having a carbon-carbon unsaturated bond. R ¹³ each independently represents a group selected from the group consisting of a fluorine atom, an alkyl group, an alkoxy group, an alkenyl group, an alkenyloxy group, an alkynyl group, an alkynyloxy group, an aryl group, and an aryloxy group. The group may have a fluorine atom and / or an oxygen atom. x is 2-4. ]
Examples of the sulfate ester compounds include cyclic sulfonic acid compounds represented by the following general formulas [18], [19], and [20], 2,2-dioxide-1,2-oxathiolan-4-yl, 1,3 -Propane sultone, 1,3-butane sultone, 1,4-butane sultone and the like can be exemplified.

(In the formula [18], O is an oxygen atom, S is a sulfur atom, n ² is an integer of 1 to 3, and R ¹⁴ , R ¹⁵ , R ¹⁶ and R ¹⁷ are each independently a hydrogen atom. A substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, or a substituted or unsubstituted fluoroalkyl group having 1 to 4 carbon atoms.)

(In the formula [19], O is an oxygen atom, S is a sulfur atom, n ³ is an integer of 0 or more and 4 or less, and R ¹⁸ and R ¹⁹ are each independently a hydrogen atom, a halogen atom, or a substituted or non-substituted group. A substituted alkyl group having 1 to 5 carbon atoms, and R ²⁰ and R ²¹ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, or a substituted or unsubstituted group. And the number of carbon atoms is a fluoroalkyl group having 1 to 4 carbon atoms, and n ⁴ is an integer of 0 to 4 inclusive)

(In the formula [20], O is an oxygen atom, S is a sulfur atom, n ⁵ is an integer of 0 to 3, and R ²² and R ²³ are each independently a hydrogen atom, a halogen atom, a substituted or unsubstituted atom. C 1 -C 5 alkyl group or substituted or unsubstituted C 1 -C 4 fluoroalkyl group.)
Examples of the phosphoric acid ester compound include trimethyl phosphate, tributyl phosphate, trioctyl phosphate, tris (2,2,2-trifluoroethyl) phosphate, monofluoropropargyloxyphosphate-lithium pentafluorophosphate Etc. can be illustrated.
Examples of the cyclic carbonate compound include a cyclic carbonate compound represented by the following general formula [21], dimethyl vinylene carbonate, and the like.

(In the formula [21], O is an oxygen atom, A is a hydrocarbon having 10 or less carbon atoms and may have an unsaturated bond, cyclic structure or halogen, and B is an unsaturated bond having 10 or less carbon atoms. And a hydrocarbon which may have a cyclic structure and halogen, and may have a double bond between A and B.)
Examples of the isocyanate compound include hexamethylene diisocyanate, octamethylene diisocyanate, 2-isocyanatoethyl acrylate, and 2-isocyanatoethyl methacrylate.
Examples of the cyclic acetal compound include 1,3-dioxolane, 1,3-dioxane, 1,3,5-trioxane and the like.
Examples of the cyclic acid anhydride include succinic anhydride and maleic anhydride.
Examples of the cyclic phosphazene compound include methoxypentafluorocyclotriphosphazene, ethoxypentafluorocyclotriphosphazene, phenoxypentafluorocyclotriphosphazene, diethoxypentafluorocyclotriphosphazene, ethoxyheptafluorocyclotetraphosphazene, and the like.
Examples of the aromatic compound include cyclohexylbenzene, biphenyl, tert-butylbenzene, 4-fluorobiphenyl, fluorobenzene, 2,4-difluorobenzene, difluoroanisole and the like.
In addition, some of the additives listed above as other components may overlap with the (IV) solute, but such a compound may be used in a relatively large amount like the (IV) solute. It can also be used in a relatively small amount such as an additive (other components).

3. Non-aqueous electrolyte secondary battery Non-aqueous electrolyte, negative electrode material capable of reversibly inserting and removing alkali metal ions such as lithium ions and sodium ions, or alkaline earth metal ions, lithium ions and sodium An electrochemical device using a positive electrode material into which alkali metal ions such as ions or alkaline earth metal ions can be reversibly inserted and removed is called a non-aqueous electrolyte secondary battery.
The negative electrode is not particularly limited, but a material capable of reversibly inserting and desorbing alkali metal ions such as lithium ions and sodium ions or alkaline earth metal ions is used, and the positive electrode is not particularly limited. However, materials in which alkali metal ions such as lithium ions and sodium ions or alkaline earth metal ions can be reversibly inserted and removed are used.

  For example, when the cation is lithium, the negative electrode material is lithium metal, alloys of lithium and other metals, intermetallic compounds, various carbon materials capable of inserting and extracting lithium, metal oxides, metal nitrides, activated carbon A conductive polymer or the like is used. Examples of the carbon material include graphitizable carbon, non-graphitizable carbon (also referred to as hard carbon) having a (002) plane spacing of 0.37 nm or more, and a (002) plane spacing of 0. Examples include graphite having a thickness of 37 nm or less, and the latter is made of artificial graphite, natural graphite, or the like.

For example, when the cation is lithium, lithium-containing transition metal composite oxides such as LiCoO ₂ , LiNiO ₂ , LiMnO ₂ and LiMn ₂ O ₄ as the positive electrode material, Co, Mn, Ni, etc. of these lithium-containing transition metal composite oxides Those in which a plurality of transition metals are mixed (for example, LiNi _0.5 Mn _1.5 O ₄ etc.), and those in which some of the transition metals of these lithium-containing transition metal composite oxides are replaced with metals other than transition metals , LiFePO _4, LiCoPO _4, phosphoric acid compound of a transition metal such as LiMnPO ₄ called _olivine, oxides such as _{TiO 2, V 2 O 5,} MoO 3, TiS 2, sulfides such as FeS, or polyacetylene, poly para Conductive polymers such as phenylene, polyaniline, and polypyrrole, activated carbon, and polymers that generate radicals Carbon materials are used.

  In the positive electrode material and the negative electrode material, acetylene black, ketjen black, carbon fiber, or graphite is added as a conductive material, and polytetrafluoroethylene, polyvinylidene fluoride, or SBR resin is added as a binder, and further molded into a sheet shape. The electrode sheet made can be used.

  As a separator for preventing contact between the positive electrode and the negative electrode, a nonwoven fabric or a porous sheet made of polypropylene, polyethylene, paper, glass fiber or the like is used.

  From the above elements, an electrochemical device having a shape such as a coin shape, a cylindrical shape, a square shape, or an aluminum laminate sheet shape is assembled.

In addition, non-aqueous electrolyte secondary battery is
A non-aqueous electrolyte secondary battery including (a) the above non-aqueous electrolyte, (b) a positive electrode, (c) a negative electrode, and (d) a separator as described below may be used.
[(A) Positive electrode]
(A) The positive electrode preferably contains at least one oxide and / or polyanion compound as a positive electrode active material.
[Positive electrode active material]
In the case of a lithium ion secondary battery in which the cation in the non-aqueous electrolyte is mainly lithium, (a) the positive electrode active material constituting the positive electrode is not particularly limited as long as it is various materials that can be charged and discharged. For example, (A) a lithium transition metal composite oxide containing at least one metal selected from nickel, manganese and cobalt and having a layered structure, (B) a lithium manganese composite oxide having a spinel structure, (C) What contains at least 1 sort (s) from the lithium containing olivine type | mold phosphate and the lithium excess layered transition metal oxide which has (D) layered rock salt type structure is mentioned.
((A) lithium transition metal composite oxide)
Cathode active material (A) Examples of lithium transition metal composite oxides containing at least one metal selected from nickel, manganese and cobalt and having a layered structure include lithium-cobalt composite oxides and lithium-nickel composite oxides. Lithium / nickel / cobalt composite oxide, lithium / nickel / cobalt / aluminum composite oxide, lithium / cobalt / manganese composite oxide, lithium / nickel / manganese composite oxide, lithium / nickel / manganese / cobalt composite oxide Etc. In addition, some of the transition metal atoms that are the main components of these lithium transition metal composite oxides are Al, Ti, V, Cr, Fe, Cu, Zn, Mg, Ga, Zr, Si, B, Ba, Y, Sn. Those substituted with other elements such as may also be used.
Specific examples of the lithium-cobalt composite oxide and the lithium-nickel composite oxide include LiCoO ₂ , LiNiO ₂ , lithium cobalt oxide to which a different element such as Mg, Zr, Al, and Ti is added (LiCo _0.98 Mg _{0. 01} Zr _0.01 O ₂ , LiCo _0.98 Mg _0.01 Al _0.01 O ₂ , LiCo _0.975 Mg _0.01 Zr _0.005 Al _0.01 O ₂ ), WO 2014/034043 You may use the lithium cobaltate etc. which fixed the rare earth compound to the surface of description. Further, as described in Japanese Patent Application Laid-Open No. 2002-151077, etc., a part of the particle surface of LiCoO ₂ particle powder coated with aluminum oxide may be used.
The lithium / nickel / cobalt composite oxide and the lithium / nickel / cobalt / aluminum composite oxide are represented by formula (1-1).
Li _a Ni _1-bc Co _b M ¹ _c O ₂ (1-1)
In formula (1-1), M ¹ is at least one element selected from the group consisting of Al, Fe, Mg, Zr, Ti, and B, a is 0.9 ≦ a ≦ 1.2, b , C satisfy the conditions of 0.1 ≦ b ≦ 0.3 and 0 ≦ c ≦ 0.1.
These can be prepared, for example, according to the production method described in JP2009-137835A. Specifically, LiNi _0.8 Co _0.2 O ₂ , LiNi _0.85 Co _0.10 Al _0.05 O ₂ , LiNi _0.87 Co _0.10 Al _0.03 O ₂ , LiNi _0.6 Examples include Co _0.3 Al _0.1 O ₂ .
Specific examples of the lithium / cobalt / manganese composite oxide and the lithium / nickel / manganese composite oxide include LiNi _0.5 Mn _0.5 O ₂ and LiCo _0.5 Mn _0.5 O ₂ .
Examples of the lithium / nickel / manganese / cobalt composite oxide include a lithium-containing composite oxide represented by the general formula (1-2).
_{Li d Ni e Mn f Co g} M 2 h O 2 (1-2)
In formula (1-2), M ² is at least one element selected from the group consisting of Al, Fe, Mg, Zr, Ti, B, and Sn, and d is 0.9 ≦ d ≦ 1.2. , E, f, g, and h satisfy the conditions of e + f + g + h = 1, 0 ≦ e ≦ 0.7, 0 ≦ f ≦ 0.5, 0 ≦ g ≦ 0.5, and h ≧ 0.
The lithium / nickel / manganese / cobalt composite oxide contains manganese in the range represented by the general formula (1-2) in order to enhance the structural stability and improve the safety at a high temperature in the lithium secondary battery. In particular, it is more preferable to further contain cobalt in the range represented by the general formula (1-2) in order to enhance the high rate characteristics of the lithium ion secondary battery.
Specifically, for example, Li [Ni _1/3 Mn _1/3 Co _1/3 ] O ₂ , Li [Ni _0.45 Mn _0.35 Co _0.2 ] having a charge / discharge region of 4.3 V or higher. O ₂ , Li [Ni _0.5 Mn _0.3 Co _0.2 ] O ₂ , Li [Ni _0.6 Mn _0.2 Co _0.2 ] O ₂ , Li [Ni _0.49 Mn _0.3 Co _0.2 Zr _0.01 ] O ₂ , Li [Ni _0.49 Mn _0.3 Co _0.2 Mg _0.01 ] O _{2 and the} like.
((B) lithium manganese composite oxide having spinel structure)
As a lithium manganese complex oxide which has a positive electrode active material (B) spinel structure, the spinel type lithium manganese complex oxide shown by General formula (1-3) is mentioned, for example.
^{_{Li j (Mn 2-k M}} 3 k) O 4 (1-3)
In Formula (1-3), M ³ is at least one metal element selected from the group consisting of Ni, Co, Fe, Mg, Cr, Cu, Al, and Ti, and j is 1.05 ≦ j ≦ 1. 15 and k is 0 ≦ k ≦ 0.20.
Specifically, for example, LiMn ₂ O ₄ , LiMn _1.95 Al _0.05 O ₄ , LiMn _1.9 Al _0.1 O ₄ , LiMn _1.9 Ni _0.1 O ₄ , LiMn _1.5 Ni _0.5 O ₄ etc. are mentioned.
((C) Lithium-containing olivine-type phosphate)
As a positive electrode active material (C) lithium containing olivine type | mold phosphate, what is shown by General formula (1-4) is mentioned, for example.
LiFe _1-n M ⁴ _n PO ₄ (1-4)
In Formula (1-4), M ⁴ is at least one selected from Co, Ni, Mn, Cu, Zn, Nb, Mg, Al, Ti, W, Zr, and Cd, and n is 0 ≦ n ≦ 1.
Specifically, for example, LiFePO ₄ , LiCoPO ₄ , LiNiPO ₄ , LiMnPO _{4 and the} like can be mentioned, among which LiFePO ₄ and / or LiMnPO ₄ are preferable.
((D) lithium-excess layered transition metal oxide)
Examples of the lithium-excess layered transition metal oxide having a positive electrode active material (D) layered rock salt structure include those represented by general formula (1-5).
xLiM ⁵ O _2. (1-x) Li ₂ M ⁶ O ₃ (1-5)
In formula (1-5), x is a number satisfying 0 <x <1, M ⁵ is at least one metal element having an average oxidation number of 3 ⁺ , and M ⁶ is an average oxidation the number is at least one or more metal elements 4 ^+. In formula (1-5), M ⁵ is preferably one or more metal elements selected from trivalent Mn, Ni, Co, Fe, V, and Cr. The average oxidation number may be trivalent with an amount of metal.
In formula (1-5), M ⁶ is preferably one or more metal elements selected from Mn, Zr, and Ti. Specifically, 0.5 [LiNi _0.5 Mn _0.5 O ₂ ] · 0.5 [Li ₂ MnO ₃ ], 0.5 [LiNi _1/3 Co _1/3 Mn _1/3 O ₂ ] 0.5 [Li ₂ MnO ₃ ], 0.5 [LiNi _0.375 Co _0.25 Mn _0.375 O ₂ ], 0.5 [Li ₂ MnO ₃ ], 0.5 [LiNi _0.375 Co _0.125 Fe _0.125 Mn _0.375 O ₂ ] · 0.5 [Li ₂ MnO ₃ ], 0.45 [LiNi _0.375 Co _0.25 Mn _0.375 O ₂ ] · 0.10 [Li ₂ TiO ₃ ] · 0.45 [Li ₂ MnO ₃ ] and the like.
It is known that the positive electrode active material (D) represented by the general formula (1-5) expresses a high capacity at a high voltage charge of 4.4 V (Li standard) or more (for example, US Pat. , 135, 252).
These positive electrode active materials can be prepared according to, for example, the production methods described in JP 2008-270201 A, WO 2013/118661, JP 2013-030284 A, and the like.
As the positive electrode active material, the (A) ~ may be contained as a main component at least one selected from (D), Included in otherwise example _{FeS 2, TiS 2, V 2} O 5 , Transition element chalcogenides such as MoO ₃ and MoS ₂ , or conductive polymers such as polyacetylene, polyparaphenylene, polyaniline, and polypyrrole, activated carbon, polymers that generate radicals, and carbon materials.
[Positive electrode current collector]
(A) The positive electrode has a positive electrode current collector. As the positive electrode current collector, for example, aluminum, stainless steel, nickel, titanium, or an alloy thereof can be used.
[Positive electrode active material layer]
(A) In the positive electrode, for example, a positive electrode active material layer is formed on at least one surface of the positive electrode current collector. A positive electrode active material layer is comprised by the above-mentioned positive electrode active material, a binder, and a electrically conductive agent as needed, for example.
Examples of the binder include polytetrafluoroethylene, polyvinylidene fluoride, or styrene butadiene rubber (SBR) resin.
As the conductive agent, for example, a carbon material such as acetylene black, ketjen black, carbon fiber, or graphite (granular graphite or flake graphite) can be used. In the positive electrode, it is preferable to use acetylene black or ketjen black having low crystallinity.
[(C) Negative electrode]
(C) The negative electrode preferably contains at least one negative electrode active material.
[Negative electrode active material]
In the case of a lithium ion secondary battery in which the cation in the non-aqueous electrolyte is mainly lithium, (c) as the negative electrode active material constituting the negative electrode, lithium ion can be doped / dedoped. For example, (E) a carbon material in which the d value of the lattice plane (002 plane) in X-ray diffraction is 0.340 nm or less, and (F) carbon whose d value of the lattice plane (002 plane) in X-ray diffraction exceeds 0.340 nm A material, (G) an oxide of one or more metals selected from Si, Sn, Al, (H) one or more metals selected from Si, Sn, Al, alloys containing these metals, or these metals or alloys; Examples include an alloy with lithium and (I) at least one selected from lithium titanium oxide. These negative electrode active materials can be used individually by 1 type, and can also be used in combination of 2 or more type.
((E) Carbon material whose d-value on the lattice plane (002 plane) in X-ray diffraction is 0.340 nm or less)
Examples of the carbon material having a d value of 0.340 nm or less in the lattice plane (002 plane) in the negative electrode active material (E) X-ray diffraction include pyrolytic carbons and cokes (for example, pitch coke, needle coke, and petroleum coke). , Graphites, organic polymer compound fired bodies (for example, those obtained by firing and carbonizing a phenol resin, furan resin, etc.), carbon fibers, activated carbon, and the like. These may be graphitized. The carbon material has a (002) plane spacing (d002) of 0.340 nm or less measured by an X-ray diffraction method. Among them, graphite having a true density of 1.70 g / cm ³ or more, or A highly crystalline carbon material having close properties is preferred.
((F) Carbon material whose d value of the lattice plane (002 plane) in X-ray diffraction exceeds 0.340 nm)
As the carbon material in which the d value of the lattice plane (002 plane) in the negative electrode active material (F) X-ray diffraction exceeds 0.340 nm, amorphous carbon can be cited, which is obtained by heat treatment at a high temperature of 2000 ° C. or higher. Is a carbon material whose stacking order hardly changes. Examples thereof include non-graphitizable carbon (hard carbon), mesocarbon microbeads (MCMB) baked at 1500 ° C. or less, and mesopage bitch carbon fiber (MCF). A typical example is Carbotron (registered trademark) P manufactured by Kureha Co., Ltd.
((G) One or more metal oxides selected from Si, Sn, and Al)
Negative electrode active material (G) One or more metal oxides selected from Si, Sn, and Al can be doped / dedoped with lithium ions, such as silicon oxide and tin oxide. .
There is SiO _x having a structure in which ultrafine particles of Si are dispersed in SiO ₂ . When this material is used as the negative electrode active material, since Si that reacts with Li is ultrafine particles, charging and discharging are performed smoothly, while the SiO _x particles having the above structure itself have a small surface area. The coating properties and the adhesion of the negative electrode mixture layer to the current collector when the composition (paste) is used to form the film are also good.
Since SiO _x large volume change during charge and discharge, SiO _x and above the negative electrode active material negative active material with high capacity by combining a good charge-discharge cycle characteristics at a specific ratio and a graphite (E) And both.
((H) one or more metals selected from Si, Sn, Al, alloys containing these metals, or alloys of these metals or alloys and lithium)
Negative electrode active material (H) One or more metals selected from Si, Sn, Al, alloys containing these metals, or alloys of these metals or alloys and lithium include, for example, metals such as silicon, tin, and aluminum, and silicon alloys , Tin alloys, aluminum alloys, and the like, and materials in which these metals and alloys are alloyed with lithium during charge and discharge can also be used.
Specific examples of these include, as described in WO 2004/100343 and JP-A-2008-016424, for example, simple metals (eg, powders) such as silicon (Si) and tin (Sn), and the metal alloys , A compound containing the metal, an alloy containing tin (Sn) and cobalt (Co) in the metal, and the like. When the metal is used for an electrode, a high charge capacity can be expressed, and the volume expansion / contraction associated with charge / discharge is relatively small, which is preferable. Moreover, when these metals are used for the negative electrode of a lithium ion secondary battery, they are known to exhibit a high charge capacity because they are alloyed with Li during charging, which is also preferable in this respect.
Further, for example, a negative electrode active material formed of silicon micro pillars having a submicron diameter, a negative electrode active material formed of fibers made of silicon, and the like described in WO 2004/042851 and WO 2007/083155 may be used. .
((I) lithium titanium oxide)
Examples of the negative electrode active material (I) lithium titanium oxide include lithium titanate having a spinel structure and lithium titanate having a ramsdellite structure.
Examples of lithium titanate having a spinel structure include Li _{4 + α} Ti ₅ O ₁₂ (α varies within a range of 0 ≦ α ≦ 3 due to a charge / discharge reaction). In addition, examples of lithium titanate having a ramsdellite structure include Li _{2 + β} Ti ₃ O ₇ (β varies within a range of 0 ≦ β ≦ 3 due to a charge / discharge reaction). These negative electrode active materials can be prepared according to the production methods described in, for example, JP-A No. 2007-018883 and JP-A No. 2009-176752.
For example, in the case of a sodium ion secondary battery in which the cation in the nonaqueous electrolytic solution is mainly sodium, hard carbon, oxides such as TiO ₂ , V ₂ O ₅ , and MoO ₃ are used as the negative electrode active material. For example, in the case of a sodium ion secondary battery in which the cation in the non-aqueous electrolyte is mainly sodium, a sodium-containing transition metal composite oxide such as NaFeO ₂ , NaCrO ₂ , NaNiO ₂ , NaMnO ₂ , and NaCoO ₂ as a positive electrode active material, Those containing transition metals such as Fe, Cr, Ni, Mn, Co, etc., of these sodium-containing transition metal composite oxides, some of the transition metals of these sodium-containing transition metal composite oxides other than other transition metals Substituted by transition metals, transition metal phosphate compounds such as Na ₂ FeP ₂ O ₇ , NaCo ₃ (PO ₄ ) ₂ P ₂ O ₇ , sulfides such as TiS ₂ and FeS ₂ , polyacetylene, polypara Conductive polymers such as phenylene, polyaniline, and polypyrrole, activated carbon, polymers that generate radicals, carbon Material and the like are used.
[Negative electrode current collector]
(C) The negative electrode has a negative electrode current collector. As the negative electrode current collector, for example, copper, stainless steel, nickel, titanium, or an alloy thereof can be used.
[Negative electrode active material layer]
(C) In the negative electrode, for example, a negative electrode active material layer is formed on at least one surface of the negative electrode current collector. A negative electrode active material layer is comprised by the above-mentioned negative electrode active material, a binder, and a electrically conductive agent as needed, for example.
Examples of the binder include polytetrafluoroethylene, polyvinylidene fluoride, or styrene butadiene rubber (SBR) resin.
As the conductive agent, for example, a carbon material such as acetylene black, ketjen black, carbon fiber, or graphite (granular graphite or flake graphite) can be used.
[Production method of electrode ((b) positive electrode and (c) negative electrode)]
The electrode is obtained, for example, by dispersing and kneading an active material, a binder, and, if necessary, a conductive agent in a solvent such as N-methyl-2-pyrrolidone (NMP) or water at a predetermined blending amount. The paste can be applied to a current collector and dried to form an active material layer. The obtained electrode is preferably compressed by a method such as a roll press to adjust the electrode to an appropriate density.
[(D) Separator]
The non-aqueous electrolyte battery includes (d) a separator. (A) As a separator for preventing the contact between the positive electrode and the (c) negative electrode, a nonwoven fabric or a porous sheet made of polyolefin such as polypropylene or polyethylene, cellulose, paper, glass fiber or the like is used. These films are preferably microporous so that the electrolyte can penetrate and ions can easily pass therethrough.
Examples of the polyolefin separator include a membrane that electrically insulates the positive electrode and the negative electrode and is permeable to lithium ions, such as a microporous polymer film such as a porous polyolefin film. As a specific example of the porous polyolefin film, for example, a porous polyethylene film alone or a porous polyethylene film and a porous polypropylene film may be overlapped and used as a multilayer film. Moreover, the composite film etc. of the porous polyethylene film and the polypropylene film are mentioned.
[Exterior body]
In configuring the non-aqueous electrolyte battery, as the exterior body of the non-aqueous electrolyte battery, for example, a metal can such as a coin shape, a cylindrical shape, or a square shape, or a laminate exterior body can be used. Examples of the metal can material include a steel plate subjected to nickel plating, a stainless steel plate, a stainless steel plate subjected to nickel plating, aluminum or an alloy thereof, nickel, and titanium.
As the laminate outer package, for example, an aluminum laminate film, a SUS laminate film, a laminate film made of silica-coated polypropylene, polyethylene, or the like can be used.
The configuration of the non-aqueous electrolyte battery according to the present embodiment is not particularly limited. For example, an electrode element in which a positive electrode and a negative electrode are opposed to each other and a non-aqueous electrolyte are included in an outer package. It can be set as a structure. The shape of the non-aqueous electrolyte battery is not particularly limited, but an electrochemical device having a shape such as a coin shape, a cylindrical shape, a square shape, or an aluminum laminate sheet type is assembled from the above elements.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention does not receive a restriction | limiting at all in these description.

(Preparation of non-aqueous electrolyte additive No. 1)
Vinylene carbonate (hereinafter referred to as “VC”) 10 g of N-methylpyrrolidone (hereinafter referred to as “NMP”) 40 mL solution in 2,2′-azobis (isobutyric acid) dimethyl (V601: manufactured by Wako Pure Chemical Industries, Ltd.) 4 0.5 g was added, and the operation of degassing under vacuum and introducing nitrogen was performed three times to make it in a nitrogen atmosphere, and then heated at 80 ° C. for 6 hours. The obtained reaction solution was poured into a large amount of methanol, and the polymer was reprecipitated using the methanol as a poor solvent. The precipitate was separated by filtration, and the polymer was recovered. The obtained polymer was dried at 60 ° C. under reduced pressure for 4 hours to remove the residual solvent, and additive No. for non-aqueous electrolyte solution was obtained. 1 was obtained in a yield of 38%.
Non-aqueous electrolyte additive No. 1 H-NMR measurement of ¹ was performed, and it was confirmed that all Rs in the above general formula [1] were H and a compound composed of an oligomer. In addition, non-aqueous electrolyte additive No. 1 GPC measurement was performed, and it was confirmed that the number average molecular weight in terms of polystyrene was 750. The results are shown in Table 1.

(Preparation of non-aqueous electrolyte additive No. 2)
4.0 g of 2,2′-azobis (isobutyric acid) dimethyl (V601: manufactured by Wako Pure Chemical Industries, Ltd.) is added to 40 g of NMP in 40 g of VC, and degassing and introducing nitrogen are performed three times under nitrogen. After the atmosphere, the mixture was heated at 80 ° C. for 6 hours. The obtained reaction solution was poured into a large amount of methanol, and the polymer was reprecipitated using the methanol as a poor solvent. The precipitate was separated by filtration, and the polymer was recovered. The obtained polymer was dried at 60 ° C. under reduced pressure for 4 hours to remove the residual solvent, and additive No. for non-aqueous electrolyte solution was obtained. 2 was obtained in a yield of 44%.
Non-aqueous electrolyte additive No. The ¹ H-NMR measurement of ^No. 2 was performed, and it was confirmed that all the Rs in the general formula [1] were H and that the compound was composed of an oligomer. In addition, non-aqueous electrolyte additive No. GPC measurement of No. 2 was performed, and it was confirmed that the number average molecular weight in terms of polystyrene was 1000. The results are shown in Table 1.

(Preparation of non-aqueous electrolyte additive No. 3)
4.0 g of 2,2′-azobis (isobutyric acid) dimethyl (V601: manufactured by Wako Pure Chemical Industries, Ltd.) is added to 20 g of NMP in 10 g of VC, and degassing under vacuum and introduction of nitrogen are performed three times. After the atmosphere, the mixture was heated at 80 ° C. for 6 hours. The obtained reaction solution was poured into a large amount of methanol, and the polymer was reprecipitated using the methanol as a poor solvent. The precipitate was separated by filtration, and the polymer was recovered. The obtained polymer was dried at 60 ° C. under reduced pressure for 4 hours to remove the residual solvent, and additive No. for non-aqueous electrolyte solution was obtained. 3 was obtained in a yield of 78%.
Non-aqueous electrolyte additive No. ^{1 was} subjected to ¹ H-NMR measurement, and it was confirmed that all Rs in the above general formula [1] were H and a compound composed of an oligomer. In addition, non-aqueous electrolyte additive No. 3 GPC measurement was performed, and it was confirmed that the number average molecular weight in terms of polystyrene was 2000. The results are shown in Table 1.

(Preparation of non-aqueous electrolyte additive No. 4)
Add 2.3 g of 2,2′-azobis (isobutyric acid) dimethyl (V601: manufactured by Wako Pure Chemical Industries, Ltd.) to 20 g of NMP in 10 g of VC, perform degassing under vacuum and introducing nitrogen three times. After the atmosphere, the mixture was heated at 80 ° C. for 6 hours. The obtained reaction solution was poured into a large amount of methanol, and the polymer was reprecipitated using the methanol as a poor solvent. The precipitate was separated by filtration, and the polymer was recovered. The obtained polymer was dried at 60 ° C. under reduced pressure for 4 hours to remove the residual solvent, and additive No. for non-aqueous electrolyte solution was obtained. 4 was obtained in a yield of 75%.
Non-aqueous electrolyte additive No. ^{1 was} subjected to ¹ H-NMR measurement, and it was confirmed that all Rs in the above general formula [1] were H and a compound composed of an oligomer. In addition, non-aqueous electrolyte additive No. GPC measurement of No. 4 was performed, and it was confirmed that the number average molecular weight in terms of polystyrene was 2500. The results are shown in Table 1.

(Preparation of non-aqueous electrolyte additive No. 5)
Add 1.5 g of 2,2′-azobis (isobutyrate) dimethyl (V601: Wako Pure Chemical Industries, Ltd.) to 20 g of NMP in 10 g of VC, perform degassing under vacuum and introducing nitrogen three times, After the atmosphere, the mixture was heated at 80 ° C. for 6 hours. The obtained reaction solution was poured into a large amount of methanol, and the polymer was reprecipitated using the methanol as a poor solvent. The precipitate was separated by filtration, and the polymer was recovered. The obtained polymer was dried at 60 ° C. under reduced pressure for 4 hours to remove the residual solvent, and additive No. for non-aqueous electrolyte solution was obtained. 5 was obtained in a yield of 83%.
Non-aqueous electrolyte additive No. ^{1 was} subjected to ¹ H-NMR measurement, and it was confirmed that all Rs in the above general formula [1] were H and a compound composed of an oligomer. In addition, non-aqueous electrolyte additive No. 5 GPC measurement was performed, and it was confirmed that the number average molecular weight in terms of polystyrene was 4500. The results are shown in Table 1.

(Preparation of non-aqueous electrolyte additive No. 6)
0.5 g of 2,2′-azobis (isobutyric acid) dimethyl (V601: manufactured by Wako Pure Chemical Industries, Ltd.) is added to 20 g of NMP in 10 g of VC, and degassing under vacuum and introduction of nitrogen are performed three times. After the atmosphere, the mixture was heated at 80 ° C. for 6 hours. The obtained reaction solution was poured into a large amount of methanol, and the polymer was reprecipitated using the methanol as a poor solvent. The precipitate was separated by filtration, and the polymer was recovered. The obtained polymer was dried at 60 ° C. under reduced pressure for 4 hours to remove the residual solvent, and additive No. for non-aqueous electrolyte solution was obtained. 6 was obtained in a yield of 81%.
Non-aqueous electrolyte additive No. The ¹ H-NMR measurement of ^No. 6 was performed, and it was confirmed that all the Rs in the general formula [1] were H and that the compound was composed of an oligomer. In addition, non-aqueous electrolyte additive No. GPC measurement of 6 was performed, and it was confirmed that the number average molecular weight in terms of polystyrene was 6500. The results are shown in Table 1.

(Preparation of non-aqueous electrolyte)
The non-aqueous organic solvent (III) was prepared such that ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were in a volume ratio of 3: 7. In this solvent, lithium hexafluorophosphate (LiPF ₆ ) as (IV) was dissolved at a rate of 1 mol / L.
As (I), difluorobis (oxalato) lithium phosphate was added so as to have the concentration shown in Table 2,
By adding the additive for non-aqueous electrolyte solution of the type shown in Table 2 as (II) so that it may become the density | concentration shown in Table 2,
Electrolyte No. 1-1 to 1-14 were obtained.
In addition, electrolyte solution No. In 1-6 and 1-7, VC corresponding to the monomer of (II) is added as the other components so as to be 0.015 mass% and 0.25 mass%, respectively, with respect to the total amount of the electrolytic solution. It was obtained.
In addition, electrolyte No. In 1-3, bis (fluorosulfonyl) imidolithium (hereinafter sometimes referred to as “LiFSI”), 1,3-propane sultone (hereinafter referred to as “PS”) as “second additive” as other components. ), 1,3-propene sultone (hereinafter sometimes referred to as “PRS”), methylenemethane disulfonate (hereinafter sometimes referred to as “MMDS”), 1, 5, 2 , 4-Dioxadithian-6-trifluoroethyl-2,2,4,4-tetraoxide (hereinafter sometimes referred to as “TFP-MDS”), vinyl ethylene carbonate (hereinafter sometimes referred to as “VEC”) ), Bis (difluorophosphoryl) imidolithium (hereinafter sometimes referred to as “LiFPI”), ethoxy (pentafluoro) cyclotriphospha (Hereinafter referred to as HISHICOLLINE E (manufactured by Nippon Chemical Industry Co., Ltd.)), tetrafluorophosphonylpicolinic acid (hereinafter sometimes referred to as “TFPPA”), difluorophosphoryl (fluorophosphoryl) imidodilithium ( Hereinafter referred to as “LiDFP-FPI”), difluorophosphoryl (trifluoromethanesulfonyl) imide lithium (hereinafter sometimes referred to as “LiDFP-TFMSI”), difluorophosphoryl (vinylsulfonyl) imide lithium (hereinafter referred to as “LiDFP”). -VSI "), fluorotrivinylsilane (hereinafter sometimes referred to as" FTVSi "), tetravinylsilane (hereinafter sometimes referred to as" TVSi "), difluorophosphoryl (fluorosulfonyl). Lithium imide (hereinafter may be referred to as "LiDFP-FSI"), respectively, by adding to give a concentration shown in Table 4,
Electrolyte No. 1-15 to 1-29 were obtained.
Moreover, as shown in Table 6, instead of lithium difluorobis (oxalato) phosphate, lithium difluorophosphate (hereinafter referred to as “LiPO ₂ F ₂ ” including the table) is used, and the concentration of (I) , (II) types and concentrations as shown in Table 6, electrolyte No. 2-1 to 2-14 were obtained.
In addition, electrolyte solution No. In 2-6 and 2-7, VC corresponding to the monomer of (II) is added as the other components so that the amount of the liquid becomes 0.015% by mass and 0.25% by mass, respectively, with respect to the total amount of the electrolytic solution. It was obtained.
In addition, electrolyte No. In addition to 2-3, as other components, LiFSI, PS, PRS, MMDS, TFP-MDS, VEC, LiFPI, HISHICOLLINE E, TFPPA, LiDFP-FPI, LiDFP-TFMSI, LiDFP, which are “second additives” By adding −VSI, FTVSi, TVSi, LiDFP-FSI to the concentrations shown in Table 8, respectively,
Electrolyte No. 2-15 to 2-29 were obtained.
Further, instead of difluorobis (oxalato) lithium phosphate, difluorobis (oxalato) lithium phosphate and LiPO ₂ F ₂ are used in the ratio shown in Table 10, and the type and content of (II), ( Except that the type of III) was changed as shown in Table 10, electrolyte No. In the same manner as in 1-14, the electrolyte No. 3-1 to 3-10 were obtained. “EC / EMC / DMC3 / 4/3” is a non-aqueous organic solvent in which EC, EMC, and dimethyl carbonate (DMC) are mixed at a volume ratio of 3: 4: 3, and “EC / EMC / FEC3 / 6”. / 1 ”is a non-aqueous organic solvent in which EC, EMC and fluoroethylene carbonate (FEC) are mixed at a volume ratio of 3: 6: 1, and“ EC / EMC / PC3 / 5/2 ”is EC and EMC. A non-aqueous organic solvent in which propylene carbonate (PC) is mixed at a volume ratio of 3: 5: 2.
In addition, electrolyte No. 3-5, as other components, LiFSI, PS, PRS, MMDS, TFP-MDS, VEC, LiFPI, HISHICOLLINE E, TFPPA, LiDFP-FPI, LiDFP-TFMSI, LiDFP, which are “second additives” By adding −VSI, FTVSi, TVSi, LiDFP-FSI to the concentrations shown in Table 12, respectively,
Electrolyte No. 3-11 to 3-25 were obtained.
Moreover, as shown in Table 14, instead of difluorobis (oxalato) lithium phosphate, difluoro (oxalato) lithium borate was used, and the concentration of (I) and the type and concentration of (II) are shown in Table 14. Electrolyte No. 4-1 to 4-14 were obtained.
In addition, electrolyte solution No. In 4-6 and 4-7, VC corresponding to the monomer of (II) is added as the other components so that the amounts of the components are 0.015% by mass and 0.25% by mass, respectively, with respect to the total amount of the electrolytic solution. It was obtained.
In addition, electrolytic solution No. In addition, as other components, LiFSI, PS, PRS, MMDS, TFP-MDS, VEC, LiFPI, HISHICOLLINE E, TFPPA, LiDFP-FPI, LiDFP-TFMSI, LiDFP- By adding VSI, FTVSi, TVSi, and LiDFP-FSI to the concentrations shown in Table 16, respectively,
Electrolyte No. 4-15 to 4-29 were obtained.
Moreover, as shown in Table 18, instead of using difluorobis (oxalato) lithium phosphate, tetrafluoro (oxalato) lithium phosphate was used, and the concentration of (I) and the type and concentration of (II) are shown in Table 18. Thus, electrolytic solution No. 5-1 to 5-14 were obtained.
In addition, electrolyte solution No. In 5-6 and 5-7, VC corresponding to the monomer of (II) is added as the other components so that the amounts of the components are 0.015% by mass and 0.25% by mass, respectively, with respect to the total amount of the electrolytic solution. It was obtained.
In addition, electrolyte No. In addition, as other components, LiFSI, PS, PRS, MMDS, TFP-MDS, VEC, LiFPI, HISHICOLLINE E, TFPPA, LiDFP-FPI, LiDFP-TFMSI, LiDFP -VSI, FTVSi, TVSi, LiDFP-FSI were added so as to have the concentrations shown in Table 20, respectively.
Electrolyte No. 5-15 to 5-29 were obtained.

Comparative electrolyte No. 1-1 and 1-15-1 to 1-29 were obtained by adding VC corresponding to the monomer of (II) without adding (II) as shown in Table 2 and Table 4.
Comparative electrolyte No. 1-2, as shown in Table 2, (II) as additive No. for non-aqueous electrolyte solution. 6 was added.
Comparative electrolyte No. 2-1, as shown in Table 6, comparative electrolyte No. In 1-1, LiPO ₂ F ₂ is used instead of lithium difluorobis (oxalato) phosphate, and the concentration is 1.0 mass%.
Comparative electrolyte No. As shown in Table 8, each of Nos. 2-15 to 2-29 was electrolytic solution No. except that VC corresponding to the monomer of (II) was added without adding (II). It was obtained in the same manner as 2-15 to 2-29.
Comparative electrolyte No. 2-2, as shown in Table 6, (II) as additive No. for non-aqueous electrolyte solution. 6 was added.
In addition, instead of difluorobis (oxalato) lithium phosphate, difluorobis (oxalato) lithium phosphate and LiPO ₂ F ₂ are used in the ratios shown in Table 10, and the types of (III) are shown in Table 10. Except for the changes as shown, the comparative electrolyte No. In the same manner as in 1-1, the comparative electrolyte No. 3-1 to 3-6 were obtained.
Comparative electrolyte No. 3-11 to 3-25, as shown in Table 12, without adding (II), except that VC corresponding to the monomer of (II) was added, electrolyte No. 3-11, respectively. It was obtained in the same manner as 3-11 to 3-25.
Comparative electrolyte No. 4-1, as shown in Table 14, comparative electrolyte No. In Example 2-1, instead of LiPO ₂ F ₂ , lithium difluoro (oxalato) borate was used.
Comparative electrolyte No. 4-2, as shown in Table 14, (II) as additive No. for non-aqueous electrolyte solution. 6 was added.
Comparative electrolyte No. 4-15 to 4-29, as shown in Table 16, without adding (II), except that VC corresponding to the monomer of (II) was added. It was obtained in the same manner as 4-15 to 4-29.
Comparative electrolyte No. As shown in Table 18, the comparative electrolyte No. In Example 2-1, instead of LiPO ₂ F ₂ , lithium tetrafluoro (oxalato) phosphate was used.
Comparative electrolyte No. 5-2, as shown in Table 18, (II) as non-aqueous electrolyte additive No. 6 was added.
Comparative electrolyte No. 5-15 to 5-29, as shown in Table 20, without adding (II), except that VC corresponding to the monomer of (II) was added. It was obtained in the same manner as 5-15 to 5-29.

Using this electrolyte, a cell was fabricated using LiNi _1/3 Co _1/3 Mn _1/3 O ₂ as the positive electrode material and graphite as the negative electrode material, and the initial electric capacity, cycle characteristics, and rate characteristics of the battery were actually evaluated. did. The test cell was produced as follows.

Mixing 90% by mass of LiNi _1/3 Co _1/3 Mn _1/3 O ₂ powder with 5% by mass of polyvinylidene fluoride (hereinafter referred to as “PVDF”) as a binder and 5% by mass of acetylene black as a conductive material, Further, N-methylpyrrolidone was added to make a paste. The paste was applied on an aluminum foil and dried to obtain a test positive electrode body. Further, 90% by mass of graphite powder was mixed with 10% by mass of PVDF as a binder, and N-methylpyrrolidone was further added to form a slurry. This slurry was applied on a copper foil and dried at 150 ° C. for 12 hours to obtain a test negative electrode body. Then, an electrolytic solution was immersed in a polyethylene separator to assemble a 50 mAh cell with an aluminum laminate exterior.

[Initial capacitance]
Using the fabricated cell, after charging to 4.2 V at a current density of 0.35 mA / cm ² , the battery was discharged to 3.0 V at a current density of 0.35 mA / cm ^2. The capacity. The measurement was performed at an ambient temperature of 25 ° C.

[High temperature cycle characteristics]
Using the above cell, a charge / discharge test was conducted at an environmental temperature of 60 ° C. to evaluate the cycle characteristics. Both charging and discharging were performed at a current rate of 3 C. After reaching 4.2 V, charging was maintained at 4.2 V for 1 hour, discharging was performed up to 3.0 V, and the charge / discharge cycle was repeated. Then, the degree of deterioration of the cell was evaluated based on the discharge capacity maintenance rate after 500 cycles (cycle characteristic evaluation). The discharge capacity retention rate was determined by the following formula.
<Discharge capacity maintenance rate after 500 cycles>
Discharge capacity retention rate (%) = (discharge capacity after 500 cycles / initial discharge capacity) × 100
The results are shown in Tables 3, 5, 7, 9, 11, 13, 15, 17, 19, 21.
Note that the values of the cycle characteristics in Tables 3, 7, 15, and 19 are relative values with the value of the cycle characteristics of Comparative Examples 1-1, 2-1, 4-1, and 5-1 being 100, respectively.
In the cycle characteristics shown in Table 11, the values of Examples 3-1 and 3-7 to 3-10 are relative values with the value of Comparative Example 3-1 being 100, and the values of Example 3-2 are comparative. The value of Example 3-2 is a relative value with 100, the value of Example 3-3 is a relative value with the value of Comparative Example 3-3 as 100, and the value of Example 3-4 is Comparative Example 3. -4 is a relative value with a value of 100, the value of Example 3-5 is a relative value with a value of Comparative Example 3-5 as 100, and the value of Example 3-6 is Comparative Example 3-6 The relative value with the value of 100 as 100.
In addition, the values of the cycle characteristics in Tables 5, 9, 13, 17, and 21 are relative values with the value of the cycle characteristics of the corresponding comparative example being 100.

[Rate characteristics]
Using the above cell, a charge / discharge test was conducted at an environmental temperature of 25 ° C. to evaluate high rate characteristics. Charging is always performed at a current rate of 0.2C, and after 4.2V is reached, 4.2V is maintained for 1 hour. Discharging is performed up to 3.0V with two data points at a current rate of 0.2C and 5C. The discharge capacity ratio at the time of 0.2C discharge and 5C discharge was determined by the following formula.
<High capacity discharge capacity ratio>
High rate discharge capacity ratio (%) = (discharge capacity at 5 C discharge / discharge capacity at 0.2 C discharge) × 100
The results are shown in Tables 3, 5, 7, 9, 11, 13, 15, 17, 19, 21.
The values of rate characteristics in Tables 3, 7, 15, and 19 are relative values with the rate characteristic values of Comparative Examples 1-1, 2-1, 4-1, and 5-1 being 100, respectively.
In the rate characteristics of Table 11, the values of Examples 3-1 and 3-7 to 3-10 are relative values with the value of Comparative Example 3-1 being 100, and the values of Example 3-2 are comparative. The value of Example 3-2 is a relative value with 100, the value of Example 3-3 is a relative value with the value of Comparative Example 3-3 as 100, and the value of Example 3-4 is Comparative Example 3. -4 is a relative value with a value of 100, the value of Example 3-5 is a relative value with a value of Comparative Example 3-5 as 100, and the value of Example 3-6 is Comparative Example 3-6 The relative value with the value of 100 as 100.
In addition, the rate characteristic values in Tables 5, 9, 13, 17, and 21 are relative values with the rate characteristic value of the corresponding comparative example being 100.

As can be seen from Examples 1-1 to 1-5,
When the polystyrene-equivalent number average molecular weight of the additive for non-aqueous electrolyte solution of the present invention is 170 to 5,000, when used in a non-aqueous electrolyte secondary battery, cycle characteristics and rate characteristics can be exhibited in a well-balanced manner. it can.
On the other hand, a comparison using an electrolytic solution in which VC corresponding to the monomer (compound corresponding to the monomer of the general formula [1]) was added instead of the non-aqueous electrolytic solution additive of the present invention was added. In Example 1-1, it was confirmed that the cycle characteristics and rate characteristics tend to be inferior to those of the above examples.
In addition, in Comparative Example 1-2 in which a compound having a polystyrene-equivalent number average molecular weight of more than 5000 was added, it was confirmed that the cycle characteristics and rate characteristics tend to be inferior to those of the above Examples.

  Moreover, from Example 1-3 and 1-8 to 1-13, content of (II) with respect to 100 mass% of total amounts of said (I), (II), (III), (IV) is 0.03-. When it is 14.0% by mass, when used in a non-aqueous electrolyte secondary battery, the cycle characteristics and rate characteristics are easily exhibited in a balanced manner, and the content of (II) is 0.07 to 12.0% by mass. It turns out that it is more preferable that it is.

  Moreover, it is confirmed from Examples 1-6 and 1-7 that the rate characteristics tend to be better when the value of (M) / (P) (mass ratio) is 0 to 0.05. It was.

  Further, as can be seen from Examples 2-1 to 2-14, even when a difluorophosphate is used as (I), the cycle characteristics and rate characteristics can be improved by using the non-aqueous electrolyte additive of the present invention. Can be balanced.

  In addition, as can be seen from Examples 3-1 to 3-10, when the oxalato salt and the difluorophosphate are used as (I), the cycle characteristics and the non-aqueous electrolyte solution additive of the present invention are used. The rate characteristics can be exhibited in a well-balanced manner.

  In addition, as can be seen from Examples 4-1 to 4-14, when lithium difluoro (oxalato) borate is used as (I), the cycle characteristics and the nonaqueous electrolyte solution additive of the present invention are used. The rate characteristics can be exhibited in a well-balanced manner.

  Further, as can be seen from Examples 5-1 to 5-14, also when lithium tetrafluoro (oxalato) phosphate is used as (I), the cycle characteristics can be obtained by using the additive for non-aqueous electrolyte of the present invention. In addition, the rate characteristics can be exhibited in a well-balanced manner.

  Examples 1-15 to 1-29, Examples 2-15 to 2-29, Examples 3-11 to 3-25, Examples 4-15 to 4-29, Examples 5-15 to 5-5 As can be seen from FIG. 29, when the electrolyte containing the “second additive” is used as the other component, the non-aqueous electrolyte additive of the present invention is used to provide a good balance between cycle characteristics and rate characteristics. It can be demonstrated.

Claims (16)

A compound having a repeating unit represented by the following general formula [1]:
The number average molecular weight in terms of polystyrene is 170 to 5000,
An additive for a non-aqueous electrolyte solution for inclusion in a non-aqueous electrolyte solution containing an oxalato salt and / or a difluorophosphate.

[Wherein the parentheses mean that each is a repeating unit. R represents a hydrogen atom, a halogen or a lower alkyl group. R may be all the same or different, and may be linked to each other to have a cyclic structure. ] The additive for non-aqueous electrolyte solutions according to claim 1, wherein the number average molecular weight is 340 to 4000. The additive for non-aqueous electrolyte solutions according to claim 1 or 2, wherein the number average molecular weight is 800 to 3000. The additive for non-aqueous electrolyte solutions according to any one of claims 1 to 3, wherein all the Rs are hydrogen atoms. (I) Oxalato salt and / or difluorophosphate,
(II) A compound having a repeating unit represented by the following general formula [1], and having a polystyrene-equivalent number average molecular weight of 170 to 5,000, an additive for non-aqueous electrolyte solution,
(III) a non-aqueous organic solvent, and
(IV) A nonaqueous electrolytic solution containing a solute.

[Wherein the parentheses mean that each is a repeating unit. R represents a hydrogen atom, a halogen or a lower alkyl group. R may be all the same or different, and may be linked to each other to have a cyclic structure. ] The non-aqueous electrolyte solution according to claim 5, wherein the number average molecular weight is 340 to 4000. The non-aqueous electrolyte solution according to claim 5 or 6, wherein the number average molecular weight is 800 to 3000. The non-aqueous electrolyte solution according to claim 5, wherein all R are hydrogen atoms. The content of (II) is 0.03 to 14.0% by mass with respect to 100% by mass of the total amount of (I), (II), (III), and (IV). The non-aqueous electrolyte described. Present in the electrolyte,
A total amount of monomers corresponding to the repeating unit represented by the general formula [1] (hereinafter referred to as (M));
The total amount of the non-aqueous electrolyte additive (in terms of monomer, hereinafter referred to as (P))
(M) / (P) = 0-0.05 (mass ratio)
The non-aqueous electrolyte solution according to any one of claims 5 to 9, wherein The oxalato salt includes bis (oxalato) borate, difluoro (oxalato) borate, tris (oxalato) phosphate, difluorobis (oxalato) phosphate, and tetrafluoro (oxalato) phosphate. The non-aqueous electrolyte solution according to claim 5, which is at least one selected from the group. The solute is lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis (trifluoromethanesulfonyl) imide lithium, bis (pentafluoroethanesulfonyl) imide lithium, bis (fluorosulfonyl) imide lithium, and bis (difluorophosphonyl). The non-aqueous electrolyte solution according to claim 5, which is at least one selected from the group consisting of imidolithium. The nonaqueous electrolytic solution according to any one of claims 5 to 12, comprising (I) at least lithium difluorobis (oxalato) phosphate and lithium difluorophosphate. The non-aqueous solvent is at least one selected from the group consisting of a cyclic carbonate, a chain carbonate, a cyclic ester, a chain ester, a cyclic ether, a chain ether, a sulfone compound, a sulfoxide compound, and an ionic liquid. The non-aqueous electrolyte solution in any one of 5-13. Ionic complex having cyclic structure, salt having imide anion, Si-containing compound, sulfate ester compound, phosphate ester compound, cyclic carbonate compound, isocyanate compound, cyclic acetal compound, cyclic acid anhydride, cyclic phosphazene compound, aromatic compound At least one compound selected from the group consisting of:
Furthermore, the non-aqueous electrolyte solution in any one of Claims 5-14 contained. A non-aqueous electrolyte secondary battery comprising at least a positive electrode, a negative electrode, and the non-aqueous electrolyte solution according to claim 5.