Secondary battery non-aqueous electrolyte and secondary battery provided with same

Abstract

The present invention discloses a secondary battery non-aqueous electrolyte for use in a secondary battery, said electrolyte being characterized by containing at least one type of component (A) and at least one type of component (B) as an additive.　Component (A): Compounds represented by chemical formula (1) Component (B): At least one compound selected from the group consisting of boric acid esters or boron complex salts represented by chemical formula (2), acid anhydrides, cyclic carbonates with unsaturated bonds, cyclic carbonates with halogen atoms, cyclic sulfonates, cyclic sulfonic acid esters, cyclic sulfuric acid esters, cyclic sulfite esters, amines with an acetoacetyl group represented by chemical formula (3), phosphorus compounds represented by any of chemical formulas (4) to (6), sulfonyl imide salts and sulfonates, and dinitriles The non-aqueous electrolyte according to the present embodiment can be used suitably in lithium-ion secondary batteries, for example.

Description

Nonaqueous electrolyte for secondary battery and secondary battery including same

[0001] The present invention relates to a nonaqueous electrolyte for secondary batteries, which is excellent in terms of the retention of electrical capacity and the suppression of an increase in internal resistance when stored in a high-temperature environment, for example, for secondary batteries used at high voltages, and which also has excellent retention of electrical capacity when repeatedly charged and discharged, and to a secondary battery including the same.

[0002] Lithium secondary batteries, which are small, high-capacity energy storage devices, have become widely used as power sources for portable information terminals such as laptops, digital cameras, mobile phones, smartphones, tablets, etc. In recent years, as key devices for achieving carbon neutrality, their applications have expanded to include electric vehicles (xEVs) and stationary storage batteries for home and mega-solar power generation systems, and lithium secondary batteries with higher energy density are being developed.

[0003] In conventional lithium secondary batteries, materials capable of reversibly inserting Li ions are used as the positive electrode active material and the negative electrode active material. For example, LiNiO ２ , LiCoO ２ , LiMn ２ O ４ , or LiFePO ４ The negative electrode active material is lithium metal, its alloy, a carbon material, a graphite material, or the like. The electrolyte used in lithium secondary batteries is a mixed solvent of ethylene carbonate, diethyl carbonate, propylene carbonate, or the like, containing LiPF ６ , LiBF ４ In this case, a material in which an electrolyte such as the above is dissolved is used.

[0004] It is generally understood that a stable film (SEI: Solid Electrolyte Interface) that has lithium ion conductivity but no electronic conductivity is formed at the interface between the electrode active material and the electrolyte. The process of lithium ion insertion and desorption into the electrode active material is highly reversible, but repeated charge and discharge in a high-temperature environment tends to cause cracks, dissolution, or decomposition at the stable interface, resulting in a decrease in charge and discharge characteristics and an increase in impedance.

[0005] Patent Document 1 discloses that by adding a lithium compound such as lithium phenoxide to a non-aqueous electrolyte for a lithium secondary battery, good results can be obtained, particularly in terms of cycle characteristics.

[0006] Patent Document 2 discloses that by using a non-aqueous electrolyte solution containing lithium phenoxide, which is a weakly acidic organic lithium salt, hydrogen gas generated during overcharging of a lithium secondary battery can be trapped, thereby providing a lithium secondary battery with excellent safety.

[0007] JP 1998-270077 A JP 2003-187863 A

[0008] However, it has been found that there is room for improvement in the characteristics of Patent Documents 1 and 2, particularly in high-temperature environments.

[0009] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a nonaqueous electrolyte for a secondary battery that exhibits excellent storage performance and reduced internal resistance even in a high-temperature environment and exhibits excellent cycle characteristics even at a high charging voltage, and a secondary battery including the same.

[0010] In order to solve the above-mentioned problems, the nonaqueous electrolyte solution for a secondary battery of the present invention is a nonaqueous electrolyte solution for a secondary battery used in a secondary battery, and is characterized by containing at least one of the following components (A) and at least one of the following components (B) as additives:

[0011] Component (A): A compound represented by the following chemical formula (1): (However, the above M ｎ＋ represents any one ion selected from the group consisting of alkali metal ions, alkaline earth metal ions, aluminum ions, transition metal ions, and onium ions. １ ~α ５each independently represents a hydrogen atom, a halogen atom, a hydroxy group, a mercapto group, a nitro group, a formyl group, a sulfo group, a carboxy group, an acetyl group, a sulfonamido group, a cyano group, an amino group, a thio group containing a hydrocarbon group having 1 to 20 carbon atoms, an amino group containing a hydrocarbon group having 1 to 20 carbon atoms, a sulfonyl group containing a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon group or alkoxy group having 1 to 20 carbon atoms, or a hydrocarbon group or alkoxy group having 1 to 20 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond. １ ~α ５ represents a hydrocarbon group or alkoxy group having 1 to 20 carbon atoms, or a hydrocarbon group or alkoxy group having 1 to 20 carbon atoms and at least one of a halogen atom, a hetero atom, or an unsaturated bond, which are mutually bonded to form a cyclic structure. The n represents the valence.

[0012] Component (B): A boron complex salt represented by the following chemical formula (2), or at least one compound selected from the group consisting of boric acid esters, acid anhydrides, cyclic carbonates having an unsaturated bond, cyclic carbonates having a halogen atom, cyclic sulfonate esters, cyclic sulfate esters, cyclic sulfite esters, amines having an acetoacetyl group represented by the following chemical formula (3), phosphorus compounds represented by any of the following chemical formulas (4) to (6), sulfonylimide salts and sulfonate salts, and dinitriles.

[0013] (The M ｎ＋ represents a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an aluminum ion, a transition metal ion, or an onium ion. １ ~X ４ are each independent, and an arbitrarily selected combination of one or two of them forms a cyclic structure of -OOC-COO-, -OOCO-, -OOC-Y-COO-, -O-Y-O- or -OOC-Y-O-, in which case each Y independently represents a hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and having a heteroatom, an unsaturated bond or a cyclic structure.１ ~X ４ each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond, or an alkoxy group having 1 to 20 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond, and n represents a valence.

[0014] (The above R ２ and R ３ each independently represents a hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and containing a halogen atom, a heteroatom, or an unsaturated bond.

[0015] (In the formula, the M ｎ＋ represents a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an aluminum ion, a transition metal ion, or an onium ion. １ and A ２ Each of the X independently represents an oxygen atom, a sulfur atom, or a selenium atom. ５ and X ６ each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond. ５ and X ６ is either an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond, which are bonded to each other to form a cyclic structure, and n represents the valence.

[0016] (In the formula, the M ｎ＋ represents a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an aluminum ion, a transition metal ion, or an onium ion. ７ ~X １２each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylthio group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms and having at least one of a halogen atom, a heteroatom, or an unsaturated bond, an alkylthio group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms and having at least one of a halogen atom, a heteroatom, or an unsaturated bond, an alkylthio group having 1 to 20 carbon atoms, or an alkylthio group having 1 to 20 carbon atoms and having at least one of a halogen atom, a heteroatom, or an unsaturated bond. ７ ~X １２ at least one arbitrarily selected combination forms a cyclic structure of -OOC-COO-, -OOCO-, -OOC-Z-COO-, -OOC-Z-O- or -O-Z-O-, in which case Z represents a hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and at least one of a halogen atom, a heteroatom, an unsaturated bond, or a cyclic structure; and n represents a valence.

[0017] (The M ｎ＋ represents a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an aluminum ion, a transition metal ion, or an onium ion. ４ and R ５ each independently represents a hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and at least one of a halogen atom, a hetero atom, and an unsaturated bond. ４ and R ５ represents either a hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and at least one of a halogen atom, a hetero atom, or an unsaturated bond, which are bonded to each other to form a cyclic structure. The n represents the valence.

[0018] In the above-mentioned configuration, the content of the component (A) is preferably 0.05 to 5% by mass based on the total mass of the nonaqueous electrolyte solution for a secondary battery.

[0019] In the above-mentioned configuration, the content of the component (B) is preferably 0.05 to 5% by mass based on the total mass of the nonaqueous electrolyte solution for secondary batteries.

[0020] In the above-mentioned configuration, the component (A) is preferably lithium phenoxide, lithium 4-tert-amylphenoxide, or sodium phenoxide.

[0021] In the above-mentioned configuration, the component (B) is preferably 1,3-propane sultone.

[0022] In the above-mentioned configuration, the component (B) is preferably vinylene carbonate.

[0023] In the above-mentioned configuration, the component (B) is preferably fluoroethylene carbonate.

[0024] In the above-mentioned configuration, the component (B) is preferably lithium difluorophosphate.

[0025] In the above-mentioned configuration, the component (B) is preferably lithium difluorooxalatoborate.

[0026] In the above-mentioned configuration, the component (B) is preferably lithium difluorobisoxalatophosphate.

[0027] In the above-mentioned configuration, the component (B) is preferably lithium tetrafluorooxalatophosphate.

[0028] In the above-mentioned structure, the component (B) is preferably lithium bis(fluorosulfonyl)imide.

[0029] In the above-mentioned configuration, the component (B) is preferably lithium fluorosulfonate.

[0030] In the above-mentioned configuration, the component (B) is preferably succinonitrile.

[0031] In order to solve the above-mentioned problems, the secondary battery of the present invention is characterized by comprising at least the nonaqueous electrolyte for secondary batteries, a positive electrode, and a negative electrode described above.

[0032] According to the present invention, it is possible to provide a nonaqueous electrolyte for a secondary battery, which exhibits excellent storage performance and reduced internal resistance even in a high-temperature environment and exhibits excellent cycle characteristics even at a high charging voltage, and a secondary battery including the same. Although the mechanism is not clear, it is presumed that the inclusion of at least one type of component (A) and at least one type of component (B) as additives forms a film on the surface of the electrode active material, and that the properties of the film, i.e., thermal stability, film quality, etc., improve the cycle characteristics in a high-temperature environment.

[0033] 1 is a cross-sectional view showing an outline of a lithium ion secondary battery including a nonaqueous electrolyte solution for a secondary battery according to an embodiment of the present invention.

[0034] (Non-aqueous electrolyte for secondary battery) The non-aqueous electrolyte for secondary battery according to the present embodiment (hereinafter referred to as "nonaqueous electrolyte") contains at least one type of component (A) described below and at least one type of component (B) described below as additives to an organic solvent (nonaqueous solvent) in which an electrolyte is dissolved.

[0035] During initial charging, an irreversible reaction, namely decomposition of the non-aqueous electrolyte, occurs at the interface between the electrode and the non-aqueous electrolyte. It is believed that the properties of the film formed, such as thermal stability, ionic conductivity, morphology, and density, vary significantly depending on the electrode active material, the type of non-aqueous solvent, electrolyte, and additives in the non-aqueous electrolyte, and the charge / discharge conditions. In this embodiment, too, by adding components (A) and (B) together to the non-aqueous electrolyte, a film is formed on the surface of the electrode active material, and the properties of this film, i.e., thermal stability and film quality, are believed to improve the cycle characteristics of the secondary battery in high-temperature environments (e.g., 40°C to 80°C).

[0036] <Component (A)> The component (A) is contained in the non-aqueous electrolyte solution in one kind, and specifically, is a compound represented by the following chemical formula (1).

[0037]

[0038] In the chemical formula (1), the M ｎ＋ represents any one selected from the group consisting of alkali metal ions, alkaline earth metal ions, aluminum ions, transition metal ions and onium ions.

[0039] The alkali metal ions are not particularly limited and include lithium ions, sodium ions, potassium ions, rubidium ions, cesium ions, etc. These can be used alone or in combination of two or more.

[0040] Examples of the alkaline earth metal ions include magnesium ions, calcium ions, strontium ions, barium ions, etc. These can be used alone or in combination of two or more.

[0041] The transition metal ions are not particularly limited and include, for example, manganese ions, cobalt ions, nickel ions, chromium ions, copper ions, silver ions, molybdenum ions, tungsten ions, vanadium ions, etc. These may be used alone or in combination of two or more.

[0042] The onium ion may be an ammonium ion (NH ４＋ ), primary ammonium ions, secondary ammonium ions, tertiary ammonium ions, quaternary ammonium ions, quaternary phosphonium ions, sulfonium ions, and the like.

[0043] The primary ammonium ion is not particularly limited, and examples thereof include methylammonium ion, ethylammonium ion, propylammonium ion, isopropylammonium ion, etc. These may be used alone or in combination of two or more.

[0044] The secondary ammonium ion is not particularly limited, and examples thereof include dimethylammonium ion, diethylammonium ion, dipropylammonium ion, dibutylammonium ion, ethylmethylammonium ion, methylpropylammonium ion, methylbutylammonium ion, propylbutylammonium ion, diisopropylammonium ion, etc. These can be used alone or in combination of two or more.

[0045] The tertiary ammonium ion is not particularly limited, and examples thereof include trimethylammonium ion, triethylammonium ion, tripropylammonium ion, tributylammonium ion, ethyldimethylammonium ion, diethylmethylammonium ion, triisopropylammonium ion, dimethylisopropylammonium ion, diethylisopropylammonium ion, dimethylpropylammonium ion, butyldimethylammonium ion, 1-methylpyrrolidinium ion, 1-ethylpyrrolidinium ion, 1-propylpyrrolidinium ion, 1-butylpropylpyrrolidinium ion, 1-methylimidazolium ion, 1-ethylimidazolium ion, 1-propylimidazolium ion, 1-butylimidazolium ion, pyrazolium ion, 1-methylpyrazolium ion, 1-ethylpyrazolium ion, 1-propylpyrazolium ion, 1-butylpyrazolium ion, pyridinium ion, etc. These ion may be used alone or in combination of two or more.

[0046] The quaternary ammonium constituting the quaternary ammonium ion is not particularly limited, and examples thereof include aliphatic quaternary ammoniums, imidazoliums, pyridiniums, pyrazoliums, pyridaziniums, etc. These may be used alone or in combination of two or more.

[0047] Furthermore, the aliphatic quaternary ammoniums are not particularly limited, and examples thereof include tetraethylammonium, tetrapropylammonium, tetraisopropylammonium, trimethylethylammonium, dimethyldiethylammonium, methyltriethylammonium, trimethylpropylammonium, trimethylisopropylammonium, tetrabutylammonium, trimethylbutylammonium, trimethylpentylammonium, trimethylhexylammonium, 1-ethyl-1-methyl-pyrrolidinium, 1-butyl-1-methylpyrrolidinium, 1-ethyl-1-methyl-piperidinium, 1-butyl-1-methylpiperidinium, etc. These can be used alone or in combination of two or more.

[0048] The imidazoliums are not particularly limited, and examples thereof include 1,3-dimethyl-imidazolium, 1-ethyl-3-methylimidazolium, 1-n-propyl-3-methylimidazolium, 1-n-butyl-3-methylimidazolium, 1-n-hexyl-3-methylimidazolium, etc. These can be used alone or in combination of two or more.

[0049] The pyridinium compounds are not particularly limited and include, for example, 1-methylpyridinium, 1-ethylpyridinium, 1-n-propylpyridinium, etc. These can be used alone or in combination of two or more.

[0050] The pyrazoliums are not particularly limited, and examples thereof include 1,2-dimethylpyrazolium, 1-methyl-2-ethylpyrazolium, 1-propyl-2-methylpyrazolium, 1-methyl-2-butylpyrazolium, 1-methylpyrazolium, 3-methylpyrazolium, 4-methylpyrazolium, 4-iodopyrazolium, 4-bromopyrazolium, 4-iodo-3-methylpyrazolium, 4-bromo-3-methylpyrazolium, and 3-trifluoromethylpyrazolium. These may be used alone or in combination of two or more.

[0051] The pyridaziniums are not particularly limited, and examples thereof include 1-methylpyridazinium, 1-ethylpyridazinium, 1-propylpyridazinium, 1-butylpyridazinium, 3-methylpyridazinium, 4-methylpyridazinium, 3-methoxypyridazinium, 3,6-dichloropyridazinium, 3,6-dichloro-4-methylpyridazinium, 3-chloro-6-methylpyridazinium, and 3-chloro-6-methoxypyridazinium. These can be used alone or in combination of two or more.

[0052] The quaternary phosphonium constituting the quaternary phosphonium ion is not particularly limited, and examples thereof include benzyltriphenylphosphonium, tetraethylphosphonium, tetraphenylphosphonium, etc. These can be used alone or in combination of two or more.

[0053] The sulfonium ion is not particularly limited, and examples thereof include trimethylsulfonium, triphenylsulfonium, triethylsulfonium, etc. These can be used alone or in combination of two or more.

[0054] Said M ｎ＋ Among those listed as examples, from the viewpoint of availability, lithium ions, sodium ions, potassium ions, magnesium ions, calcium ions, tetraalkylammonium ions, alkylimidazolium ions, alkylpyrrolidinium ions, and alkylpyridinium ions are preferred.

[0055] In the chemical formula (1), the α １ ~α ５each independently represents a hydrogen atom, a halogen atom, a hydroxy group, a mercapto group, a nitro group, a formyl group, a sulfo group, a carboxy group, an acetyl group, a sulfonamido group, a cyano group, an amino group, a thio group containing a hydrocarbon group, an amino group containing a hydrocarbon group, a sulfonyl group containing a hydrocarbon group, a hydrocarbon group, an alkoxy group, or a hydrocarbon group or alkoxy group having at least one of a halogen atom, a heteroatom, or an unsaturated bond (hereinafter referred to as a "hydrocarbon group or alkoxy group having a halogen atom or the like"). The number of carbon atoms in the hydrocarbon-containing thio group, hydrocarbon-containing amino group, hydrocarbon-containing sulfonyl group, hydrocarbon group, alkoxy group, and hydrocarbon group or alkoxy group having a halogen atom or the like is in the range of 1 to 20, preferably 1 to 10, and more preferably 1 to 4. The number of unsaturated bonds is preferably in the range of 1 to 10, more preferably 1 to 5, and particularly preferably 1 to 3.

[0056] The halogen atom is any one of iodine, bromine, chlorine, and fluorine.

[0057] The thio group containing a hydrocarbon group is not particularly limited, and examples thereof include a methylthio group, an ethylthio group, a phenylthio group, and a benzylthio group.

[0058] The amino group containing a hydrocarbon group is not particularly limited, and examples thereof include a methylamino group, a dimethylamino group, an ethylamino group, a diethylamino group, and a phenylamino group.

[0059] The sulfonyl group containing a hydrocarbon group is not particularly limited, and examples thereof include a methanesulfonyl group, an ethanesulfonyl group, a benzenesulfonyl group, and a p-toluenesulfonyl group.

[0060] The hydrocarbon group or hydrocarbon group having a halogen atom or the like is not particularly limited, and examples thereof include chain alkyl groups such as methyl group, ethyl group, propyl group, butyl group, isopropyl group, pentyl group, tert-amyl group, hexyl group, heptyl group, and octyl group; cyclic alkyl groups such as cyclopentyl group and cyclohexyl group; 2-iodoethyl group, 2-bromoethyl group, 2-chloroethyl group, 2-fluoroethyl group, 1,2-diiodoethyl group, 1,2-dibromoethyl group, 1,2-dichloroethyl group, 1,2-difluoroethyl group, and the like. Chain halogen-containing alkyl groups such as ethyl group, 2,2-diiodoethyl group, 2,2-dibromoethyl group, 2,2-dichloroethyl group, 2,2-difluoroethyl group, 2,2,2-tribromoethyl group, 2,2,2-trichloroethyl group, 2,2,2-trifluoroethyl group, and hexafluoro-2-propyl group; cyclic halogen-containing alkyl groups such as 2-iodocyclohexyl group, 2-bromocyclohexyl group, 2-chlorocyclohexyl group, and 2-fluorocyclohexyl group; 2-propenyl group, isopropenyl group, 2-butene group, chain alkenyl groups such as a 2-cyclopentenyl group, a 2-cyclohexenyl group, and a 3-cyclohexenyl group; chain alkynyl groups such as a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, a 3-butynyl group, a 1-pentynyl group, a 2-pentynyl group, a 3-pentynyl group, and a 4-pentynyl group; phenyl groups such as a phenyl group, a 3-methoxyphenyl group, a 4-methoxyphenyl group, a 3,5-dimethoxyphenyl group, and a 4-phenoxyphenyl group; 2-iodophenyl group, 2-bromophenyl group, and a 2-bromophenyl group; halogen-containing phenyl groups such as a 1-naphthyl group, a 2-naphthyl group, a 3-amino-2-naphthyl group, a 3-amino-2-naphthyl group, a 1 ...

[0061] The alkoxy group or alkoxy group having a halogen atom or the like is not particularly limited, and examples thereof include chain alkoxy groups such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentoxy group, and a hexoxy group; cyclic alkoxy groups such as a cyclopentoxy group and a cyclohexoxy group; 2-iodoethoxy group, a 2-bromoethoxy group, a 2-chloroethoxy group, a 2-fluoroethoxy group, a 1,2-diiodoethoxy group, a 1,2-dibromoethoxy group, a 1,2-dichloroethoxy group, a 1,2-difluoroethoxy group, a 2,2-diiodoethoxy group, a 2 ... chain-containing halogen-containing alkoxy groups such as 2,2-dibromoethoxy group, 2,2-dichloroethoxy group, 2,2-difluoroethoxy group, 2,2,2-tribromoethoxy group, 2,2,2-trichloroethoxy group, 2,2,2-trifluoroethoxy group, and 1,1,1,3,3,3-hexafluoro-2-propoxy group; cyclic halogen-containing alkoxy groups such as 2-iodocyclohexoxy group, 2-bromocyclohexoxy group, 2-chlorocyclohexoxy group, and 2-fluorocyclohexoxy group; 2-propenoxy group, isopropanol group, and the like; Chain alkenylalkoxy groups such as pentoxy, 2-butenoxy, and 3-butenoxy groups; cyclic alkenylalkoxy groups such as 2-cyclopentenoxy, 2-cyclohexenoxy, and 3-cyclohexenoxy groups; chain alkynylalkoxy groups such as 2-propynoxy, 1-butynoxy, 2-butynoxy, 3-butynoxy, 1-pentynoxy, 2-pentynoxy, 3-pentynoxy, and 4-pentynoxy groups; phenoxy, 3-methylphenoxy, 4-methylphenoxy, and 3,5-dimethylphenoxy groups; and halogen-containing phenoxy groups such as a phenoxy group, a 2-iodophenoxy group, a 2-bromophenoxy group, a 2-chlorophenoxy group, a 2-fluorophenoxy group, a 3-iodophenoxy group, a 3-bromophenoxy group, a 3-chlorophenoxy group, a 3-fluorophenoxy group, a 4-iodophenoxy group, a 4-bromophenoxy group, a 4-chlorophenoxy group, a 4-fluorophenoxy group, a 3,5-diiodophenoxy group, a 3,5-dibrophenoxy group, a 3,5-dichlorophenoxy group, and a 3,5-difluorophenoxy group.

[0062] In addition, the α １ ~α ５may be a group in which the hydrocarbon group or alkoxy group, or the hydrocarbon group or alkoxy group having at least one of a halogen atom, a hetero atom, or an unsaturated bond, is bonded to each other to form a cyclic structure. １ ~α ５ Examples of the hydrocarbon group or hydrocarbon group having a halogen atom or the like in the formula (I) include linear alkylene groups such as methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, and nonylene groups, iodomethylene, diiodomethylene, bromomethylene, dibromomethylene, fluoromethylene, difluoromethylene, iodoethylene, 1,1-diiodoethylene, 1,2-diiodoethylene, triiodoethylene, and tetraiodoethylene. Examples of the alkylene groups include halogen-containing linear alkylene groups such as ethylene group, chloroethylene group, 1,1-dichloroethylene group, 1,2-dichloroethylene group, trichloroethylene group, tetrachloroethylene group, fluoroethylene group, 1,1-difluoroethylene group, 1,2-difluoroethylene group, trifluoroethylene group, and tetrafluoroethylene group, and cyclic hydrocarbon groups such as cyclohexylene group, phenylene group, benzylene group, naphthylene group, anthracylene group, naphthasylene group, and pentasylene group. １ ~α ５Examples of the alkoxy group or alkoxy group having a halogen atom or the like in the above formula include linear alkylene dioxy groups such as methylenedioxy group, ethylenedioxy group, propylenedioxy group, butylenedioxy group, pentylenedioxy group, hexylenedioxy group, heptylenedioxy group, octylenedioxy group, and nonylenedioxy group; cyclic alkylene dioxy groups such as cyclohexylenedioxy group; iodomethylenedioxy group, diiodomethylenedioxy group, bromomethylenedioxy group, dibromomethylenedioxy group, fluoromethylenedioxy group, difluoromethylenedioxy group, iodoethylenedioxy group, 1,1-diiodoethylenedioxy group, 1,2-diiodoethylenedioxy group, and triiodoethylenedioxy group. halogen-containing linear alkylenedioxy groups such as a tetraiodoethylenedioxy group, a chloroethylenedioxy group, a 1,1-dichloroethylenedioxy group, a 1,2-dichloroethylenedioxy group, a trichloroethylenedioxy group, a tetrachloroethylenedioxy group, a fluoroethylenedioxy group, a 1,1-difluoroethylenedioxy group, a 1,2-difluoroethylenedioxy group, a trifluoroethylenedioxy group, and a tetrafluoroethylenedioxy group; arylenedioxy groups such as a phenylenedioxy group, a benzylenedioxy group, a naphthylenedioxy group, an anthracylenedioxy group, a naphthacylenedioxy group, and a pentasylenedioxy group; and groups in which a part or all of these groups have been replaced with a halogen atom or the like.

[0063] The α １ ~α ５ may be the same or different from each other. １ ~α ５ The functional groups listed above as are merely examples, and the present embodiment is not limited to these.

[0064] The halogen atom refers to a fluorine, chlorine, bromine, or iodine atom. The hydrocarbon group having a halogen atom means that some or all of the hydrogen atoms in the hydrocarbon group may be substituted with any of these halogen atoms. The heteroatom refers to an atom such as oxygen, nitrogen, or sulfur. The hydrocarbon group having a heteroatom means that some or all of the hydrogen and carbon atoms in the hydrocarbon group may be substituted with any of these heteroatoms. The unsaturated bond refers to, for example, a double bond between carbon and carbon, between carbon and oxygen, or between sulfur and oxygen, or a triple bond between carbon and carbon, between carbon and nitrogen, or the like. The hydrocarbon group having an unsaturated bond means that some or all of the carbon-hydrogen and carbon-carbon bonds in the hydrocarbon group may be substituted with any of these unsaturated bonds.

[0065] In the chemical formula (1), n ​​represents a valence number. For example, when M is a monovalent cation, n=1, when M is a divalent cation, n=2, and when M is a trivalent cation, n=3.

[0066] Specific examples of the phenoxide salt represented by the chemical formula (1) include lithium phenoxide, sodium phenoxide, potassium phenoxide, cesium phenoxide, triethylmethylammonium phenoxide, lithium 2-methylphenoxide, lithium 3-methylphenoxide, lithium 4-methylphenoxide, lithium 2-aminophenoxide, lithium 3-aminophenoxide, lithium 4-aminophenoxide, lithium 2-fluorophenoxide, lithium 3-fluorophenoxide, lithium 4-fluorophenoxide, and lithium Lithium 2-cyanophenoxide, Lithium 3-cyanophenoxide, Lithium 4-cyanophenoxide, Lithium 2-ethylphenoxide, Lithium 3-ethylphenoxide, Lithium 4-ethylphenoxide, Lithium 2,3-dimethylphenoxide, Lithium 2,4-dimethylphenoxide, Lithium 2,5-dimethylphenoxide, Lithium 2,6-dimethylphenoxide, Lithium 3,4-dimethylphenoxide, Lithium 5-amino-2-methylphenoxide, Lithium 2-amino-3-methylphenoxide, Lithium 6-amino-3-methylphenoxide oxide, lithium 4-amino-2-methylphenoxide, lithium 2-amino-4-methylphenoxide, lithium 4-amino-3-methylphenoxide, lithium 3-amino-4-methylphenoxide, lithium 3-methoxyphenoxide, lithium 2-methoxyphenoxide, lithium 4-methoxyphenoxide, lithium 4-fluoro-3-methylphenoxide, lithium 4-fluoro-2-methylphenoxide, lithium 3-fluoro-4-methylphenoxide, lithium 5-fluoro-2-methylphenoxide, lithium 2-mercaptophenoxide Cide, lithium 4-chlorophenoxide, lithium 2-chlorophenoxide, lithium 3-chlorophenoxide, lithium 2,6-difluorophenoxide, lithium 3,5-difluorophenoxide, lithium 3,4-difluorophenoxide, lithium 2,4-difluorophenoxide, lithium 2,3-difluorophenoxide, lithium 2,5-difluorophenoxide, lithium 2,3,4-trifluorophenoxide, lithium 2,3,6-trifluorophenoxide, lithium 3,4,5-trifluorophenoxide, lithium 2,3,5,6-tetrafluorophenoxide, lithium pentafluorophenoxide, lithium 2-allylphenoxide, lithium 4-allylphenoxide, lithium 2-acetylphenoxide, lithium 3-acetylphenoxide, lithium 4-acetylphenoxide, lithium 2,4,6-trimethylphenoxide, lithium 2-methylthiophenoxide, lithium 4-methylthiophenoxide, lithium 2-naphthoxide, lithium 1-naphthoxide, lithium 5,6,7,8-tetrahydro-2-naphthoxide, Lithium 5,6,7,8-tetrahydro-1-naphthoxide, lithium 3-tert-butylphenoxide, lithium 2-tert-butylphenoxide, lithium 4-tert-butylphenoxide, lithium 2-tert-amylphenoxide, lithium 4-tert-amylphenoxide, lithium 2-trifluoromethylphenoxide, lithium 4-trifluoromethylphenoxide, lithium 3-trifluoromethylphenoxide, lithium 3,5-dichlorophenoxide, lithium 3,4-dichlorophenoxide Lithium 2,4-dichlorophenoxide, lithium 2,5-dichlorophenoxide, lithium 2,6-dichlorophenoxide, lithium 3-phenylphenoxide, lithium 4-phenylphenoxide, lithium 2-phenylphenoxide, lithium 4-bromophenoxide, lithium 3-bromophenoxide, lithium 2-bromophenoxide, lithium 4-cyclohexylphenoxide, lithium 2-cyclohexylphenoxide, lithium 2-benzylphenoxide, lithium 4-benzylphenoxide diphenoxide, lithium 4-phenoxyphenoxide, lithium 3,4,5-trichlorophenoxide, lithium 2,4,6-trichlorophenoxide, lithium 3-iodophenoxide, lithium 2-iodophenoxide, lithium 4-iodophenoxide, lithium 4-(1-adamantyl)phenoxide, lithium 3,5-dibromophenoxide, lithium 2,6-dibromophenoxide, lithium 2,4-dibromophenoxide, lithium 2,4,6-tribromophenoxide, lithium 2,4,Examples of suitable phenoxide salts include lithium 6-triiodophenoxide and lithium 4-triphenylmethylphenoxide. However, the phenoxide salts are not limited to these compounds. The mechanism of action of phenoxide salts in electrolytes is unclear, but the following is theorized based on general facts. Bases such as alkoxides can be used to adjust the acidity of the electrolyte. However, when using strong bases such as alkoxides, side reactions with the organic solvent used in the electrolyte are a concern. On the other hand, phenoxides have a resonance structure within their molecular skeleton, making them less basic than alkoxides. This suppresses side reactions with organic solvents and prevents electrolyte degradation. Furthermore, the benzene skeleton, a component of phenoxides, has a resonance structure, making them thermodynamically stable and highly stable in electrochemical reactions. Therefore, it is speculated that the phenoxide anion stably interacts with the transition metal in the positive electrode active material, suppressing the elution of the transition metal into the electrolyte, thereby preventing capacity degradation.

[0067] Among the phenoxide salts exemplified above, lithium phenoxide and sodium phenoxide are particularly preferred since the presence of different metal ions can have adverse effects on metal ion secondary batteries.

[0068] The content of the component (A) is preferably within a range of 0.05 to 5 mass %, more preferably within a range of 0.07 to 3 mass %, and even more preferably within a range of 0.10 to 2 mass %, based on the total mass of the nonaqueous electrolyte. By setting the added amount to 0.05 mass % or more, and by further containing at least one component (B) described below as an additive, the cycle characteristics of the secondary battery in a high-temperature environment can be further improved. On the other hand, by setting the added amount to 5 mass % or less, a decrease in the solubility of the electrolyte in the nonaqueous electrolyte solvent can be suppressed.

[0069] In this embodiment, the non-aqueous electrolyte solution may contain at least one type of component (A), but the number of types of component (A) contained is preferably 1 to 5, more preferably 1 to 3, and particularly preferably 1 to 2. By reducing the number of types of component (A), the complexity of the process for producing the non-aqueous electrolyte solution can be reduced.

[0070] <Component (B)> The nonaqueous electrolyte solution of the present embodiment is required to further contain at least one component (B) described below as an additive in addition to the component (A), thereby improving cycle characteristics under high-temperature environments.

[0071] The component (B) is at least one compound selected from the group consisting of a boron complex salt represented by the following chemical formula (2), or a boric acid ester, an acid anhydride, a cyclic carbonate having an unsaturated bond, a cyclic carbonate having a halogen atom, a cyclic sulfonate ester, a cyclic sulfate ester, a cyclic sulfite ester, an amine having an acetoacetyl group represented by the following chemical formula (3), a phosphorus compound represented by any one of the following chemical formulas (4) to (6), a sulfonylimide salt, a sulfonate salt, and a dinitrile:

[0072] [Boron Complex Salt] The boron complex salt is specifically represented by the following chemical formula (2).

[0073]

[0074] In the chemical formula (2), M ｎ＋ As already explained, represents any one selected from the group consisting of a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an aluminum ion, a transition metal ion, and an onium ion, and therefore detailed explanation thereof will be omitted.

[0075] In the chemical formula (2), the X １ ~X ４are each independent and represent a combination of one or two arbitrarily selected groups forming a cyclic structure of -OOC-COO-, -OOCO-, -OOC-Y-COO-, -O-Y-O- or -OOC-Y-O-. In this case, Y represents a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10, more preferably 1 to 10 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10, more preferably 1 to 5 carbon atoms, and having a heteroatom, an unsaturated bond or a cyclic structure. １ ~X ４ has two sets of any one of the cyclic structures —OOC-Y-COO-, —O—Y—O-, and —OOC-Y—O-, each Y may be different. Here, the heteroatom means an oxygen atom, a nitrogen atom, or a sulfur atom.

[0076] The Y is not particularly limited, and examples thereof include linear alkylene groups such as methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, and nonylene groups, iodomethylene, diiodomethylene, bromomethylene, dibromomethylene, fluoromethylene, difluoromethylene, iodoethylene, 1,1-diiodoethylene, 1,2-diiodoethylene, triiodoethylene, tetraiodoethylene, chloroethylene, 1,1-dichloroethylene, 1,2-di ... and halogen-containing linear alkylene groups such as chloroethylene group, 1,2-dichloroethylene group, trichloroethylene group, tetrachloroethylene group, fluoroethylene group, 1,1-difluoroethylene group, 1,2-difluoroethylene group, trifluoroethylene group, and tetrafluoroethylene group; cyclic hydrocarbon groups such as cyclohexylene group, phenylene group, benzylene group, naphthylene group, anthracylene group, naphthasylene group, and pentasylene group; and cyclic hydrocarbon groups in which a part or all of the cyclic hydrocarbon groups have been substituted with halogen.

[0077] When Y is a 1,2-phenylene group, —O—Y—O— represents a benzenediolate group, and —O—Y—COO— represents a salicylate group.

[0078] In addition, the X １ ~X ４are each independently a halogen atom, an alkyl group having 1 to 20, preferably 1 to 10, more preferably 1 to 5, carbon atoms, an alkoxy group having 1 to 20, preferably 1 to 10, more preferably 1 to 5, carbon atoms, an alkyl group having 1 to 20, preferably 1 to 10, more preferably 1 to 5, carbon atoms and at least one of a halogen atom, a heteroatom, an unsaturated bond, or a cyclic structure, or an alkoxy group having 1 to 20, preferably 1 to 10, more preferably 1 to 5, carbon atoms and at least one of a halogen atom, a heteroatom, an unsaturated bond, or a cyclic structure. Here, the halogen atom refers to a fluorine atom, chlorine atom, bromine atom, or iodine atom. The heteroatom refers to an oxygen atom, nitrogen atom, or sulfur atom.

[0079] The X １ ~X ４Specific examples of the alkyl group include chain alkyl groups such as methyl, ethyl, propyl, butyl, isopropyl, pentyl, hexyl, heptyl, and octyl groups, cyclic alkyl groups such as cyclopentyl and cyclohexyl groups, iodomethyl, bromomethyl, chloromethyl, fluoromethyl, diiodomethyl, dibromomethyl, dichloromethyl, difluoromethyl, triiodomethyl, tribromomethyl, trichloromethyl, trifluoromethyl, 2-iodoethyl, 2-bromoethyl, 2-iodomethyl ... chain-containing halogen-containing alkyl groups such as 1-chloroethyl group, 2-fluoroethyl group, 1,2-diiodoethyl group, 1,2-dibromoethyl group, 1,2-dichloroethyl group, 1,2-difluoroethyl group, 2,2-diiodoethyl group, 2,2-dibromoethyl group, 2,2-dichloroethyl group, 2,2-difluoroethyl group, 2,2,2-tribromoethyl group, 2,2,2-trichloroethyl group, 2,2,2-trifluoroethyl group, and 1,1,1,3,3,3-hexafluoro-2-propyl group; 2-iodocyclohexyl group; cyclic halogen-containing alkyl groups such as bromocyclohexyl, 2-chlorocyclohexyl, and 2-fluorocyclohexyl; chain alkenyl groups such as 2-propenyl, isopropenyl, 2-butenyl, and 3-butenyl; cyclic alkenyl groups such as 2-cyclopentenyl, 2-cyclohexenyl, and 3-cyclohexenyl; chain alkynyl groups such as 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, and 4-pentynyl; phenyl, 3-methanyl, and 2-methyl-2-methylcyclohexyl; phenyl groups such as an oxyphenyl group, a 4-methoxyphenyl group, a 3,5-dimethoxyphenyl group, and a 4-phenoxyphenyl group; 2-iodophenyl group, a 2-bromophenyl group, a 2-chlorophenyl group, a 2-fluorophenyl group, a 3-iodophenyl group, a 3-bromophenyl group, a 3-chlorophenyl group, a 3-fluorophenyl group, a 4-iodophenyl group, a 4-bromophenyl group, a 4-chlorophenyl group, a 4-fluorophenyl group, a 3,5-diiodophenyl group, a 3,5-dibromophenyl group, a 3,5-dichlorophenyl group, a 3,Halogen-containing phenyl groups such as 5-difluorophenyl groups, chain alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, pentoxy and hexoxy groups, cyclic alkoxy groups such as cyclopentoxy and cyclohexoxy groups, 2-iodoethoxy, 2-bromoethoxy, 2-chloroethoxy, 2-fluoroethoxy, 1,2-diiodoethoxy, 1,2-dibromoethoxy, 1,2-dichloroethoxy, 1,2-difluoroethoxy, 2,2-diiodoethoxy, 2,2-dibromoethoxy, 2,2-dibromoethoxy, 2,2-dichloroethoxy, 2,2-difluoroethoxy, 2,2-diiodoethoxy, 2,2-dibromo ... chain-type halogen-containing alkyl groups such as 2-iodocyclohexoxy, 2-bromocyclohexoxy, 2-chlorocyclohexoxy, and 2-fluorocyclohexoxy; cyclic halogen-containing alkyl groups such as 2-iodocyclohexoxy, 2-bromocyclohexoxy, 2-chlorocyclohexoxy, and 2-fluorocyclohexoxy; 2-propenoxy, isopropenoxy, and 2-butene; chain alkenylalkoxy groups such as 2-cyclopentenoxy, 2-cyclohexenoxy, and 3-cyclohexenoxy groups; chain alkynylalkoxy groups such as 2-propynoxy, 1-butynoxy, 2-butynoxy, 3-butynoxy, 1-pentynoxy, 2-pentynoxy, 3-pentynoxy, and 4-pentynoxy groups; phenoxy groups such as phenoxy, 3-methylphenoxy, 4-methylphenoxy, and 3,5-dimethylphenoxy groups. , and halogen-containing phenoxy groups such as a 2-iodophenoxy group, a 2-bromophenoxy group, a 2-chlorophenoxy group, a 2-fluorophenoxy group, a 3-iodophenoxy group, a 3-bromophenoxy group, a 3-chlorophenoxy group, a 3-fluorophenoxy group, a 4-iodophenoxy group, a 4-bromophenoxy group, a 4-chlorophenoxy group, a 4-fluorophenoxy group, a 3,5-diiodophenoxy group, a 3,5-dibrophenoxy group, a 3,5-dichlorophenoxy group, and a 3,5-difluorophenoxy group.

[0080] The X １ ~X ４are independent of each other and may be the same or different. The functional groups exemplified above are merely examples and are not intended to limit the scope of the present invention.

[0081] Specific examples of the boron complex salt represented by the chemical formula (2) include lithium bisoxalatoborate, lithium bismalonatoborate, lithium bissalicylateborate, lithium bis[1,2'-bendiolato(2)-O,O']borate, lithium oxalatomalonatoborate, lithium oxalatosalicylateborate, lithium oxalato[1,2'-bendiolato(2)-O,O']borate, lithium diiodooxalatoborate, lithium dibromooxalatoborate, lithium dichlorooxalatoborate, and lithium Difluorooxalatoborate, Lithium iodochlorooxalatoborate, Lithium iodobromooxalatoborate, Lithium iodofluorooxalatoborate, Lithium bromochlorooxalatoborate, Lithium bromofluorooxalatoborate, Lithium chlorofluorooxalatoborate, Lithium diiodomalonatoborate, Lithium dibromomalonatoborate, Lithium dichloromalonatoborate, Lithium difluoromalonatoborate, Lithium iodochloromalonatoborate, Lithium iodobromomalonatoborate, Li Lithium iodofluoromalonatoborate, Lithium bromochloromalonatoborate, Lithium bromofluoromalonatoborate, Lithium chlorofluoromalonatoborate, Lithium diiodosalicylate borate, Lithium dibromosalicylate borate, Lithium dichlorosalicylate borate, Lithium difluorosalicylate borate, Lithium iodochlorosalicylate borate, Lithium iodobromosalicylate borate, Lithium iodofluorosalicylate borate, Lithium bromochlorosalicylate borate, Lithium bromide Bromofluorosalicylate borate, lithium chlorofluorosalicylate borate, lithium diiodo[1,2'-benziolate(2)-O,O']borate, lithium dibromo[1,2'-benziolate(2)-O,O']borate, lithium dichloro[1,2'-benziolate(2)-O,O']borate, lithium difluoro[1,2'-benziolate(2)-O,O']borate, lithium iodochloro[1,2'-benziolate(2)-O,O']borate, lithium iodobromo[1,2'-benziolate(2)-O,O']borate, lithium iodofluoro[1,2'-benziolate(2)-O,O']borate, lithium bromochloro[1,2'-benziolate(2)-O,O']borate, lithium bromofluoro[1,2'-benziolate(2)-O,O']borate, lithium chlorofluoro[1,2'-benziolate(2)-O,O']borate, lithium tetraiodoborate, lithium tetrabromoborate, lithium tetrachloroborate, lithium tetrafluoroborate, lithium iodotribromoborate, lithium iodotrichloroborate, lithium iodotrifluoroborate, lithium diiododibromoborate, lithium diiododichloroborate, lithium diiododifluoroborate, lithium triiodobromoborate, lithium triiodochloroborate, lithium triiodofluoroborate, lithium bromotrichloroborate, lithium bro Lithium trifluoroborate, lithium dibromodichloroborate, lithium dibromodifluoroborate, lithium tribromochloroborate, lithium tribromofluoroborate, lithium chlorotrifluoroborate, lithium dichlorodifluoroborate, lithium chlorotrifluoroborate, lithium iodobromochlorofluoroborate, lithium tetramethylborate, lithium tetraethylborate, lithium tetraphenylborate, lithium tetramethoxyborate, lithium tetraethoxyborate, lithium tetraphenoxyborate, lithium ethyldimethylphenylborate, lithium butylethylmethylphenylborate, lithium ethoxydimethoxyphenoxyborate, lithium dimethyloxalatoborate, lithium dimethylmalonatoborate, lithium dimethylsalicylateborate, lithium dimethyl[1,2'-bendiolato(2)-O,O'] borate, lithium ethylmethyl oxalatoborate, lithium phenylmethyl oxalatoborate, lithium iodomethyl oxalatoborate, lithium bromomethyl oxalatoborate, lithium chloromethyl oxalatoborate, lithium fluoromethyl oxalatoborate, lithium iodoethyl oxalatoborate, lithium bromoethyl oxalatoborate, lithium chloroethyl oxalatoborate, lithium fluoroethyl oxalatoborate, lithium ethoxymethoxy oxalatoborate, lithium iodomethoxy oxalatoborate, lithium bromomethoxy oxalatoborate, lithium chloromethoxy oxalatoborate, and lithium fluoromethoxy oxalatoborate.

[0082] Specific examples of the boron complex salt represented by the chemical formula (2) include sodium bisoxalatoborate, sodium bismalonatoborate, sodium bissalicylateborate, sodium bis[1,2'-bendiolato(2)-O,O']borate, sodium oxalatomalonatoborate, sodium oxalatosalicylateborate, sodium oxalato[1,2'-bendiolato(2)-O,O']borate, sodium diiodooxalatoborate, sodium dibromooxalatoborate, and sodium dichlorooxalatoborate. malonatoborate, sodium difluorooxalatoborate, sodium iodochlorooxalatoborate, sodium iodobromooxalatoborate, sodium iodofluorooxalatoborate, sodium bromochlorooxalatoborate, sodium bromofluorooxalatoborate, sodium chlorofluorooxalatoborate, sodium diiodomalonatoborate, sodium dibromomalonatoborate, sodium dichloromalonatoborate, sodium difluoromalonatoborate, sodium iodochloromalonatoborate , Sodium Iodobromomalonatoborate, Sodium Iodofluoromalonatoborate, Sodium Bromochloromalonatoborate, Sodium Bromofluoromalonatoborate, Sodium Chlorofluoromalonatoborate, Sodium Diiodosalicylate Borate, Sodium Dibromosalicylate Borate, Sodium Dichlorosalicylate Borate, Sodium Difluorosalicylate Borate, Sodium Iodochlorosalicylate Borate, Sodium Iodobromosalicylate Borate, Sodium Iodofluorosalicylate Borate, sodium bromochlorosalicylate borate, sodium bromofluorosalicylate borate, sodium chlorofluorosalicylate borate, sodium diiodo[1,2'-bendiolato(2)-O,O']borate, sodium dibromo[1,2'-bendiolato(2)-O,O']borate, sodium dichloro[1,2'-bendiolato(2)-O,O']borate, sodium difluoro[1,2'-bendiolato(2)-O,O']borate, sodium iodochloro[1,2'-bendiolato(2)-O,O']borate, sodium iodobromo[1,2'-bendiolato(2)-O,O']borate, lithium iodofluoro[1,2'-bendiolato(2)-O,O']borate, sodium bromochloro[1,2'-bendiolato(2)-O,O']borate, sodium bromofluoro[1,2'-bendiolato(2)-O,O']borate, sodium chlorofluoro[1,2'-bendiolato(2)-O,O']borate, sodium tetraiodoborate, sodium tetrabromoborate, sodium tetrachloroborate, sodium tetrafluoroborate, sodium iodotribromoborate, sodium iodotrichloroborate, sodium iodotrifluoroborate, sodium diiododibromoborate, sodium diiododichloroborate, sodium diiododifluoroborate, sodium triiodobromoborate, sodium triiodochloroborate, sodium triiodofluoroborate, sodium bro Mo trichloroborate, sodium bromotrifluoroborate, sodium dibromodichloroborate, sodium dibromodifluoroborate, sodium tribromochloroborate, sodium tribromofluoroborate, sodium chlorotrifluoroborate, sodium dichlorodifluoroborate, sodium chlorotrifluoroborate, sodium iodobromochlorofluoroborate, sodium tetramethylborate, sodium tetraethylborate, sodium tetraphenylborate, sodium tetramethoxyborate, sodium tetraethoxyborate, sodium tetraphenoxyborate, sodium ethyldimethylphenylborate, sodium butylethylmethylphenylborate, sodium ethoxydimethoxyphenoxyborate, sodium dimethyloxalatoborate, sodium dimethylmalonatoborate, sodium dimethylsalicylateborate, sodium dimethyl[1,2'-bendiolato(2)-O,O'] borate, sodium ethylmethyl oxalatoborate, sodium phenylmethyl oxalatoborate, sodium iodomethyl oxalatoborate, sodium bromomethyl oxalatoborate, sodium chloromethyl oxalatoborate, sodium fluoromethyl oxalatoborate, sodium iodoethyl oxalatoborate, sodium bromoethyl oxalatoborate, sodium chloroethyl oxalatoborate, sodium fluoroethyl oxalatoborate, sodium ethoxymethoxy oxalatoborate, sodium iodomethoxy oxalatoborate, sodium bromomethoxy oxalatoborate, sodium chloromethoxy oxalatoborate, sodium fluoromethoxy oxalatoborate,

[0083] Further, specific examples of the boron complex salt represented by the chemical formula (2) include triethylmethylammonium bisoxalatoborate, triethylmethylammonium bismalonatoborate, triethylmethylammonium bissalicylateborate, triethylmethylammonium bis[1,2'-bendiolato(2)-O,O']borate, triethylmethylammonium oxalatomalonatoborate, triethylmethylammonium oxalatosalicylateborate, triethylmethylammonium oxalato[1,2'-bendiolato(2)-O,O'] borate, triethylmethylammonium diiodooxalatoborate, triethylmethylammonium dibromooxalatoborate, triethylmethylammonium dichlorooxalatoborate, triethylmethylammonium difluorooxalatoborate, triethylmethylammonium iodochlorooxalatoborate, triethylmethylammonium iodobromooxalatoborate, triethylmethylammonium iodofluorooxalatoborate, triethylmethylammonium bromochlorooxalatoborate, triethylmethylammonium bromofluorooxalatoborate, triethylmethylammonium chlorofluorooxalatoborate, triethylmethylammonium diiodomalonatoborate, triethylmethylammonium dibromomalonatoborate, triethylmethylammonium dichloromalonatoborate, triethylmethylammonium difluoromalonatoborate, triethylmethylammonium iodochloromalonatoborate, triethylmethylammonium iodobromomalonatoborate, triethylmethylammonium iodofluoro Fluoromalonatoborate, triethylmethylammonium bromochloromalonatoborate, triethylmethylammonium bromofluoromalonatoborate, triethylmethylammonium chlorofluoromalonatoborate, triethylmethylammonium diiodosalicylate borate, triethylmethylammonium dibromosalicylate borate, triethylmethylammonium dichlorosalicylate borate, triethylmethylammonium difluorosalicylate borate, triethylmethylammonium iodochlorosalicylate Borate, triethylmethylammonium iodobromosalicylate borate, triethylmethylammonium iodofluorosalicylate borate, triethylmethylammonium bromochlorosalicylate borate, triethylmethylammonium bromofluorosalicylate borate, triethylmethylammonium chlorofluorosalicylate borate, triethylmethylammonium diiodo[1,2'-bendiolato(2)-O,O']borate, triethylmethylammonium dibromo[1,2'-bendiolato(2)-O,O']borate, triethylmethylammonium dichloro[1,2'-bendiolato(2)-O,O']borate, triethylmethylammonium difluoro[1,2'-bendiolato(2)-O,O']borate, triethylmethylammonium iodochloro[1,2'-bendiolato(2)-O,O']borate, triethylmethylammonium iodobromo[1,2'-bendiolato(2)-O,O']borate, triethylmethylammonium iodofluoro[1,2'-bendiolato(2)-O,O']borate, triethylmethylammonium bromochloro[1,2'-bendiolato(2)-O,O']borate, triethylmethylammonium bromofluoro[1,2'-bendiolato(2)-O,O']borate, triethylmethylammonium chlorofluoro[1,2'-bendiolato(2)-O,O'] borate, triethylmethylammonium tetraiodoborate, triethylmethylammonium tetrabromoborate, triethylmethylammonium tetrachloroborate, triethylmethylammonium tetrafluoroborate, triethylmethylammonium iodotribromoborate, triethylmethylammonium iodotrichloroborate, triethylmethylammonium iodotrifluoroborate, triethylmethylammonium diiododibromoborate, triethylmethylammonium diiododichloroborate, triethylmethylammonium diiododifluoroborate, triethylmethylammonium triiodobromoborate, triethylmethylammonium triiodochloroborate, triethylmethylammonium triiodofluoroborate, triethylmethylammonium bromotrichloroborate, triethylmethylammonium bromotrifluoroborate, triethylmethylammonium dibromodichloroborate, triethylmethylammonium dibromodifluoroborate, triethylmethylammonium tribromochloroborate, triethylmethylammonium Triethylmethylammonium tribromofluoroborate, triethylmethylammonium chlorotrifluoroborate, triethylmethylammonium dichlorodifluoroborate, triethylmethylammonium chlorotrifluoroborate, triethylmethylammonium iodobromochlorofluoroborate, triethylmethylammonium tetramethylborate, triethylmethylammonium tetraethylborate, triethylmethylammonium tetraphenylborate, triethylmethylammonium tetramethoxyborate, triethylmethylammonium tetraethoxyborate, triethylmethylammonium tetraphenoxyborate, triethylmethylethylammonium dimethylphenylborate, triethylmethylammonium butylethylmethylphenylborate, triethylmethylammonium ethoxydimethoxyphenoxyborate, triethylmethylammonium dimethyloxalatoborate, triethylmethylammonium dimethylmalonatoborate, triethylmethylammonium dimethylsalicylateborate, triethylmethylammonium dimethyl[1,2'-bendiolato(2)-O,O']borate, triethylmethylammonium ethylmethyloxalatoborate, triethylmethylammonium phenylmethyloxalatoborate, triethylmethylammonium iodomethyloxalatoborate, triethylmethylammonium bromomethyloxalatoborate, triethylmethylammonium chloromethyloxalatoborate, triethylmethylammonium fluoromethyloxalatoborate, triethylmethylammonium iodoethyloxalatoborate, triethylmethylammonium bromoethyloxalatoborate, triethylmethylammonium chloroethyloxalatoborate, triethylmethylammonium fluoroethyloxalatoborate, triethylmethylammonium ethoxymethoxyoxalatoborate, triethylmethylammonium iodomethoxyoxalatoborate, triethylmethylammonium bromomethoxyoxalatoborate, triethylmethylammonium chloromethoxyoxalatoborate, triethylmethylammonium fluoromethoxyoxalatoborate, and the like.

[0084] The specific examples of the boron complex salt represented by the chemical formula (2) shown above are merely examples, and the present embodiment is not limited to these.

[0085] From the viewpoint of availability, the boron complex salt is preferably lithium bisoxalatoborate, triethylmethylammonium bisoxalatoborate, lithium bissalicylateborate, lithium bis[1,2'-benziolate(2)-O,O']borate, or lithium difluorooxalatoborate.

[0086] In addition, the n in the chemical formula (2) represents the valence, as in the case of the chemical formula (1).

[0087] [Borate Ester] The borate ester is not particularly limited in type, and various borate esters can be selected as long as they do not impair the characteristics of the nonaqueous electrolyte solution of the present embodiment and the secondary battery using the same. Specific examples include trimethyl borate, triethyl borate, triisopropyl borate, tributyl borate, tripentyl borate, trihexyl borate, triheptyl borate, triphenyl borate, tris(2,2,2-iodoethyl) diborate, tris(2,2,2-tribromoethyl) borate, tris(2,2,2-trichloroethyl) borate, tris(2,2,2-trifluoroethyl) borate, tris(4-iodophenyl) borate, tris(4-bromophenyl) borate, tris(4-chlorophenyl) borate, tris(4-fluorophenyl) borate, diethylmethyl borate, and ethyldimethyl borate.

[0088] [Acid Anhydride] The acid anhydride is not particularly limited in type, and various types can be selected as long as it does not impair the characteristics of the nonaqueous electrolyte solution of the present embodiment and the secondary battery using the same. Specific examples include acetic anhydride, propionic anhydride, butyric anhydride, valeric anhydride, hexanoic anhydride, heptanoic anhydride, octanoic anhydride, nonanoic anhydride, decanoic anhydride, eicosanoic anhydride, docosanoic anhydride, benzoic anhydride, 4-methoxybenzoic anhydride, diphenylacetic anhydride, crotonic anhydride, cyclohexanecarboxylic anhydride, elaidic anhydride, isobutyric anhydride, isovaleric anhydride, lauric anhydride, linoleic anhydride, myristic anhydride, angelic anhydride, chrysocolla ... linear carboxylic acid anhydrides such as dichlorodifluoroacetic anhydride, trichloroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, and 4-trifluoromethylbenzoic anhydride, phthalic anhydride, 3-acetamidophthalic anhydride, 4,4'-carbonyldiphthalic anhydride, 4,4'-biphthalic anhydride, 3-iodophthalic anhydride, 3-bromophthalic anhydride, 3-chlorophthalic anhydride, 3-fluorophthalic anhydride, 4-iodophthalic anhydride, 4-bromophthalic anhydride, and 4-chlorophthalic anhydride; phthalic anhydride, 4-chlorophthalic anhydride, 4,5-diiodophthalic anhydride, 4,5-dibromophthalic anhydride, 4,5-dichlorophthalic anhydride, 4,5-difluorophthalic anhydride, 4,4'-sulfonyldiphthalic anhydride, 3-nitrophthalic anhydride, 4-nitrophthalic anhydride, exo-3,6-epoxyhexahydrophthalic anhydride, exo-3,6-epoxy-1,2,3,6-tetrahydrophthalic anhydride, tetraiodophthalic anhydride, tetrachlorophthalic anhydride, tetrafluorophthalic anhydride Acid anhydrides, 4-tert-butylphthalic anhydride, 4-ethynylphthalic anhydride, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride, succinic anhydride, (R)-(+)-2-acetoxysuccinic anhydride, (S)-(-)-2-acetoxysuccinic anhydride, 2-buten-1-ylsuccinic anhydride, butylsuccinic anhydride, decylsuccinic anhydride, 2,3-dimethylsuccinic anhydride, 2-dodecen-1-ylsuccinic anhydride, dodecylsuccinic anhydride, octadecene-ic anhydride, (2,7-octadien-1-yl)succinic anhydride, n-octylsuccinic anhydride, hexadecylsuccinic anhydride, maleic anhydride, 2,3-bis(2,4,5-trimethyl-3-thienyl)maleic anhydride, 2-(-2-carboxyethyl)-3-methyl-maleic anhydride, 2,3-dimethylmaleic anhydride, 2,3-diphenylmaleic anhydride, phenylmaleic anhydride, 4-pentene-1,2-dicarboxylic anhydride, 2,3-anthracenedicarboxylic anhydride, bicyclo[2,2,2]octo -5-ene-2,3-dicarboxylic anhydride, 4-bromo-1,8-naphthalenedicarboxylic anhydride, (±)-trans-1,2-cyclohexanedicarboxylic anhydride, cis-4-cyclohexene-1,2-dicarboxylic anhydride, 2,5-dibromo-3,4-thiophenedicarboxylic anhydride, 5,6-dihydro-1,4-dithiine-2,3-dicarboxylic anhydride, 2,2'-biphenyldicarboxylic anhydride, 4-methylcyclohexane-1,2-dicarboxylic anhydride, 3-methyl-4-cyclohexene-1 ,2-dicarboxylic anhydride, 4-methyl-4-cyclohexene-1,2-dicarboxylic anhydride, 2,3-naphthalenedicarboxylic anhydride, 3,4-thiophenedicarboxylic anhydride, 1,8-naphthalenedicarboxylic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, 1,2-cyclopropanedicarboxylic anhydride, glutaric anhydride, 3,3-pentamethyleneglutaric anhydride, 2,2-dimethylglutaric anhydride, 3,3-dimethylglutaric anhydride, 3-methylglutaric anhydride, 2-phthalimide Glutaric anhydride, 3,3-tetramethyleneglutaric anhydride, N-methylisatoic anhydride, 4-iodoisatoic anhydride, 4-bromoisatoic anhydride, 4-chloroisatoic anhydride, 4-fluoroisatoic anhydride, 5-iodoisatoic anhydride, 5-bromoisatoic anhydride, 5-chloroisatoic anhydride, 5-fluoroisatoic anhydride, itaconic anhydride, caronic anhydride, citraconic anhydride, diglycolic anhydride, 1,2-naphthalic anhydride, pyromellitic anhydride, HET anhydride, 2,2,3,3,4,Cyclic carboxylic acid anhydrides such as 4-hexafluoropentanedioic anhydride, linear sulfonic acid anhydrides such as trifluoromethanesulfonic acid anhydride and p-toluenesulfonic acid anhydride, cyclic sulfonic acid anhydrides such as 2-sulfobenzoic acid anhydride, tetraiodo-O-sulfobenzoic acid anhydride, tetrabromo-O-sulfobenzoic acid anhydride, tetrachloro-O-sulfobenzoic acid anhydride and tetrafluoro-O-sulfobenzoic acid anhydride, linear phosphinic acid anhydrides such as diphenylphosphinic acid, cyclic phosphonic acid anhydrides such as 1-propanephosphonic acid anhydride, 3,4-diiodophenylboronic acid anhydride, 3,4-dibromophenylboronic acid anhydride, 3,4-dichlorophenylboronic acid anhydride, 3,4-difluorophenylboronic acid anhydride Examples of acid anhydrides include 4-iodophenylboronic anhydride, 4-bromophenylboronic anhydride, 4-chlorophenylboronic anhydride, 4-fluorophenylboronic anhydride, (m-terphenylboronic anhydride, 3,4,5-triiodophenylboronic anhydride, 3,4,5-tribromophenylboronic anhydride, 3,4,5-trichlorophenylboronic anhydride, and 3,4,5-trifluorophenylboronic anhydride. Among these acid anhydrides, in the present embodiment, those having a cyclic structure are preferred, and those having an unsaturated bond in the molecule are also preferred. Note that maleic anhydride is particularly preferred as the acid anhydride from the viewpoints of availability and having a cyclic structure and an unsaturated bond in the molecule.

[0089] [Cyclic Carbonate Having Unsaturated Bonds] The type of cyclic carbonate having unsaturated bonds is not particularly limited, and various types can be selected as long as it does not impair the properties of the nonaqueous electrolyte solution of the present embodiment and the secondary battery using the same. The number of unsaturated bonds is preferably 1 to 10, more preferably 1 to 5, and particularly preferably 1 to 3. Specific examples of cyclic carbonates having an unsaturated bond include vinylene carbonate, iodovinylene carbonate, bromovinylene carbonate, chlorovinylene carbonate, fluorovinylene carbonate, 1,2-diiodovinylene carbonate, 1,2-dibromovinylene carbonate, 1,2-dichlorovinylene carbonate, 1,2-difluorovinylene carbonate, methylvinylene carbonate, iodomethylvinylene carbonate, bromomethylvinylene carbonate, chloromethylvinylene carbonate, fluoromethylvinylene carbonate, Examples of the cyclic carbonate include dichloromethyl vinylene carbonate, dibromomethyl vinylene carbonate, dichloromethyl vinylene carbonate, difluoromethyl vinylene carbonate, triiodomethyl vinylene carbonate, tribromomethyl vinylene carbonate, trichloromethyl vinylene carbonate, trifluoromethyl vinylene carbonate, ethyl vinylene carbonate, propyl vinylene carbonate, butyl vinylene carbonate, dimethyl vinylene carbonate, diethyl vinylene carbonate, dipropyl vinylene carbonate, vinyl ethylene carbonate, etc. Among the cyclic carbonates having an unsaturated bond, vinylene carbonate is preferred from the viewpoint of availability.

[0090] [Cyclic Carbonate Having Halogen Atoms] The cyclic carbonate having halogen atoms is not particularly limited in type, and various types can be selected as long as it does not impair the characteristics of the nonaqueous electrolyte solution of this embodiment and the secondary battery using the same. Here, halogen atoms refer to fluorine atoms, chlorine atoms, bromine atoms, or iodine atoms. Specific examples of cyclic carbonates having halogen atoms include iodoethylene carbonate, bromoethylene carbonate, chloroethylene carbonate, fluoroethylene carbonate, 1,2-diiodoethylene carbonate, 1,2-dibromoethylene carbonate, 1,2-dichloroethylene carbonate, and 1,2-difluoroethylene carbonate. From the viewpoint of availability, chloroethylene carbonate and fluoroethylene carbonate are preferred as the cyclic carbonate having an unsaturated bond.

[0091] [Cyclic Sulfonate Ester] The cyclic sulfonate ester is not particularly limited in type, and various cyclic sulfonates can be selected as long as they do not impair the characteristics of the nonaqueous electrolyte solution of the present embodiment and the secondary battery using the same. Specific examples of cyclic sulfonates include 1,3-propane sultone, 2,4-butane sultone, 1,4-butane sultone, and ethylene sulfite. From the viewpoint of availability, 1,3-propane sultone and ethylene sulfite are preferred as the cyclic sulfonate ester.

[0092] [Cyclic Sulfate] The cyclic sulfate is not particularly limited in type, and various types can be selected as long as they do not impair the characteristics of the nonaqueous electrolyte solution of the present embodiment and the secondary battery using the same. Specific examples of cyclic sulfate include ethylene sulfate.

[0093] [Cyclic Sulfite] The cyclic sulfite is not particularly limited in type, and various types can be selected as long as they do not impair the characteristics of the nonaqueous electrolyte solution of the present embodiment and the secondary battery using the same. Specific examples of cyclic sulfite include ethylene sulfite and 1,3-propylene sulfite.

[0094] [Amines Having an Acetoacetyl Group] The amines having an acetoacetyl group are specifically represented by the following chemical formula (3).

[0095]

[0096] The R ２ and R ３ each independently represents a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10, and more preferably 1 to 5 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10, and more preferably 1 to 5 carbon atoms, and having a halogen atom, a heteroatom, or an unsaturated bond. Here, the halogen atom refers to a fluorine atom, chlorine atom, bromine atom, or iodine atom. Furthermore, the heteroatom refers to an oxygen atom, nitrogen atom, or sulfur atom.

[0097] The R ２ and R ３is not particularly limited, and examples thereof include chain alkyl groups such as methyl group, ethyl group, propyl group, butyl group, isopropyl group, pentyl group, hexyl group, heptyl group, and octyl group; cyclic alkyl groups such as cyclopentyl group and cyclohexyl group; 2-iodoethyl group, 2-bromoethyl group, 2-chloroethyl group, 2-fluoroethyl group, 1,2-diiodoethyl group, 1,2-dibromoethyl group, 1,2-dichloroethyl group, 1,2-difluoroethyl group, 2,2-diiodoethyl group, 2,2-dibromoethyl group, chain halogen-containing alkyl groups such as 2-iodocyclohexyl, 2-bromocyclohexyl, 2-chlorocyclohexyl, 2-fluorocyclohexyl, and the like; chain halogen-containing alkyl groups such as 2-iodocyclohexyl, 2-bromocyclohexyl, 2-chlorocyclohexyl, and 2-fluorocyclohexyl; chain alkoxy groups such as 2-propenyl, isopropenyl, 2-butenyl, and 3-butenyl; cyclic alkenyl groups such as 2-cyclopentenyl, 2-cyclohexenyl, and 3-cyclohexenyl groups; chain alkynyl groups such as 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, and 4-pentynyl groups; phenyl groups such as phenyl, 3-methoxyphenyl, 4-methoxyphenyl, 3,5-dimethoxyphenyl, and 4-phenoxyphenyl groups; 2-iodophenyl, 2-bromophenyl, 2-chlorophenyl, and the like; Examples thereof include halogen-containing phenyl groups such as a phenyl group, a 2-fluorophenyl group, a 3-iodophenyl group, a 3-bromophenyl group, a 3-chlorophenyl group, a 3-fluorophenyl group, a 4-iodophenyl group, a 4-bromophenyl group, a 4-chlorophenyl group, a 4-fluorophenyl group, a 3,5-diiodophenyl group, a 3,5-dibromophenyl group, a 3,5-dichlorophenyl group, and a 3,5-difluorophenyl group; and naphthyl groups such as a 1-naphthyl group, a 2-naphthyl group, and a 3-amino-2-naphthyl group.

[0098] The R ２ and R ３are independent of each other and may be the same or different. The specific examples of the functional group group shown above are merely illustrative, and the present embodiment is not limited to these.

[0099] Specific examples of the compound represented by the chemical formula (3) include N,N-dimethylacetoacetamide, N,N-diethylacetoacetamide, N,N-dipropylacetoacetamide, N,N-dibutylacetoacetamide, N,N-ethylmethylacetoacetamide, N,N-methylpropylacetoacetamide, N,N-butylmethylacetoacetamide, etc. However, these specific examples of the compound are merely illustrative, and the present embodiment is not limited to these.

[0100] [Phosphorus Compound Represented by Chemical Formula (4)] Examples of the phosphorus compound include those represented by the following chemical formula (4).

[0101]

[0102] In the chemical formula (4), the M ｎ＋ As already explained, represents an alkali metal ion, alkaline earth metal ion, aluminum ion, transition metal ion, or onium ion. Similarly to the case of chemical formula (1), n ​​represents a valence. Therefore, detailed explanation of these will be omitted.

[0103] The above A １ and A ２ each independently represents an oxygen atom, a sulfur atom, or a selenium atom.

[0104] In the chemical formula (4), the X ５ and X ６ each independently represents a halogen atom, an alkyl group, or an alkyl group having at least one of a halogen atom, a heteroatom, or an unsaturated bond (hereinafter referred to as an "alkyl group having a halogen atom or the like"). The number of carbon atoms in the alkyl group and the alkyl group having a halogen atom or the like is in the range of 1 to 20, preferably 1 to 10, and more preferably 1 to 4. The number of unsaturated bonds is preferably in the range of 1 to 10, more preferably 1 to 5, and particularly preferably 1 to 3.

[0105] Specific examples of the alkyl group or alkyl group having a halogen atom or the like include chain alkyl groups such as methyl group, ethyl group, propyl group, butyl group, isopropyl group, pentyl group, hexyl group, heptyl group, and octyl group; cyclic alkyl groups such as cyclopentyl group and cyclohexyl group; 2-iodoethyl group, 2-bromoethyl group, 2-chloroethyl group, 2-fluoroethyl group, 1,2-diiodoethyl group, 1,2-dibromoethyl group, 1,2-dichloroethyl group, 1,2-difluoroethyl group; Chain halogen-containing alkyl groups such as diiodoethyl group, 2,2-dibromoethyl group, 2,2-dichloroethyl group, 2,2-difluoroethyl group, 2,2,2-tribromoethyl group, 2,2,2-trichloroethyl group, 2,2,2-trifluoroethyl group, and hexafluoro-2-propyl group; cyclic halogen-containing alkyl groups such as 2-iodocyclohexyl group, 2-bromocyclohexyl group, 2-chlorocyclohexyl group, and 2-fluorocyclohexyl group; 2-propenyl group, isopropenyl group, 2-butenyl group, 3- Chain alkenyl groups such as butenyl group; cyclic alkenyl groups such as 2-cyclopentenyl group, 2-cyclohexenyl group, and 3-cyclohexenyl group; chain alkynyl groups such as 2-propynyl group, 1-butynyl group, 2-butynyl group, 3-butynyl group, 1-pentynyl group, 2-pentynyl group, 3-pentynyl group, and 4-pentynyl group; phenyl groups such as phenyl group, 3-methoxyphenyl group, 4-methoxyphenyl group, 3,5-dimethoxyphenyl group, and 4-phenoxyphenyl group; 2-iodophenyl group, and 2-bromophenyl group halogen-containing phenyl groups such as a 2-chlorophenyl group, a 2-fluorophenyl group, a 3-iodophenyl group, a 3-bromophenyl group, a 3-chlorophenyl group, a 3-fluorophenyl group, a 4-iodophenyl group, a 4-bromophenyl group, a 4-chlorophenyl group, a 4-fluorophenyl group, a 3,5-diiodophenyl group, a 3,5-dibromophenyl group, a 3,5-dichlorophenyl group, and a 3,5-difluorophenyl group; and naphthyl groups such as a 1-naphthyl group, a 2-naphthyl group, and a 3-amino-2-naphthyl group.

[0106] The halogen atoms and heteroatoms are the same as those described in the chemical formula (1). In the alkyl group having a halogen atom or the like, the halogen atoms and heteroatoms may be such that some or all of the hydrogen atoms in the alkyl group are substituted with any of the halogen atoms and / or heteroatoms.

[0107] In addition, the X ５ and X ６ In the formula (I), either the alkyl group or the alkyl group having a halogen atom or the like may be bonded to each other to form a cyclic structure. ５ and X ６ Examples of the alkyl group or the alkyl group having a halogen atom or the like in the formula (I) include linear alkylene groups such as methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, and nonylene groups, iodomethylene, diiodomethylene, bromomethylene, dibromomethylene, fluoromethylene, difluoromethylene, iodoethylene, 1,1-diiodoethylene, 1,2-diiodoethylene, triiodoethylene, tetraiodoethylene, and chloroethylene groups, Examples thereof include halogen-containing linear alkylene groups such as 1,1-dichloroethylene group, 1,2-dichloroethylene group, trichloroethylene group, tetrachloroethylene group, fluoroethylene group, 1,1-difluoroethylene group, 1,2-difluoroethylene group, trifluoroethylene group, and tetrafluoroethylene group; cyclic hydrocarbon groups such as cyclohexylene group, phenylene group, benzylene group, naphthylene group, anthracylene group, naphthasylene group, and pentasylene group; and groups in which a part or all of these groups have been replaced with a halogen atom or the like.

[0108] The X ５ and X ６ The functional groups exemplified above may be the same or different from each other. The functional groups exemplified above are merely examples and are not intended to be limiting.

[0109] Specific examples of the phosphorus compound represented by the chemical formula (4) include lithium diiodophosphate, lithium dibromophosphate, lithium dichlorophosphate, lithium difluorophosphate, sodium diiodophosphate, sodium dibromophosphate, sodium dichlorophosphate, sodium difluorophosphate, potassium diiodophosphate, potassium dibromophosphate, potassium dichlorophosphate, and potassium difluorophosphate.

[0110] [Phosphorus Compound Represented by Chemical Formula (5)] Next, the phosphorus compound represented by the following chemical formula (5) will be described. However, the description of the same compounds as those described in the phosphorus compound represented by the chemical formula (4) will be omitted.

[0111]

[0112] In the chemical formula (5), the M ｎ＋ and the valence n is the same as that described in the chemical formula (4).

[0113] In the chemical formula (5), the X ７ ~X １２ each independently represents a halogen atom, an alkyl group, an alkoxy group, an alkylthio group, an alkyl group having at least one of a halogen atom, a heteroatom, or an unsaturated bond (hereinafter referred to as an "alkyl group having a halogen atom or the like"); an alkoxy group having at least one of a halogen atom, a heteroatom, or an unsaturated bond (hereinafter referred to as an "alkoxy group having a halogen atom or the like"); or an alkylthio group having at least one of a halogen atom, a heteroatom, or an unsaturated bond (hereinafter referred to as an "alkylthio group having a halogen atom or the like"). The number of carbon atoms in the alkyl group, alkoxy group, alkylthio group, alkyl group having a halogen atom or the like, alkoxy group having a halogen atom or the like, and alkylthio group having a halogen atom or the like is in the range of 1 to 20, preferably 1 to 10, and more preferably 1 to 4. The number of unsaturated bonds is preferably in the range of 1 to 10, more preferably 1 to 5, and particularly preferably 1 to 3.

[0114] The halogen atoms and heteroatoms are the same as those described in the chemical formula (1). In the alkyl group having a halogen atom or the like, the alkoxy group having a halogen atom or the like, and the alkylthio group having a halogen atom or the like, the halogen atoms and heteroatoms may be such that some or all of the hydrogen atoms in these functional groups are substituted with any of these halogen atoms and / or heteroatoms.

[0115] The X ７ ~X １２Specific examples of the alkyl group include chain alkyl groups such as methyl, ethyl, propyl, butyl, isopropyl, pentyl, hexyl, heptyl, and octyl groups, cyclic alkyl groups such as cyclopentyl and cyclohexyl groups, iodomethyl, bromomethyl, chloromethyl, fluoromethyl, diiodomethyl, dibromomethyl, dichloromethyl, difluoromethyl, triiodomethyl, tribromomethyl, trichloromethyl, trifluoromethyl, 2-iodoethyl, 2-bromoethyl, 2-iodomethyl ... chain-containing halogen-containing alkyl groups such as 1-chloroethyl group, 2-fluoroethyl group, 1,2-diiodoethyl group, 1,2-dibromoethyl group, 1,2-dichloroethyl group, 1,2-difluoroethyl group, 2,2-diiodoethyl group, 2,2-dibromoethyl group, 2,2-dichloroethyl group, 2,2-difluoroethyl group, 2,2,2-tribromoethyl group, 2,2,2-trichloroethyl group, 2,2,2-trifluoroethyl group, and 1,1,1,3,3,3-hexafluoro-2-propyl group; 2-iodocyclohexyl group; cyclic halogen-containing alkyl groups such as bromocyclohexyl, 2-chlorocyclohexyl, and 2-fluorocyclohexyl; chain alkenyl groups such as 2-propenyl, isopropenyl, 2-butenyl, and 3-butenyl; cyclic alkenyl groups such as 2-cyclopentenyl, 2-cyclohexenyl, and 3-cyclohexenyl; chain alkynyl groups such as 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-pentynyl, 2-pentynyl, 3-pentynyl, and 4-pentynyl; phenyl, 3-methanyl, and 2-methyl-2-methylcyclohexyl; phenyl groups such as an oxyphenyl group, a 4-methoxyphenyl group, a 3,5-dimethoxyphenyl group, and a 4-phenoxyphenyl group; 2-iodophenyl group, a 2-bromophenyl group, a 2-chlorophenyl group, a 2-fluorophenyl group, a 3-iodophenyl group, a 3-bromophenyl group, a 3-chlorophenyl group, a 3-fluorophenyl group, a 4-iodophenyl group, a 4-bromophenyl group, a 4-chlorophenyl group, a 4-fluorophenyl group, a 3,5-diiodophenyl group, a 3,5-dibromophenyl group, a 3,5-dichlorophenyl group, a 3,Halogen-containing phenyl groups such as 5-difluorophenyl groups, chain alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, pentoxy and hexoxy groups, cyclic alkoxy groups such as cyclopentoxy and cyclohexoxy groups, 2-iodoethoxy, 2-bromoethoxy, 2-chloroethoxy, 2-fluoroethoxy, 1,2-diiodoethoxy, 1,2-dibromoethoxy, 1,2-dichloroethoxy, 1,2-difluoroethoxy, 2,2-diiodoethoxy, 2,2-dibromoethoxy, 2,2-dichloroethoxy, chain-containing halogen-containing alkyl groups such as a 2,2-difluoroethoxy group, a 2,2,2-tribromoethoxy group, a 2,2,2-trichloroethoxy group, a 2,2,2-trifluoroethoxy group, and a 1,1,1,3,3,3-hexafluoro-2-propoxy group; cyclic halogen-containing alkyl groups such as a 2-iodocyclohexoxy group, a 2-bromocyclohexoxy group, a 2-chlorocyclohexoxy group, and a 2-fluorocyclohexoxy group; chain-containing alkenylalkoxy groups such as a 2-propenoxy group, an isopropenoxy group, a 2-butenoxy group, and a 3-butenoxy group; Cyclic alkenylalkoxy groups such as cyclopentenoxy, 2-cyclohexenoxy, and 3-cyclohexenoxy groups; chain alkynylalkoxy groups such as 2-propynoxy, 1-butynoxy, 2-butynoxy, 3-butynoxy, 1-pentynoxy, 2-pentynoxy, 3-pentynoxy, and 4-pentynoxy groups; phenoxy groups such as 3-methylphenoxy, 4-methylphenoxy, and 3,5-dimethylphenoxy groups; 2-iodophenoxy, 2-bromophenoxy, 2-chlorophenoxy, and 2-fluorophenoxy groups. halogen-containing phenoxy groups such as a 3-iodophenoxy group, a 3-bromophenoxy group, a 3-chlorophenoxy group, a 3-fluorophenoxy group, a 4-iodophenoxy group, a 4-bromophenoxy group, a 4-chlorophenoxy group, a 4-fluorophenoxy group, a 3,5-diiodophenoxy group, a 3,5-dibrophenoxy group, a 3,5-dichlorophenoxy group, or a 3,5-difluorophenoxy group; and alkylthio groups such as a methylthio group, an ethylthio group, a propylthio group, a butylthio group, an isopropylthio group, a pentylthio group, or a hexylthio group.

[0116] In addition, the X ７ ~X １２ At least one arbitrarily selected combination of X may form any of the cyclic structures of -OOC-COO-, -OOCO-, -OOC-Z-COO-, -OOC-Z-O-, and -O-Z-O-. ７ ~X １２ When two or more cyclic structures are formed, the cyclic structures may be the same or different. Furthermore, Z represents a hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and at least one of a halogen atom, a heteroatom, an unsaturated bond, or a cyclic structure. Furthermore, the number of unsaturated bonds is preferably in the range of 1 to 10, more preferably in the range of 1 to 5, and particularly preferably in the range of 1 to 3.

[0117] Z is not particularly limited, and specific examples thereof include linear alkylene groups such as methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, and nonylene groups, iodomethylene, diiodomethylene, bromomethylene, dibromomethylene, fluoromethylene, difluoromethylene, iodoethylene, 1,1-diiodoethylene, 1,2-diiodoethylene, triiodoethylene, tetraiodoethylene, chloroethylene, and 1,1-diiodoethylene. and halogen-containing linear alkylene groups such as 1,1-dichloroethylene group, 1,2-dichloroethylene group, trichloroethylene group, tetrachloroethylene group, fluoroethylene group, 1,1-difluoroethylene group, 1,2-difluoroethylene group, trifluoroethylene group, and tetrafluoroethylene group; cyclic hydrocarbon groups such as cyclohexylene group, phenylene group, benzylene group, naphthylene group, anthracylene group, naphthasylene group, and pentasylene group; and groups in which a part or all of these groups have been substituted with halogen.

[0118] When Z is a 1,2-phenylene group, —O—Z—O— represents a benzenediolate group, and —O—Z—COO— represents a salicylate group.

[0119] Specific examples of the phosphorus compound represented by the chemical formula (5) include lithium difluorobisoxalate phosphate, sodium difluorobisoxalate phosphate, lithium tetrafluorooxalate phosphate, and sodium tetrafluorooxalate phosphate.

[0120] [Phosphorus Compound Represented by Chemical Formula (6)] Next, the phosphorus compound represented by the following chemical formula (6) will be described. However, the description of the same compounds as those described in the phosphorus compound represented by the chemical formula (4) will be omitted.

[0121]

[0122] In the chemical formula (6), the M ｎ＋ and the valence n is the same as that described in the chemical formula (4).

[0123] In the chemical formula (6), the R ４ and R ５ each independently represents a hydrocarbon group or a hydrocarbon group having at least one of a halogen atom, a hetero atom, or an unsaturated bond (hereinafter referred to as a "hydrocarbon group having a halogen atom or the like"). The hydrocarbon group has 1 to 20 carbon atoms, preferably 1 to 10, and more preferably 1 to 4. The hydrocarbon group having a halogen atom or the like has 1 to 20 carbon atoms, preferably 1 to 10, and more preferably 1 to 4. The number of unsaturated bonds is preferably in the range of 1 to 10, more preferably 1 to 5, and particularly preferably 1 to 3.

[0124] Specific examples of the hydrocarbon group or hydrocarbon group having a halogen atom or the like include chain alkyl groups such as methyl, ethyl, propyl, butyl, isopropyl, pentyl, hexyl, heptyl, and octyl groups; cyclic alkyl groups such as cyclopentyl and cyclohexyl groups; 2-iodoethyl, 2-bromoethyl, 2-chloroethyl, 2-fluoroethyl, 1,2-diiodoethyl, 1,2-dibromoethyl, 1,2-dichloroethyl, 1,2-difluoroethyl, 2,2-diiodoethyl, and the like. chain halogen-containing alkyl groups such as 2-iodoethyl group, 2,2-dibromoethyl group, 2,2-dichloroethyl group, 2,2-difluoroethyl group, 2,2,2-tribromoethyl group, 2,2,2-trichloroethyl group, 2,2,2-trifluoroethyl group, and 1,1,1,3,3,3-hexafluoro-2-propyl group; cyclic halogen-containing alkyl groups such as 2-iodocyclohexyl group, 2-bromocyclohexyl group, 2-chlorocyclohexyl group, and 2-fluorocyclohexyl group; 2-propenyl group, isopropenyl group, and 2-butene group; chain alkenyl groups such as a 2-cyclopentenyl group, a 2-cyclohexenyl group, and a 3-cyclohexenyl group; chain alkynyl groups such as a 2-propynyl group, a 1-butynyl group, a 2-butynyl group, a 3-butynyl group, a 1-pentynyl group, a 2-pentynyl group, a 3-pentynyl group, and a 4-pentynyl group; phenyl groups such as a phenyl group, a 3-methoxyphenyl group, a 4-methoxyphenyl group, a 3,5-dimethoxyphenyl group, and a 4-phenoxyphenyl group; 2-iodophenyl group, 2-bromophenyl group, and a 2-bromophenyl group; halogen-containing phenyl groups such as a 1-naphthyl group, a 2-naphthyl group, a 3-amino-2-naphthyl group, a 3-amino-2-naphthyl group, a 1 ...

[0125] The halogen atoms and hetero atoms are the same as those described in the chemical formula (1). In the hydrocarbon group having a halogen atom or the like, the halogen atoms and hetero atoms may be such that some or all of the hydrogen atoms in the hydrocarbon group are substituted with any of these halogen atoms and / or hetero atoms.

[0126] The R ４ and R ５ The functional groups exemplified above may be the same or different from each other. The functional groups exemplified above are merely examples and are not intended to be limiting.

[0127] Furthermore, the R ４ and R ５ are either the hydrocarbon groups or the hydrocarbon groups having halogen atoms or the like, and may be bonded to each other to form a cyclic structure. In this case, specific examples of the hydrocarbon groups or hydrocarbon groups having halogen atoms or the like include linear alkylene groups such as methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, and nonylene groups, iodomethylene, diiodomethylene, bromomethylene, dibromomethylene, fluoromethylene, difluoromethylene, iodoethylene, 1,1-diiodoethylene, 1,2-diiodoethylene, triiodoethylene, tetraiodoethylene, and chloroethylene. Examples of such alkylene groups include halogen-containing linear alkylene groups such as ethylene, 1,1-dichloroethylene, 1,2-dichloroethylene, trichloroethylene, tetrachloroethylene, fluoroethylene, 1,1-difluoroethylene, 1,2-difluoroethylene, trifluoroethylene, and tetrafluoroethylene; cyclic hydrocarbon groups such as cyclohexylene, phenylene, benzylene, naphthylene, anthracylene, naphthasylene, and pentasylene; and groups in which a part or all of these groups have been replaced with a halogen atom or the like.

[0128] Specific examples of the phosphorus compound represented by the chemical formula (6) include lithium diethyl phosphate and lithium bis(2,2,2-trifluoroethyl)phosphate.

[0129] [Sulfonylimide Salts] The sulfonylimide salts are not particularly limited in type, and various types can be selected as long as they do not impair the properties of the nonaqueous electrolyte solution of the present embodiment and the secondary battery using the same. Specific examples of sulfonylimide salts include lithium bis(fluorosulfonyl)imide and lithium bis(trifluoromethanesulfonyl)imide.

[0130] [Sulfonate] The sulfonate is not particularly limited in type, and various sulfonates can be selected as long as they do not impair the characteristics of the nonaqueous electrolyte solution of the present embodiment and the secondary battery using the same. Specific examples of sulfonates include lithium fluorosulfonate, lithium methanesulfonate, and lithium trifluoromethanesulfonate.

[0131] [Dinitriles] The dinitriles are not particularly limited in type, and various types can be selected as long as they do not impair the properties of the nonaqueous electrolyte solution of the present embodiment and the secondary battery using the same. Specific examples of dinitriles include succinonitrile, fumaronitrile, and adiponitrile.

[0132] The content of the component (B) is preferably within a range of 0.05 to 5 mass %, more preferably within a range of 0.07 to 3 mass %, and particularly preferably within a range of 0.10 to 2 mass %, based on the total mass of the nonaqueous electrolyte. By setting the added amount to 0.05 mass % or more, at least one component (A) can be further added as an additive, thereby further improving the cycle characteristics of the secondary battery under high-temperature environments. On the other hand, by setting the added amount to 5 mass % or less, a decrease in the solubility of the electrolyte in the nonaqueous electrolyte solvent can be suppressed.

[0133] In this embodiment, the non-aqueous electrolyte solution may contain at least one type of component (B), but the number of types of component (B) contained is preferably 1 to 5, more preferably 1 to 3, and particularly preferably 1 to 2. By reducing the number of types of component (B), the complexity of the process for producing the non-aqueous electrolyte solution can be reduced.

[0134] <Electrolyte> A conventionally known electrolyte can be used as the electrolyte, and the cation constituting the salt of the electrolyte may be appropriately selected depending on the type of nonaqueous secondary battery. For example, lithium ions are used in the case of lithium ion secondary batteries, sodium ions are used in the case of sodium ion secondary batteries, potassium ions are used in the case of potassium ion secondary batteries, magnesium ions are used in the case of magnesium ion secondary batteries, and calcium ions are used in the case of calcium ion secondary batteries.

[0135] The anion constituting the salt of the electrolyte preferably contains a fluorine-containing anion. Specific examples of such fluorine-containing anions include BF. ４ － , P.F. ６ － , B.F. ３ CF ３ － , B.F. ３ C ２ F ５ － , C.F. ３ SO ３ － , C ２ F ５ SO ３ － , C ３ F ７ SO ３ － , C ４ F ９ SO ３ － , N(SO ２ F) ２ － , N(CF ３ SO ２ ) ２ －, N(C ２ F ５ SO ２ ) ２ － , N(CF ３ SO ２ ) (CF ３ CO) － , N(CF ３ SO ２ ) (C ２ F ５ SO ２ ) － , C(CF ３ SO ２ ) ３ － These may be used alone or in combination of two or more. Among the fluorine-containing anions, BF is preferred from the viewpoint of improving the safety and stability of the non-aqueous electrolyte, electrical conductivity, and cycle characteristics. ４ － , P.F. ６ － , N(SO ２ F) ２ － , N(CF ３ SO ２ ) ２ － is preferred, and BF ４ － , P.F. ６ － , N(SO ２ F) ２ － is particularly preferred.

[0136] The concentration of the electrolyte relative to the organic solvent is not particularly limited, and is usually 0.1 to 4.0 M, preferably 0.2 to 2.0 M, more preferably 0.2 to 1.5 M, and particularly preferably 0.3 to 1.2 M. By setting the concentration to 0.1 M or more, it is possible to prevent the electrical conductivity of the non-aqueous electrolyte from becoming insufficient. On the other hand, by setting the concentration to 4.0 M or less, it is possible to suppress a decrease in electrical conductivity due to an increase in the viscosity of the non-aqueous electrolyte, and to prevent a decrease in secondary battery performance.

[0137] <Organic Solvent> The organic solvent (nonaqueous solvent) used in the nonaqueous electrolyte solution is not particularly limited, and examples thereof include cyclic carbonate esters, chain carbonate esters, phosphate esters, cyclic ethers, chain ethers, fluorinated ethers, lactone compounds, chain esters, nitrile compounds, amide compounds, sulfone compounds, ionic liquids, etc. Among these organic solvents, carbonate esters are preferred because they are commonly used as organic solvents for lithium secondary batteries.

[0138] The cyclic carbonate ester is not particularly limited, and examples thereof include ethylene carbonate, propylene carbonate, butylene carbonate, etc. Of these, cyclic carbonates such as ethylene carbonate and propylene carbonate are preferred from the viewpoint of improving the charging efficiency of lithium secondary batteries. The chain carbonate ester is not particularly limited, and examples thereof include dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, etc. Of these, dimethyl carbonate and ethyl methyl carbonate are preferred from the viewpoint of improving the charging efficiency of lithium secondary batteries. The phosphate ester is not particularly limited, and examples thereof include trimethyl phosphate, triethyl phosphate, ethyl dimethyl phosphate, diethyl methyl phosphate, tris(2,2,2-trifluoroethyl)phosphate, tris(2,2,3,3-tetrafluoropropyl)phosphate, tris(2,2,3,3,3-pentafluoropropyl)phosphate, dimethyl(2,2,2-trifluoroethyl)phosphate, methyl bis(2,2,2-trifluoroethyl)phosphate, dimethyl(2,2,3,3-tetrafluoropropyl)phosphate, methyl bis(2,2,3,3-tetrafluoropropyl)phosphate, diethyl(2,2,2-trifluoroethyl)phosphate, ethyl bis(2,2,2-trifluoroethyl)phosphate, diethyl(2,2,3,3-tetrafluoropropyl)phosphate, and ethyl bis(2,2,3,3-tetrafluoropropyl)phosphate. The cyclic ether is not particularly limited, and examples thereof include tetrahydrofuran, 2-methyltetrahydrofuran, etc. The chain ether is not particularly limited, and examples thereof include dimethoxyethane, etc.The fluorinated ether is not particularly limited, and examples thereof include methyl 1,1,2,2-tetrafluoroethyl ether, ethyl 1,1,2,2-tetrafluoroethyl ether, 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether, 1,1,2,2-tetrafluoroethyl 2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether, 2,2,3,3,3-pentafluoropropyl-1,1,2,2-tetrafluoroethyl ether, methyl 2,2,3,3,3-pentafluoropropyl ether, difluoromethyl-2,2,3,3-tetrafluoropropyl ether, methyl 1,1,2,3,3,3-hexafluoropropyl ether, and ethyl 1,1,2,3,3,3-hexafluoropropyl ether. hexafluoroisopropyl ether, methyl nonafluorobutyl ether, ethyl nonafluorobutyl ether, 2,2-difluoroethyl-1,1,2,2-tetrafluoroethyl ether, bis(2,2,2-trifluoroethyl)ether, hexafluoroisopropyl methyl ether, fluoromethyl-1,1,1,3,3,3-hexafluoroisopropyl ether, 1,1,2,3,3,3-hexafluoropropyl-2,2-difluoroethyl ether, 1,1,2,3,3,3-hexafluoropropyl-2,2,2-trifluoroethyl ether, bis(2,2-difluoroethyl)ether, bis(2,2,3,3-tetrafluoropropyl)ether, bis(2,2,3,3-tetrafluoropropyl)ether, bis(2,2,3,3,3-pentafluoropropyl)ether, etc. The lactone compound is not particularly limited, and examples thereof include γ-butyrolactone, etc. The chain ester is not particularly limited, and examples thereof include methyl propionate, methyl acetate, ethyl acetate, and methyl formate. The nitrile compound is not particularly limited, and examples thereof include acetonitrile. The amide compound is not particularly limited, and examples thereof include dimethylformamide. The sulfone compound is not particularly limited, and examples thereof include sulfolane and methylsulfolane.The ionic liquid is not particularly limited, and examples thereof include 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(fluorosulfonyl)imide, and 1-methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide. Organic solvents in which at least some of the hydrogen atoms in the hydrocarbon groups contained in the organic solvent molecules have been substituted with fluorine can also be suitably used. These organic solvents may be used alone or in combination of two or more.

[0139] As the organic solvent, it is preferable to use a carbonate ester from the viewpoint of availability and performance.

[0140] <Others> The nonaqueous electrolyte solution according to the present embodiment may contain other additives that are conventionally known. In this case, the amount of the other additives added can be set appropriately as needed.

[0141] (Secondary Battery) Next, a lithium ion secondary battery will be described as an example of the secondary battery of the present invention. Fig. 1 is a cross-sectional view showing a schematic outline of a lithium ion secondary battery provided with the non-aqueous electrolyte solution.

[0142] As shown in FIG. 1 , the lithium-ion secondary battery according to this embodiment has a structure in which a stack of a positive electrode 1, a separator 3, a negative electrode 2, and a spacer 7 is housed in an internal space formed by a positive electrode can 4 and a negative electrode can 5, in this order from the positive electrode can 4 side. A spring 8 is interposed between the negative electrode can 5 and the spacer 7, thereby appropriately pressing and fixing the positive electrode 1 and the negative electrode 2. A nonaqueous electrolyte containing the compound group of component (A) and component (B) according to this embodiment is impregnated between the positive electrode 1, the separator 3, and the negative electrode 2. The positive electrode can 4 and the negative electrode can 5 are sandwiched with a gasket 6 interposed between them to join them and seal the stack.

[0143] The material of the positive electrode active material in the positive electrode 1 is not particularly limited, and in the case of a lithium ion secondary battery, for example, a transition metal compound having a structure in which lithium ions can diffuse, or an oxide of the transition metal compound and lithium, can be mentioned. Specifically, LiCoO ２ , LiNiO ２ , LiMn ２ O ４ , Li ２ MnO ３ + LiMeO ２ (Me=at least one metal element selected from Mn, Co, Ni, and Fe) Solid solution, LiFePO ４ , LiCoPO ４ , LiMnPO ４ , Li ３ V ２ (P.O. ４ ) ３ , Li ２ MeP.O. ４ F (Me=Fe, Co), LiVPO ４ F, Li ２ MeSiO ４ (Me=at least one metal element selected from Fe, Mn, and Co), FeCoOF, LiCo ｘ Me ｙ O ２ (0<x<1, 0<y<1, x+y=1, Me=at least one metal element selected from Sn, Mg, Al, Fe, Zr, V, Ga, Zn, Cu, Ni, Mn, Ti, Zr, and Cr.), Li (Li ａ Me ｙ Mn ｚ ) O ２ (0<a≦0.2, 0<y≦0.6, 0<z≦0.6, x+y+z=1, Me=at least one metal element selected from Al, Ti, Cr, Ni, and Co.), Li (Li ａ Me ｘ Mn ｙ ) O ｚ F ｂ (0<a≦0.2, 0<b≦1, 0<x≦0.6, 0<y≦0.6, 0<z<4, a+x+y=2, b+z=4, Me=at least one metal element selected from Al, Ti, Cr, Ni, Co, Fe, and Mg.), LiMe ｘ Mnｙ O ４ (0<x<2, 0<y<2, x+y=2, Me=at least one metal element selected from the group consisting of Cr, Fe, Co, Ni, Mg, Cu, Ti, and Al.), LiNi ｘ Mn ｙ O2 (0<x<1, 0<y<1, x+y=1), Li (LiaNi ｘ Co ｙ Mn ｚ ) O ２ (0≦a≦0.2, 0<x<1, 0<y<1, 0<z<1, a+x+y+z=1), LiNi ｘ CoyAl ｚ O ２ (0<x<1, 0<y<1, 0<z<1, x+y+z=1), LiFeF ３ , LiMeBO ３ (Me=at least one metal element selected from Mn and Fe), TiO ２ , V ２ O ５ , MoO ３ , Cr ３ O ８ , W.O. ３ oxides such as MnS ２ , TiS ２ , FeS, MoS ２ or conductive polymers such as polyacetylene, polyparaphenylene, polyaniline, polypyrrole, polythiophene, polyacene, and dimercaptothiadiazole, organic sulfur-based materials such as organic disulfides, carbon sulfides, and activated sulfur, activated carbon, radical-generating polymers, and carbon materials. Of the positive electrode active materials exemplified above, binary transition metal oxides and ternary transition metal oxides are preferred in this embodiment.

[0144] The binary transition metal oxide is not particularly limited, and examples thereof include LiNi ｘ１ Co ｙ１ O ｚ１(0<x1<2, 0<y1<2, 2≦z1≦4, 1≦x1+y1≦2), LiNix2Mny2Oz2 (0<x2<2, 0<y2<2, 2≦z2≦4, 1≦x2+y2≦2), LiCox3Mny3Oz3 (0<x3<2, 0<y3<2, 2≦z3≦4, 1≦x3+y3≦2), etc. In these binary transition metal oxides, part of the oxygen may be replaced with other non-metal ions such as phosphate, borate, or fluorine.

[0145] The LiNi ｘ１ Co ｙ１ O ｚ１ , and LiNi ｘ２ Mn ｙ２ O ｚ２ In the binary transition metal oxide comprising the above formula, x1 and x2 represent the composition ratio of nickel in the binary transition metal oxide. x1 and x2 are each greater than 0 and less than 2, preferably greater than 0.1 and less than 1.9, and more preferably greater than 0.5 and less than 1.5. x1 and x2 can be controlled by adjusting the amount of nickel supplied during the production of the positive electrode active material. Furthermore, y1 represents the composition ratio of cobalt in the binary transition metal oxide. y1 is greater than 0 and less than 2, preferably greater than 0.1 and less than 1.9, and more preferably greater than 0.5 and less than 1.5. y1 can be controlled by adjusting the amount of cobalt supplied during the production of the positive electrode active material. y2 represents the composition ratio of manganese in the binary transition metal oxide. y2 is greater than 0 and less than 2, preferably greater than 0.1 and less than 1.9, and more preferably greater than 0.5 and less than 1.5. y2 can be controlled by adjusting the amount of manganese supplied when producing the positive electrode active material. ｘ２ Mn ｙ２ O ｚ２ As a binary transition metal oxide consisting of LiNi, from the viewpoint of availability and battery characteristics, ０．５ Mn １．５ O ４ is preferred.

[0146] The LiCo ｘ３ Mn ｙ３ O ｚ３In the binary transition metal oxide comprising the above, x3 represents the composition ratio of cobalt in the binary transition metal oxide. x3 is greater than 0 and less than 2, preferably 0.1 to 1.9, and more preferably 0.5 to 1.5. x3 can be controlled by adjusting the amount of cobalt supplied during the production of the positive electrode active material. y3 represents the composition ratio of manganese in the binary transition metal oxide. y3 is greater than 0 and less than 2, preferably 0.1 to 1.9, and more preferably 0.5 to 1.5. y3 can be controlled by adjusting the amount of manganese supplied during the production of the positive electrode active material.

[0147] The ternary transition metal oxides include LiNi ｘ４ Co ｙ４ Mn ｚ４ O ２ (0<x4<1, 0<y4<1, 0<z4<1, x4+y4+z4=1), and LiNi ｘ５ Co ｙ５ Al ｚ５ O ２ (0<x5<1, 0<y5<1, 0<z5<1, x5+y5+z5=1) In these acidic transition metal oxides, part of the oxygen may be replaced with other non-metal ions such as phosphoric acid, boric acid, or fluorine.

[0148] The LiNi ｘ４ Co ｙ４ Mn ｚ４ O ２In the ternary transition metal oxide comprising the above, x4 represents the composition ratio of nickel in the ternary transition metal oxide. x4 is greater than 0 and less than 1, preferably 0.6 or greater but less than 1, and more preferably 0.6 or greater but less than 0.9. x4 can be controlled by adjusting the amount of nickel supplied during the production of the positive electrode active material. y4 represents the composition ratio of cobalt in the ternary transition metal oxide. y4 is greater than 0 and less than 1, preferably 0.05 or greater but less than 0.2, and more preferably 0.05 or greater but less than 0.1. y4 can be controlled by adjusting the amount of cobalt supplied during the production of the positive electrode active material. z4 represents the composition ratio of manganese in the ternary transition metal oxide. z4 is greater than 0 and less than 1, preferably 0.05 or greater but less than 0.2, and more preferably 0.05 or greater but less than 0.1. The value of z4 can be controlled by adjusting the amount of manganese supplied during the production of the positive electrode active material.

[0149] The LiNi ｘ５ Co ｙ５ Al ｚ５ O ２In the ternary transition metal oxide comprising the above, x5 represents the composition ratio of nickel in the ternary transition metal oxide. x5 is greater than 0 and less than 1, preferably 0.6 or greater but less than 1, and more preferably 0.6 or greater but less than 0.9. x5 can be controlled by adjusting the amount of nickel supplied during the production of the positive electrode active material. y5 represents the composition ratio of cobalt in the ternary transition metal oxide. y5 is greater than 0 and less than 1, preferably 0.05 or greater but less than 0.2, and more preferably 0.05 or greater but less than 0.1. y5 can be controlled by adjusting the amount of cobalt supplied during the production of the positive electrode active material. z5 represents the composition ratio of aluminum in the ternary transition metal oxide. z5 is greater than 0 and less than 1, preferably 0.05 or greater but less than 0.2, and more preferably 0.05 or greater but less than 0.1. z5 can be controlled by adjusting the amount of aluminum supplied during the production of the positive electrode active material.

[0150] Among the positive electrode active materials exemplified above, LiCoO ２ LiNiO ２ ; Li ２ MnO ３ and LiMeO ２ (Me = Mn, Co, Ni) solid solution; LiNi ｘ４ Co ｙ４ Mn ｚ４ O ２ (0<x4<1, 0<y4<1, 0<z4<1, x4+y4+z4=1), or LiNi ｘ５ Co ｙ５ Al ｚ５ O ２ (0<x5<1, 0<y5<1, 0<z5<1, x5+y5+z5=1) is preferred, and LiNi is more preferred. ｘ４ Co ｙ４ Mn ｚ４ O ２ (0.6≦x4<1, 0<y4<0.4, 0<z4<0.4, 0<y4+z4≦0.4, x4+y4+z4=1), or LiNi ｘ５ Co ｙ５Al ｚ５ O ２ A ternary transition metal oxide consisting of (0.6≦x5<1, 0<y5<0.4, 0<z5<0.4, 0<y5+z5≦0.4, x5+y5+z5=1) is used.

[0151] In the case of a sodium ion secondary battery, examples of the material include a transition metal compound having a structure in which sodium ions can diffuse, or an oxide of the transition metal compound and sodium. ２ , NaNiO ２ , NaCoO ２ , NaMnO ２ , NaVO ２ , NaCrO ２ , Na ２ MeSiO ４ (Me=at least one metal element selected from Fe, Mn, and Co), Na ２ MnO ３ + NaMeO ２ (Me=at least one metal element selected from Mn, Co, Ni, and Fe) Solid solution, Na ０．７ (Mn ｘ Ni ｙ Co ｚ ) O ２ (x+y+z=1, 0<x<1, 0<y<1, 0<z<1), Na ２／３ (Ni ｘ Mn ｙ ) O ２ (x+y=1, 0<x<1, 0<y<1), Na ２／３ (Fe ｘ Mn ｙ ) O ２ (x+y=1, 0<x<1, 0<y<1), Na ２／３ (Ni ｘ Mn ｙ Mg ｚ ) O ２ (x+y+z=1, 0<x<1, 0<y<1, 0<z<1), Na ２／３ (Ni ｘ Mn ｙ Al ｚ ) O ２ (x+y+z=1, 0<x<1, 0<y<1, 0<z<1), Na ２ Fe ２ P ２O ７ , Na ３ V ２ (P.O. ４ ) ３ , Na ４ Ni ３ (P.O. ４ ) ２ P ２ O ７ , Na ４ Co ３ (P.O. ４ ) ２ P ２ O ７ , Na ２ Fe ２ (SO ４ ) ３ etc.

[0152] In the case of a potassium ion secondary battery, for example, a transition metal compound having a structure in which potassium ions can diffuse, or an oxide of such a transition metal compound and potassium, can be used. Specifically, KFeO ２ , KNiO ２ , KCoO ２ , KMnO ２ , K. ２／３ MnO ２ , KMnO ４ , K.V.O. ２ , KCrO ２ , KMeSiO ４ (Me=at least one metal element selected from Fe, Mn, and Co.), K ２ MnO ３ +KMeO ２ (Me=at least one metal element selected from Mn, Co, Ni, and Fe.) Solid solution, K(Mn ｘ Ni ｙ Co ｚ ) O ２ (x+y+z=1, 0<x<1, 0<y<1, 0<z<1), K(Ni ｘ Ti ｙ ) O ２ (x+y=1, 0<x<1, 0<y<1), K ２／３ (Ni ｘ Mn ｙ ) O ２ (x+y=1, 0<x<1, 0<y<1), K(Ni ｘ Mn ｙ) O ２ (x+y=1, 0<x<1, 0<y<1), K ２／３ (Fe ｘ Mn ｙ ) O ２ (x+y=1, 0<x<1, 0<y<1), K ３ V ２ (P.O. ４ ) ３ , KMePO ４ (Me=at least one metal element selected from Fe, Mn, and Co.), K ２ MeP.O. ４ F (Me=at least one metal element selected from Fe, Mn, and Co), and the like.

[0153] In the case of a magnesium ion secondary battery, examples of the material include a transition metal compound having a structure in which magnesium ions can diffuse, or an oxide of the transition metal compound and magnesium. ２ , MgCoO ２ , MgMnO ２ , MgMe ２ O ４ (Me=at least one metal element selected from Fe, Mn, Co, Ni, and Cr), MgMeSiO ４ (Me=at least one metal element selected from Fe, Mn, Co, Ni, Cu, and V), Mg (Mn ｘ Ni ｙ Co ｚ ) O ２ (x+y+z=1, 0<x<1, 0<y<1, 0<z<1), MgMePO ４ (Me=at least one metal element selected from Fe, Mn, and Co), MgMePO ４ F (Me=at least one metal element selected from Fe, Mn, Co, and V), MeBO ３ (Me=at least one metal element selected from V, Ti, Mn, and Co.) Mo ６ S ８ , MoS ２ , MnS ２ , TiS ２ , MgMo ６ S ８ , TiNb２ O ７ , V ２ O ５ , MnO ２ , Mn ３ O ４ , KMnO ４ , Mg(MnO ４ ) ２ , FeF ３ , MnF ３ etc.

[0154] In the case of calcium ion secondary batteries, examples of the material include transition metal compounds having a structure that allows calcium ions to diffuse, oxides of such transition metal compounds and calcium, and Prussian blue analogs (PBA). ３ , Ca １／２ CoO ２ , CaV ２ O ５ , MeFe-PBA (Me=at least one metal element selected from Ni, Mn, and Co), and the like.

[0155] The positive electrode 1 can be obtained by pressure molding the positive electrode active material listed above together with a known conductive additive and binder, or by mixing the positive electrode active material together with a known conductive additive and binder in an organic solvent such as pyrrolidone, forming a paste, applying the paste to a current collector such as aluminum foil, and then drying the paste.

[0156] The positive electrode current collector may be any conductive material that is electrochemically and chemically resistant to corrosion. More specifically, a plate or foil of stainless steel, aluminum, titanium, tantalum, or the like can be used. Of these, a plate or foil of stainless steel or aluminum is preferred as the current collector in terms of both performance and cost.

[0157] Examples of the conductive additive include, but are not limited to, graphite, graphene, carbon black, carbon nanotubes, needle coke, etc. These conductive additives may be used alone or in combination.

[0158] The content of the conductive additive in the positive electrode active material layer is preferably 0.01 to 20 mass %, more preferably 0.1 to 15 mass %, and particularly preferably 1 to 10 mass %, from the viewpoint of conductivity.

[0159] The binder is not particularly limited as long as it is a material that is stable to the nonaqueous solvent used in the electrolyte and the solvent used in producing the electrodes, and specific examples include polyethylene, polypropylene, polyethylene terephthalate, cellulose, styrene-butadiene rubber, isoprene rubber, butadiene rubber, fluororubber, acrylonitrile-butadiene rubber, vinyl acetate copolymer, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene, alkali metal ion conductive polymers, etc. Among these, one type or two or more types can be used in appropriate combination.

[0160] The content of the binder contained in the positive electrode active material layer is preferably 0.1 to 30 mass %, more preferably 1 to 20 mass %, and particularly preferably 5 to 10 mass %, from the viewpoints of mechanical strength and conductivity.

[0161] The solvent for forming the slurry is not particularly limited as long as it can dissolve or disperse the positive electrode active material, binder, and conductive additive and can be easily removed by subsequent drying. Examples include water, alcohol, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, tetrahydrofuran, toluene, acetone, dimethyl ether, dimethyl sulfoxide, benzene, xylene, and hexane. These solvents may be used alone or in combination of two or more.

[0162] The material of the negative electrode active material in the negative electrode 2 is not particularly limited, and in the case of a lithium ion secondary battery, examples thereof include materials capable of absorbing and releasing lithium, such as metal composite oxides, lithium metal, lithium alloys, silicon, silicon-based alloys, tin-based alloys, metal oxides, metal sulfides, lithium nitride, conductive polymers such as polyacene, polyacetylene, and polythiophene, and carbon materials.

[0163] The metal composite oxide is not particularly limited, and examples thereof include Li ４ Ti ５ O １２ , Li ｘFe ２ O ３ (0≦x≦1), Li ｘ WO ２ (0≦x≦1), Li ４ WO ５ , Sn ｘ Me １ １－ｘ Me ２ ｙ O ｚ (Me １ = Mn, Fe, Pb, Ge, Me ２ = Al, B, P, Si, elements of groups 1 to 3 of the periodic table, halogens, where 0<x≦1, 1≦y≦3, 1≦z≦8), Sn ２ B ２ O ５ , Sn ２ P ２ O ７ , Sn ２ BPO ６ , TiNb ２ O ７ , Ti ２ Nb １０ O ２９ etc.

[0164] The metal oxide is not particularly limited, and examples thereof include SnO, SnO ２ , SiO ｘ (0<x<2), PbO, PbO ２ , Pb ２ O ３ , Pb ３ O ４ , Sb ２ O ３ , Sb ２ O ４ , Sb ２ O ５ , GeO, GeO ２ , Bi ２ O ３ , Bi ２ O ４ , Bi ２ O ５ , Li ２ O, Al ２ O ３ , ZnO, In ２ O ３ , TiO ２ , Nb ２ O ５ , MoO２ , W.O. ２ , CuO, etc.

[0165] The metal sulfide is not particularly limited, and examples thereof include SnS and FeS. ２ etc.

[0166] The lithium nitride is not particularly limited, and examples thereof include Li ５ (Li ３ N), Li ７ MnN ４ , Li ３ FeN ２ , Li ｘ Co ｙ N (0<x≦3, 0≦y≦1, x+y=3), etc.

[0167] The carbon material is not particularly limited, and examples thereof include carbon black, activated carbon, natural graphite, artificial graphite, boronized graphite, metal-coated graphite, fluorinated graphite, mesocarbon microbeads, graphitized pitch-based carbon fiber, fired organic polymer compounds, carbon nanotubes, hard carbon, fullerene, coke, etc. These may be used alone or in combination of two or more.

[0168] In the case of a sodium ion secondary battery, the material for the negative electrode active material is not particularly limited as long as it is a material that can absorb and release sodium, and examples thereof include sodium metal, metal oxides such as NaTiO, natural graphite, artificial graphite, boronized graphite, hard carbon, a fired organic polymer compound, mesocarbon microbeads, pitch-based carbon fiber graphitized material, carbon nanotubes, and other carbon materials.

[0169] In the case of a potassium ion secondary battery, the material for the negative electrode active material is not particularly limited as long as it is a material that can occlude and release potassium, and examples thereof include carbon materials such as metal composite oxides such as K2Ti6O13, potassium metal, natural graphite, artificial graphite, coke, boronized graphite, hard carbon, carbon black, baked organic polymer compounds, mesocarbon microbeads, pitch-based carbon fiber graphitized material, and carbon nanotubes.

[0170] In the case of a magnesium ion secondary battery, the material for the negative electrode active material is not particularly limited as long as it is a material that can absorb and release magnesium, and examples thereof include carbon materials such as magnesium metal, magnesium alloys, bismuth-added alloys, copper-added alloys, metal composite oxides, natural graphite, artificial graphite, coke, boronized graphite, hard carbon, carbon black, baked organic polymer compounds, mesocarbon microbeads, pitch-based carbon fiber graphitized products, and carbon nanotubes.

[0171] In the case of a calcium ion secondary battery, the material for the negative electrode active material is not particularly limited as long as it is a material that can occlude and release calcium, and examples thereof include carbon materials such as calcium metal, calcium alloys, metal composite oxides, natural graphite, artificial graphite, coke, boronized graphite, hard carbon, carbon black, baked organic polymer compounds, mesocarbon microbeads, pitch-based carbon fiber graphitized material, and carbon nanotubes.

[0172] The electrode material in foil or powder form can be used for the negative electrode 2. In the case of powder form, it can be obtained by pressure molding together with a known conductive additive and binder, or by mixing together with a known conductive additive and binder in an organic solvent such as pyrrolidone to form a paste, which is then applied to a current collector such as copper foil and then dried.

[0173] The negative electrode current collector may be any conductive material that is electrochemically and chemically resistant to corrosion. More specifically, a plate or foil of copper, stainless steel, nickel, etc. can be used. Of these, a copper plate or foil is preferred as the current collector in terms of both performance and cost.

[0174] Examples of the conductive additive include, but are not limited to, graphite, graphene, carbon black, carbon nanotubes, needle coke, etc. These conductive additives may be used alone or in combination.

[0175] The content of the conductive additive in the negative electrode active material layer is preferably 0.01 to 20 mass %, more preferably 0.1 to 15 mass %, and particularly preferably 1 to 10 mass %, from the viewpoint of conductivity.

[0176] The binder is not particularly limited as long as it is a material that is stable to the nonaqueous solvent used in the electrolyte and the solvent used in producing the electrodes, and specific examples include polyethylene, polypropylene, polyethylene terephthalate, carboxymethyl cellulose, styrene-butadiene rubber, isoprene rubber, butadiene rubber, fluororubber, acrylonitrile-butadiene rubber, vinyl acetate copolymer, polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene, alkali metal ion conductive polymers, etc. Among these, one type or two or more types can be used in appropriate combination.

[0177] The content of the binder contained in the negative electrode active material layer is preferably 0.1 to 30 mass %, more preferably 1 to 20 mass %, and particularly preferably 5 to 10 mass %, from the viewpoints of mechanical strength, battery capacity, electrical resistance, etc.

[0178] The solvent for forming the slurry is not particularly limited as long as it can dissolve or disperse the negative electrode active material, binder, and conductive additive and can be easily removed by subsequent drying. Examples of the solvent include water, alcohol, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, tetrahydrofuran, toluene, acetone, dimethyl ether, dimethyl sulfoxide, benzene, xylene, and hexane. These solvents may be used alone or in combination.

[0179] In the lithium-ion secondary battery according to this embodiment, a separator 3 is typically interposed between the positive electrode 1 and the negative electrode 2 to prevent short-circuiting between them. The material and shape of the separator 3 are not particularly limited, but a material that is easily permeable to the nonaqueous electrolyte, insulating, and chemically stable is preferred. Examples include microporous films, sheets, and nonwoven fabrics made of various polymeric materials, those with glass coatings on their surfaces, and glass fiber nonwoven fabrics. Specific examples of polymeric materials include polyolefin-based polymers such as nylon (registered trademark), nitrocellulose, polyacrylonitrile, polyimide, polyvinylidene fluoride, polyethylene, and polypropylene. From the viewpoints of electrochemical and chemical stability, polyolefin-based polymers are preferred.

[0180] The lithium ion secondary battery of this embodiment can be charged at a high charging voltage, preferably 4.3 V or higher, more preferably in the range of 4.3 V to 5 V, even more preferably in the range of 4.35 V to 4.8 V, and particularly preferably in the range of 4.4 V to 4.7 V.

[0181] The shape of the lithium ion secondary battery of this embodiment is not particularly limited, and examples thereof include a cylindrical type, a square type, a laminate type, and the like in addition to the coin type cell shown in FIG.

[0182] The secondary battery according to this embodiment can exhibit excellent cycle characteristics even in a high-temperature environment, and the nonaqueous electrolyte solution according to this embodiment can be suitably used for, for example, a lithium-ion secondary battery. However, the lithium-ion secondary battery shown in FIG. 1 is an example of one embodiment of the secondary battery of the present invention, and the secondary battery of the present invention is not limited thereto.

[0183] Preferred examples of the present invention are described in detail below. However, the materials and blending amounts described in the examples are not intended to limit the scope of the present invention unless otherwise specified.

[0184] Example 1 Preparation of Non-Aqueous Electrolyte Solution In an argon glove box with a dew point of −70° C. or less, a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio of EC:DMC=1:1, manufactured by Kishida Chemical Co., Ltd., lithium battery grade) was dissolved in LiPF ６ The following were mixed: LiPF ６ The mixture of LiPF ６ The concentration was adjusted to 1.0 mol / liter.

[0185] Next, lithium phenoxide (LiOPh) and vinylene carbonate (VC) were added as additives to the nonaqueous electrolyte solution so that the respective additive concentrations were 0.2 mass % relative to the total mass of the nonaqueous electrolyte solution, thereby preparing the nonaqueous electrolyte solution of this example.

[0186] Example 2 In this example, a nonaqueous electrolyte solution of this example was prepared in the same manner as in Example 1, except that lithium difluorophosphate (LiDFP) was added to a concentration of 0.2 mass % instead of the vinylene carbonate of Example 1.

[0187] Example 3 In this example, a non-aqueous electrolyte solution of this example was prepared in the same manner as in Example 1, except that fluoroethylene carbonate (FEC) was added in a concentration of 0.2 mass % instead of vinylene carbonate in Example 1.

[0188] Example 4 In this example, a non-aqueous electrolyte solution of this example was prepared in the same manner as in Example 2, except that sodium phenoxide was added to a concentration of 0.2 mass % instead of the lithium phenoxide of Example 2.

[0189] Example 5 In this example, a nonaqueous electrolyte solution of this example was prepared in the same manner as in Example 2, except that lithium 4-tert-amylphenoxide was added to a concentration of 0.2 mass % instead of the lithium phenoxide of Example 2.

[0190] Comparative Example 1 In an argon glove box with a dew point of −70° C. or less, a mixed solvent of ethylene carbonate (EC) and dimethyl carbonate (DMC) (volume ratio of EC:DMC=1:1, manufactured by Kishida Chemical Co., Ltd., lithium battery grade) was used to ６ The following were mixed: LiPF ６ The mixture of LiPF ６ The concentration of the non-aqueous electrolyte solution of this comparative example was adjusted to 1.0 mol / L.

[0191] Comparative Example 2 In this comparative example, a non-aqueous electrolyte solution of this comparative example was prepared in the same manner as in Example 1, except that the vinylene carbonate of Example 1 was not added.

[0192] Comparative Example 3 In this comparative example, a non-aqueous electrolyte solution of this comparative example was prepared in the same manner as in Example 1, except that the lithium phenoxide of Example 1 was not added.

[0193] Comparative Example 4 In this comparative example, a non-aqueous electrolyte solution of this comparative example was prepared in the same manner as in Example 2, except that the lithium phenoxide of Example 2 was not added.

[0194] Comparative Example 5 In this comparative example, a non-aqueous electrolyte solution of this comparative example was prepared in the same manner as in Example 3, except that the lithium phenoxide of Example 3 was not added.

[0195] Comparative Example 6 In this comparative example, a non-aqueous electrolyte solution of this comparative example was prepared in the same manner as in Example 4, except that lithium difluorophosphate was not added.

[0196] (Evaluation of High-Temperature Storage Characteristics and Cycle Characteristics) <Preparation of Coin Cells> Coin-type lithium secondary batteries (coin cells) as shown in FIG. 1 were prepared using the nonaqueous electrolyte solutions prepared in Examples 1 to 5 and Comparative Examples 1 to 6, respectively, and their electrochemical characteristics were evaluated.

[0197] That is, the positive electrode was made of LiNi cut into a diameter of 15 mm. ０．６ Co ０．２ Mn ０．２ O ２A cathode (manufactured by Piotrec Corporation) was used, and glass filter paper (product name: GC-50, manufactured by Advantec Toyo Kaisha, Ltd.) was used as the separator. Furthermore, natural graphite (manufactured by Piotrec Corporation) cut to a diameter of 16 mm was used for the negative electrode. The positive electrode, separator, and negative electrode were stacked in this order to form a laminate, which was then impregnated with the nonaqueous electrolyte prepared in Examples 1 to 5 and Comparative Examples 1 to 6. The laminate was then sealed to produce each coin cell. The coin cells were all assembled in an argon glove box with a dew point of -70°C or lower.

[0198] <Break-in of coin cells> Each of the produced coin cells was charged to an end voltage of 4.4 V at a charging current of 0.2 C (the current value at which the rated capacity is charged or discharged in 1 hour is defined as 1 C) in a thermostatic chamber at 25°C, and then the coin cells were held at a constant potential of 4.4 V until the charging current fell to 0.05 C or less. They were then discharged to an end voltage of 3.0 V at a discharging current of 0.2 C. Under these charge / discharge conditions, three cycles of charge / discharge were performed using a constant current / constant voltage method, and the discharge capacity at the third cycle was defined as the initial discharge capacity.

[0199] <High-Temperature Storage Test> Next, after the break-in, each coin cell was charged in a thermostatic chamber at 25° C. with a charging current of 0.2 C up to a cut-off voltage of 4.4 V, and the charging was terminated by holding the potential at 4.4 V until the charging current became equal to or less than 0.05 C. Thereafter, the temperature in the thermostatic chamber was changed to 60° C., and each charged coin cell was stored at high temperature for 2 weeks.

[0200] After two weeks, the temperature in the thermostatic chamber was returned to 25°C, and each coin cell after the high-temperature storage test was discharged at a discharge current of 0.2 C to a final voltage of 3.0 V. The capacity at this time was recorded as the discharge capacity after high-temperature storage. Table 1 shows the ratio of the discharge capacity after storage to the initial discharge capacity of 100.

[0201] <Measurement of Internal Resistance of Coin Cells> The internal resistance of each coin cell was determined by an AC impedance method. Each coin cell after high-temperature storage was charged at a constant temperature of 25°C with a charging current of 0.2 C to a final voltage of 4.4 V, and a sine wave with an amplitude of ±10 mV and a frequency of 1 MHz to 50 mHz was superimposed. The internal resistance of each coin cell was determined from the resulting Nyquist plot. Table 2 shows the ratio of the internal resistance of each coin cell to the internal resistance of the coin cell using the nonaqueous electrolyte of Comparative Example 1, which is set to 100.

[0202] <Cycle characteristic test> After high-temperature storage, each coin cell was charged in a thermostatic chamber at 25°C at a charging current of 1.0 C to an end voltage of 4.4 V, and then held at a constant potential of 4.4 V until the charging current fell to 0.05 C or less. It was then discharged at a discharge current of 0.2 C to an end voltage of 3.0 V. Under these charge / discharge conditions, 100 charge / discharge cycles were performed using a constant current / constant voltage method. The discharge capacities at the 100th cycle were compared and evaluated. Table 3 shows the ratios of the discharge capacities of Examples 1 to 5 and Comparative Examples 2 to 6, with Comparative Example 1 set to 100.

[0203]

[0204]

[0205]

[0206] As is clear from Tables 1 to 3, the coin cells using the nonaqueous electrolyte solutions of Examples 1 to 5 had higher discharge capacities after being charged at a high charging voltage of 4.4 V and further stored at a high temperature of 60° C. for two weeks, compared to Comparative Examples 1 to 6. The coin cells also had lower internal resistance and were superior in cycle characteristics. Industrial Applicability

[0207] The nonaqueous electrolyte according to this embodiment can be suitably used in, for example, lithium ion secondary batteries.

[0208] 1 Positive electrode 2 Negative electrode 3 Separator 4 Positive electrode can 5 Negative electrode can 6 Gasket 7 Spacer 8 Spring

Claims

1. A non-aqueous electrolyte for a secondary battery, comprising at least one of the following components (A) and at least one of the following components (B) as additives: Component (A): a compound represented by the following chemical formula (1): (However, the above M ｎ＋ represents any one selected from the group consisting of an alkali metal ion, an alkaline earth metal ion, an aluminum ion, a transition metal ion, and an onium ion. １ ~α ５ each independently represents a hydrogen atom, a halogen atom, a hydroxy group, a mercapto group, a nitro group, a formyl group, a sulfo group, a carboxy group, an acetyl group, a sulfonamido group, a cyano group, an amino group, a thio group containing a hydrocarbon group having 1 to 20 carbon atoms, an amino group containing a hydrocarbon group having 1 to 20 carbon atoms, a sulfonyl group containing a hydrocarbon group having 1 to 20 carbon atoms, a hydrocarbon group or alkoxy group having 1 to 20 carbon atoms, or a hydrocarbon group or alkoxy group having a carbon number in the range of 1 to 20 and having at least one of a halogen atom, a hetero atom, or an unsaturated bond. １ ~α ５ are either hydrocarbon groups or alkoxy groups having 1 to 20 carbon atoms, or hydrocarbon groups or alkoxy groups having 1 to 20 carbon atoms and at least one of a halogen atom, a hetero atom, or an unsaturated bond, which are mutually bonded to form a cyclic structure. The n represents a valence. Component (B): a boron complex salt represented by the following chemical formula (2), or at least one compound selected from the group consisting of boric acid esters, acid anhydrides, cyclic carbonates having unsaturated bonds, cyclic carbonates having halogen atoms, cyclic sulfonate esters, cyclic sulfate esters, cyclic sulfite esters, amines having an acetoacetyl group represented by the following chemical formula (3), phosphorus compounds represented by any of the following chemical formulas (4) to (6), sulfonylimide salts and sulfonate salts, and dinitriles. (The above M ｎ＋ represents a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an aluminum ion, a transition metal ion, or an onium ion. １ ~X ４ are each independent, and one or two arbitrarily selected combinations form a cyclic structure of -OOC-COO-, -OOCO-, -OOC-Y-COO-, -O-Y-O-, or -OOC-Y-O-, in which case each Y independently represents a hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and having a heteroatom, an unsaturated bond, or a cyclic structure. Alternatively, １ ~X ４ each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond, or an alkoxy group having 1 to 20 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond. The n represents a valence. (The above R ２ and R ３ each independently represents a hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and having a halogen atom, a hetero atom, or an unsaturated bond. (In the formula, the M ｎ＋ represents a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an aluminum ion, a transition metal ion, or an onium ion. １ and A ２ Each of X independently represents an oxygen atom, a sulfur atom, or a selenium atom. ５ and X ６ each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms and at least one of a halogen atom, a heteroatom, or an unsaturated bond. ５ and X ６ is either an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms and at least one of a halogen atom, a hetero atom, or an unsaturated bond, which are bonded to each other to form a cyclic structure. The n represents a valence. (In the formula, the M ｎ＋ represents a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an aluminum ion, a transition metal ion, or an onium ion. ７ ~X １２ each independently represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkylthio group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms and having at least one of a halogen atom, a heteroatom, or an unsaturated bond, an alkylthio group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms and having at least one of a halogen atom, a heteroatom, or an unsaturated bond, an alkylthio group having 1 to 20 carbon atoms, or an alkylthio group having 1 to 20 carbon atoms and having at least one of a halogen atom, a heteroatom, or an unsaturated bond. ７ ~X １２ at least one arbitrarily selected combination forms a cyclic structure of -OOC-COO-, -OOCO-, -OOC-Z-COO-, -OOC-Z-O- or -O-Z-O-, in which case Z represents a hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and at least one of a halogen atom, a hetero atom, an unsaturated bond or a cyclic structure. The n represents a valence. (The M ｎ＋ represents a hydrogen ion, an alkali metal ion, an alkaline earth metal ion, an aluminum ion, a transition metal ion, or an onium ion. ４ and R ５ each independently represents a hydrocarbon group having 1 to 20 carbon atoms, or a hydrocarbon group having 1 to 20 carbon atoms and at least one of a halogen atom, a hetero atom, or an unsaturated bond. ４ and R ５ represents either the hydrocarbon group having 1 to 20 carbon atoms, or the hydrocarbon group having 1 to 20 carbon atoms and at least one of a halogen atom, a hetero atom, or an unsaturated bond, which are bonded to each other to form a cyclic structure. The n represents a valence.

2. The non-aqueous electrolyte for a secondary battery according to claim 1, wherein the content of said component (A) is 0.05 to 5 mass % based on the total mass of said non-aqueous electrolyte for a secondary battery.

3. The non-aqueous electrolyte for a secondary battery according to claim 1, wherein the content of said component (B) is 0.05 to 5 mass % based on the total mass of said non-aqueous electrolyte for a secondary battery.

4. The nonaqueous electrolyte for a secondary battery according to claim 1, wherein the component (A) is lithium phenoxide, lithium 4-tert-amylphenoxide or sodium phenoxide.

5. The nonaqueous electrolyte for a secondary battery according to claim 1, wherein the component (B) is 1,3-propane sultone.

6. The nonaqueous electrolyte for a secondary battery according to claim 1, wherein the component (B) is vinylene carbonate.

7. The nonaqueous electrolyte for a secondary battery according to claim 1, wherein said component (B) is fluoroethylene carbonate.

8. The nonaqueous electrolyte for a secondary battery according to claim 1, wherein the component (B) is lithium difluorophosphate.

9. The nonaqueous electrolyte for a secondary battery according to claim 1, wherein the component (B) is lithium difluorooxalatoborate.

10. The nonaqueous electrolyte for a secondary battery according to claim 1, wherein the component (B) is lithium difluorobisoxalatophosphate.

11. The nonaqueous electrolyte for a secondary battery according to claim 1, wherein said component (B) is lithium tetrafluorooxalatophosphate.

12. The nonaqueous electrolyte for a secondary battery according to claim 1, wherein the component (B) is lithium bis(fluorosulfonyl)imide.

13. The nonaqueous electrolyte for a secondary battery according to claim 1, wherein the component (B) is lithium fluorosulfonate.

14. The nonaqueous electrolyte for a secondary battery according to claim 1, wherein the component (B) is succinonitrile.

15. A secondary battery comprising at least the nonaqueous electrolyte for secondary batteries according to any one of claims 1 to 14, a positive electrode and a negative electrode.

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