JP2008004349A - Nonaqueous electrolyte, and secondary battery using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqeous electrolyte capable of maintaining small internal resistance and high electric capacity when using it for a long period of time and preserving it in high temperatures, and a nonaquous electrolyte secondary battery containing the nonaqueous electrolyte. <P>SOLUTION: A cyclic carbonate compound containing an unsaturated group is added to an electrolyte obtained by dissolving an organic solvent in electrolyte salt. Thereby, the nonaqueous electrolyte acting on a coat formed on the surface of an electrode to enhance durability and thermal resistance and the nonaqueous secondary battery containing the nonaqueous electrolyte are obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a non-aqueous electrolyte solution containing an unsaturated bond-containing compound having a specific structure and a cyclic carbonate compound, and a non-aqueous electrolyte secondary battery using the electrolyte solution.

  With the spread of portable electronic devices such as portable personal computers and handy video cameras in recent years, non-aqueous electrolyte secondary batteries having high voltage and high energy density have been widely used as power sources. Also, from the viewpoint of environmental problems, battery cars and hybrid cars using electric power as a part of power have been put into practical use.

However, the non-aqueous electrolyte secondary battery exhibits a decrease in electric capacity and an increase in internal resistance when it is stored at a high temperature or repeatedly charged and discharged, and is not reliable as a stable power supply source.
Various additives have been proposed in order to improve the stability and electrical characteristics of the nonaqueous electrolyte secondary battery. For example, JP-A-5-74486 discloses vinylene carbonate, which is a cyclic compound, for forming a stable coating so-called SEI (Solid Electrolyte Interface) on a lithium negative electrode. An electrolytic solution containing it has been proposed, and JP-A-4-87156 proposes an electrolytic solution containing vinylethylene carbonate. JP-A-8-45545 and JP-A-2001-6729 propose an electrolytic solution containing vinylene carbonate, vinylethylene carbonate or the like in order to form a stable film on a graphite-based negative electrode having high crystallinity. Yes.

  Electrolytes containing cyclic compounds containing unsaturated groups such as vinylene carbonate and vinyl ethylene carbonate are suitable for any negative electrode such as lithium, natural graphite, artificial graphite, graphitizable carbon, non-graphitizable carbon, carbon-coated natural graphite, and polyacene. Even when used, a certain effect can be obtained. This is because by covering the surface of the negative electrode with a film, suppression of side reactions such as decomposition of the solvent that has occurred on the negative electrode surface is alleviated, and an initial reduction in irreversible capacity is improved. Therefore, especially vinylene carbonate is widely used as an electrolyte solution additive. However, the effect was not sufficient. That is, the film formed of vinylene carbonate, vinyl ethylene carbonate, etc. has low durability, so it decomposes during long-term use of the battery or in an environment of 80 ° C. or higher, and the negative electrode surface is exposed again after the film is decomposed. Therefore, there is a weak point that the battery deteriorates during long-term use of the battery or in an environment of 80 ° C. or higher. If it is added excessively in the electrolyte solution to compensate for this weak point, the initial increase in resistance increases due to the resistance of the generated film components, and conversely causes a problem in that the battery performance decreases. For this reason, the addition of cyclic compounds such as vinylene carbonate and vinyl ethylene carbonate to the electrolytic solution has not led to fundamental resolution of the long-term characteristics and high-temperature characteristics of the battery.

  In JP-A-2002-134169 and JP-A-2004-39510, a silicon compound is added to an electrolyte solution, so that the rate of change in internal resistance is small and the increase in internal resistance at low temperatures is small. Batteries that can maintain electric capacity have been proposed. However, the effect was not yet satisfactory.

Japanese Patent Laid-Open No. 05-74486 Japanese Unexamined Patent Publication No. 04-87156 Japanese Patent Application Laid-Open No. 08-045545 JP 2001-006729 A JP 2002-134169 A JP 2004-039510 A

  Accordingly, an object of the present invention is to provide a non-aqueous electrolyte capable of providing a battery capable of maintaining a small internal resistance and a high electric capacity during long-term use or high-temperature storage, and a non-aqueous electrolyte using the non-aqueous electrolyte. The next battery is to provide.

  As a result of intensive studies, the present inventors achieved the above object by including an unsaturated bond-containing compound having a specific structure and a cyclic carbonate compound in an electrolytic solution in which an electrolyte salt is dissolved in an organic solvent. I found out that

  That is, the present invention has been made based on the above knowledge, and in an electrolytic solution in which an electrolyte salt is dissolved in an organic solvent, it contains both component (A) and component (B). It contains at least one selected from the unsaturated bond-containing compounds represented by any one of (1), (2), (3) and (4), and the component (b) is unsaturated The object is achieved by providing a non-aqueous electrolyte characterized by being a cyclic carbonate compound containing a group and a non-aqueous electrolyte secondary battery containing the non-aqueous electrolyte as the electrolyte.

（式中、Ｍは、Ｓｉ、ＧｅまたはＳｎ原子を示し、Ａは、直接結合または炭素原子数１〜８のアルキレン基を示し、Ｒ₁およびＲ₂は、それぞれ独立に、ハロゲン原子で置換してもよい炭素原子数１〜８のアルキル基、炭素原子数２〜８のアルケニル基またはハロゲン原子で置換してもよい炭素原子数６〜１８のアリール基を示し、Ｒ₃は、炭素原子数１〜８のアルキレン基または−ＣＯ−Ｂ−ＣＯ−を示し、Ｂは、直接結合または炭素原子数１〜８のアルキレン基を示す。Ｒ₄は、炭素原子数１〜８のアルキレン基、炭素原子数２〜８のアルケニレン基またはハロゲン原子で置換されてもよい炭素原子数６〜８のアリーレン基を示す。）

Wherein M represents a Si, Ge or Sn atom, A represents a direct bond or an alkylene group having 1 to 8 carbon atoms, and R ₁ and R ₂ are each independently substituted with a halogen atom. An optionally substituted alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an aryl group having 6 to 18 carbon atoms which may be substituted with a halogen atom, and R ₃ represents the number of carbon atoms 1 represents an alkylene group having 1 to 8 or —CO—B—CO—, B represents a direct bond or an alkylene group having 1 to 8 carbon atoms, R ₄ represents an alkylene group having 1 to 8 carbon atoms, carbon An alylene group having 2 to 8 atoms or an arylene group having 6 to 8 carbon atoms which may be substituted with a halogen atom.

  In the present invention, the surface state of the electrode can be brought into an ideal state by adding the unsaturated bond-containing compound and the cyclic carbonate to the electrolytic solution. That is, in the present invention, the unsaturated bond-containing compound acts on a film (SEI) formed on the electrode surface to improve its durability and heat resistance. This film contributes to the Li conductivity of the electrode surface, and by stabilizing it, the battery has excellent durability that could never be obtained by conventional electrolytes, that is, in long-term use and high-temperature storage. The battery can maintain a small internal resistance and a high electric capacity for a long time.

  The nonaqueous electrolyte solution of the present invention and the nonaqueous electrolyte secondary battery using the nonaqueous electrolyte solution will be described in detail below.

In the nonaqueous electrolytic solution of the present invention, in the general formula (1), M represents a Si, Ge, or Sn atom. In the general formulas (1), (2), (3) and (4), the alkylene group having 1 to 8 carbon atoms represented by A is methylene, ethylene, trimethylene, methylethylene, tetramethylene, pentamethylene. , Hexamethylene, heptamethylene, octamethylene and the like. Examples of the alkyl group having 1 to 8 carbon atoms that may be substituted with the halogen atom represented by R ₁ and R ₂ in the general formula (1) include methyl, ethyl, propyl, butyl, sec-butyl, tert-butyl, Examples include pentyl, hexyl, heptyl, octyl, 2-ethyl-hexyl, trifluoromethyl, tetrafluoroethyl, heptafluoropropyl, 2,2,2-trifluoroethyl, etc., and examples of the alkenyl group having 2 to 8 carbon atoms Are vinyl, allyl, 1-propenyl, isopropenyl, 2-butenyl, 1,3-butadienyl, 2-pentenyl, 2-octenyl, etc., and having 6 to 18 carbon atoms which may be substituted with a halogen atom As the aryl group, phenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2,4-difluoro Phenyl, 3,5-difluorophenyl,
2,6-difluorophenyl, 2,3-difluorophenyl, 4,5-difluorophenyl, 2,4,6-trifluorophenyl, tetrafluorophenyl and the like can be mentioned. Examples of the alkylene group having 1 to 8 carbon atoms represented by R ₃ and B in the general formula (2) include methylene, ethylene, trimethylene, methylethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene and the like. In general formula (4), examples of the alkyl group having 1 to 8 carbon atoms represented by R ₄ include methyl, ethyl, propyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl 2-ethylhexyl and the like, and examples of the alkenylene group having 2 to 8 carbon atoms include vinylene, propynylene, butenylene, pentenylene and the like, and an arylene group having 6 to 8 carbon atoms which may be substituted with a halogen atom. As phenylene, fluorophenylene, difluorophenylene, etc. .

  As the unsaturated bond-containing compound of the component (a) represented by the general formula (1), (2), (3) or (4), the following compound No. 1-Compound No. 1 14 and the like, but are not limited to these compounds.

  Examples of the cyclic carbonate compound containing an unsaturated group of the component (b) include vinylene carbonate (VC), vinyl ethylene carbonate (VEC), propylidene carbonate, ethylene ethylidene carbonate, ethylene isopropylidene carbonate, and vinylene. Carbonate or vinyl ethylene carbonate is preferred.

In the silicon compound represented by the general formula (5), (6), (7), (8) or (9), carbon which may be substituted with a halogen atom represented by R ₅ , R ₆ and R ₇ Examples of the alkyl group having 1 to 8 atoms include methyl, ethyl, propyl, butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethyl-hexyl, trifluoromethyl, tetrafluoroethyl, hepta Fluoropropyl, 2,2,2-trifluoroethyl and the like. Examples of the alkenyl group having 2 to 8 carbon atoms include vinyl, allyl, 1-propenyl, isopropenyl, 2-butenyl, 1,3-butadienyl, 2-pentenyl, 2-octenyl and the like are mentioned, and examples of the aryl group having 6 to 18 carbon atoms which may be substituted with an alkyl group or a halogen atom include phenyl 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2,4-difluorophenyl, 3,5-difluorophenyl, 2,6-difluorophenyl, 2,3-difluorophenyl, 4,5-difluorophenyl 2,4,6-trifluorophenyl, 2,3,4-trifluorophenyl, tetrafluorophenyl, p-tolyl, m-tolyl, o-tolyl, 2,4-xylyl, 3,5-xylyl, etc. Can be mentioned. Examples of the alkylene group having 1 to 8 carbon atoms represented by R _8, methylene, ethylene, trimethylene, methylethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene and the like, the table in R ₉ Examples of the alkenyl group having 2 to 8 carbon atoms include vinyl, allyl, 1-propenyl, isopropenyl, 2-butenyl, 1,3-butadienyl, 2-pentenyl, 2-octenyl and the like.

  When m is 1, the alkoxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom represented by X includes methoxy, ethoxy, propoxy, butoxy, second butoxy, tertiary butoxy, pentoxy, hexyloxy, Examples include heptoxy, octyloxy, 2-ethyl-hexyloxy, 2,2,2-trifluoroethoxy, etc., and examples of the alkenyloxy group having 2 to 8 carbon atoms include vinyloxy, allyloxy, 1-propoxy, isopropoxy and the like. The aryloxy group having 6 to 8 carbon atoms that may be substituted with a halogen atom includes phenoxy, p-fluorophenoxy, m-fluorophenoxy, o-fluorophenoxy, 2,4-difluorophenoxy, 3,5- Difluorophenoxy, p-methylphenoxy, m-methylphenoxy, o- Examples thereof include methylphenoxy, 2,4-dimethylphenoxy, 3,5-dimethylphenoxy, etc. Examples of the acyloxy group having 2 to 8 carbon atoms that may be substituted with a halogen atom include acetoxy, propionyloxy, trifluoroacetoxy Examples of the sulfonate group having 1 to 8 carbon atoms that may be substituted with a halogen atom include methanesulfonate, ethanesulfonate, propanesulfonate, butanesulfonate, pentanesulfonate, hexanesulfonate, heptanesulfonate, and octane. Sulfonate, trifluoromethane sulfonate, pentafluoroethane sulfonate, hexafluoropropane sulfonate, perfluorobutane sulfonate, perfluoropentane sulfonate, perfluorohexane Sulfonates, perfluoro heptane sulfonate, perfluoro octane sulfonate, and the like.

  When m is 2, the alkylene group having 1 to 8 carbon atoms which may be substituted with a halogen atom represented by X includes methylene, ethylene, methylmethylene, trimethylene, methylethylene, tetramethylene, pentamethylene, hexamethylene , Heptamethylene, octamethylene, difluoromethylene, tetrafluoroethylene, hexafluorotrimethylene and the like. Examples of the alkylenedioxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom include alkylenedioxy groups derived from the above alkylene groups having 1 to 8 carbon atoms. Examples of the alkenylene group having 2 to 8 carbon atoms include vinylene, propynylene, butenylene and pentenylene. Examples of the alkenylene dioxy group having 2 to 8 carbon atoms include alkenylene dioxy groups derived from the above alkenylene group having 2 to 8 carbon atoms. Examples of the alkynylene group having 2 to 8 carbon atoms include ethynylene, propynylene, butynylene and pentynylene. Examples of the alkynylene dioxy group having 2 to 8 carbon atoms include alkynylene dioxy groups derived from the alkynylene group having 2 to 8 carbon atoms. Examples of the arylene group having 6 to 8 carbon atoms which may be substituted with a halogen atom include phenylene, fluorophenylene, difluorophenylene and the like. The aryleneoxy group having 6 to 8 carbon atoms which may be substituted with a halogen atom includes an aryleneoxy group derived from the above arylene group. Examples of the diacyloxy group having 2 to 8 carbon atoms include oxalyloxy, malonyloxy, succinyloxy, maleyloxy, fumaryloxy and the like.

  Examples of the alkoxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom represented by Y include methoxy, ethoxy, propoxy, butoxy, sec-butoxy, tert-butoxy, pentoxy, hexyloxy, heptoxy, octyloxy, 2- Examples include ethyl-hexyloxy, 2,2,2-trifluoroethoxy, etc., and examples of the alkenyloxy group having 2 to 8 carbon atoms include vinyloxy, allyloxy, 1-properoxy, isoproperoxy and the like, which are substituted with a halogen atom. Examples of the aryl group having 6 to 18 carbon atoms include phenyl, 2-fluorophenyl, 3-fluorophenyl, 4-fluorophenyl, 2,4-difluorophenyl, 3,5-difluorophenyl, 2,6- Difluorophenyl, 2,3-difluorophenyl, 4,5-difluoroph Sulfonyl, 2,4,6-trifluorophenyl, tetrafluorophenyl, and the like. Examples of the aryloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom include phenoxy, p-fluorophenoxy, m-fluorophenoxy, o-fluorophenoxy, 2,4-difluorophenoxy and 3,5-difluoro. Examples thereof include phenoxy, p-methylphenoxy, m-methylphenoxy, o-methylphenoxy, 2,4-dimethylphenoxy, 3,5-dimethylphenoxy, etc., and those having 2 to 8 carbon atoms that may be substituted with a halogen atom Examples of the acyloxy group include acetoxy, propionyloxy, trifluoroacetoxy, difluoroacetoxy, and the like. Examples of the sulfonate group having 1 to 8 carbon atoms that may be substituted with a halogen atom include methanesulfonate, ethanesulfonate, and propanesulfonate. , Butanesulfonate, pentanesulfonate Hexane sulfonate, heptane sulfonate, octane sulfonate, trifluoromethane sulfonate, pentafluoroethane sulfonate, hexafluoropropane sulfonate, perfluorobutane sulfonate, perfluoropentane sulfonate, perfluorohexane sulfonate, perfluoroheptane sulfonate, perfluorooctane sulfonate Etc.

  Examples of the alkylene group having 1 to 8 carbon atoms which may be substituted with a halogen atom represented by Z include methylene, ethylene, methylmethylene, trimethylene, methylethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene , Difluoromethylene, tetrafluoroethylene, hexafluorotrimethylene and the like. Examples of the alkylenedioxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom include alkylenedioxy groups derived from the above alkylene groups having 1 to 8 carbon atoms. Examples of the alkenylene group having 2 to 8 carbon atoms include vinylene, propynylene, butenylene and pentenylene. Examples of the alkenylene dioxy group having 2 to 8 carbon atoms include alkenylene oxy groups derived from the above alkenylene group having 2 to 8 carbon atoms. Examples of the alkynylene group having 2 to 8 carbon atoms include ethynylene, propynylene, butynylene and pentynylene. Examples of the alkynylene dioxy group having 2 to 8 carbon atoms include alkynylene dioxy groups derived from the alkynylene group having 2 to 8 carbon atoms. Examples of the arylene group having 6 to 8 carbon atoms which may be substituted with a halogen atom include phenylene, fluorophenylene, difluorophenylene and the like. The aryleneoxy group having 6 to 8 carbon atoms which may be substituted with a halogen atom includes an aryleneoxy group derived from the above arylene group. Examples of the diacyloxy group having 2 to 8 carbon atoms include oxalyloxy, malonyloxy, succinyloxy, maleyloxy, fumaryloxy and the like.

  As the compound represented by the general formula (5), (6), (7), (8) or (9), the following compound No. 19 to Compound No. 99 and the like, but are not limited thereto.

The weight ratio of the component (I) and the component (B) in the non-aqueous electrolyte of the present invention is 50: 100 to 1: 100, preferably 20: 100 to 2: 100, more preferably 15: 100 to 4: 100. Ingredient (a) is less than 1: 100 of the ingredient (b), and its effect is hardly recognized. Even if it is contained in excess of 50: 100, the effect is not manifested any more, so it is not only useless. On the other hand, it may adversely affect the characteristics of the electrolyte, which is not preferable.
The total content of component (a) and component (b) in the non-aqueous electrolyte is 0.05 to 20% by mass, preferably 0.05 to 10% by mass, more preferably 0.1. ˜5 mass%. If it is less than 0.05% by mass, it is difficult to recognize the effect, and even if it is contained in excess of 20% by mass, the effect is not manifested any more, so it is not only useless, but adversely affects the properties of the electrolyte. Since it may affect, it is not preferable. The content of the silicon compound represented by the general formula (5), (6), (7), (8) or (9) is 0.05 to 20% by mass, preferably 0.05 to 10%. It is mass%, More preferably, it is 0.1-5 mass%. If it is less than 0.05% by mass, it is difficult to recognize the effect, and even if it is contained in excess of 20% by mass, the effect will not be manifested any more, so it is not only useless, but adversely affects the properties of the electrolyte. Since it may affect, it is not preferable. A silicon compound can be used 1 type or in combination of 2 or more types.

  The organic solvents used in the nonaqueous electrolytic solution of the present invention are listed more specifically below. However, the organic solvent used in the present invention is not limited by the following examples.

  Since the cyclic carbonate compound, the cyclic ester compound, the sulfone or sulfoxide compound, and the amide compound have a high relative dielectric constant, they serve to increase the dielectric constant of the electrolytic solution. Specifically, examples of the cyclic carbonate compound include ethylene carbonate (EC), propylene carbonate (PC), 1,2-butylene carbonate, and isobutylene carbonate. Examples of the cyclic ester compound include γ-butyrolactone and γ-valerolactone. Examples of the sulfone or sulfoxide compound include sulfolane, sulfolene, tetramethylsulfolane, diphenyl sulfone, dimethyl sulfone, dimethyl sulfoxide, propane sultone, butylene sultone, and among these, sulfolanes are preferable. Examples of the amide compound include N-methylpyrrolidone, dimethylformamide, dimethylacetamide and the like.

  The chain carbonate compound, the chain or cyclic ether compound, and the chain ester compound can lower the viscosity of the non-aqueous electrolyte. Therefore, battery characteristics such as power density can be improved, such as the mobility of electrolyte ions can be increased. Moreover, since it is low-viscosity, the performance of the non-aqueous electrolyte at low temperatures can be increased. Specifically, as the chain carbonate compound, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), ethyl-n-butyl carbonate, methyl-t-butyl carbonate, di-i- Examples thereof include propyl carbonate and t-butyl-i-propyl carbonate. Examples of the chain or cyclic ether compound include dimethoxyethane (DME), ethoxymethoxyethane, diethoxyethane, tetrahydrofuran, dioxolane, dioxane, 1,2-bis (methoxycarbonyloxy) ethane, 1,2-bis (ethoxycarbonyl). Oxy) ethane, 1,2-bis (ethoxycarbonyloxy) propane, ethylene glycol bis (trifluoroethyl) ether, i-propylene glycol (trifluoroethyl) ether, ethylene glycol bis (trifluoromethyl) ether, diethylene glycol bis ( Trifluoroethyl) ether and the like, and among them, dioxolanes are preferable. Examples of the chain ester compound include carboxylic acid ester compounds represented by the following general formula (10).

（式中、Ｒは炭素原子数１〜４のアルキル基を示し、ｎは０、１又は２を示す。）

(In the formula, R represents an alkyl group having 1 to 4 carbon atoms, and n represents 0, 1 or 2.)

  In the general formula (10), examples of the alkyl group having 1 to 4 carbon atoms represented by R include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl and tert-butyl. Specific examples of the carboxylic acid ester compound represented by 10) include methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, sec-butyl acetate, butyl acetate, methyl propionate, and ethyl propionate. It is done. The carboxylic acid ester compound represented by the general formula (10) has a low freezing point, and when further added to an organic solvent, particularly an organic solvent containing at least one cyclic carbonate compound and at least one chain carbonate compound, even at a low temperature. It is preferable because battery characteristics can be improved. The content of the carboxylic acid ester compound represented by the general formula (10) is preferably 1 to 50% by mass in the organic solvent.

  In addition, acetonitrile, propionitrile, nitromethane, and derivatives thereof can also be used.

  In addition, the non-aqueous electrolyte of the present invention may appropriately contain a halogen-based, phosphorus-based, or other flame retardant in order to impart flame retardancy. Examples of the phosphorus flame retardant include phosphate esters such as trimethyl phosphate and triethyl phosphate.

  5-100 mass% is preferable with respect to the organic solvent which comprises the non-aqueous electrolyte of this invention, and, as for content of the said flame retardant, 10-50 mass% is especially preferable. If it is less than 5% by mass, sufficient flame retarding effect cannot be obtained.

As the electrolyte salt used in the nonaqueous electrolytic solution of the present invention, a conventionally known electrolyte salt is used. For example, LiPF ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiSbF ₆ , LiSiF ₅ , LiAlF ₄ , LiSCN, LiClO ₄ , LiCl, LiF, LiBr, LiI, LiAlCl ₄ , NaClO ₄ , NaBF ₄ , NaI, derivatives thereof, etc. _{among, LiPF 6, LiBF 4, LiClO} 4, LiAsF 6, LiCF 3 SO 3, LiN derivative of (CF ₃ SO _{2) 2} and LiC (CF ₃ SO _{2) 3} and _{LiCF 3 SO 3, LiN (CF} 3 SO _{2) 2} derivative, and LiC (CF ₃ SO ₂₎ to use at least one member selected from the group consisting of ₃ derivatives, electrical JP Since it is excellent in property, it is preferable.

  The electrolyte salt is dissolved in the organic solvent so that the concentration in the non-aqueous electrolyte of the present invention is 0.1 to 3.0 mol / liter, particularly 0.5 to 2.0 mol / liter. It is preferable. If the concentration of the electrolyte salt is less than 0.1 mol / liter, a sufficient current density may not be obtained. If the concentration is more than 3.0 mol / liter, the stability of the nonaqueous electrolyte may be impaired. .

  The nonaqueous electrolytic solution of the present invention can be suitably used as a nonaqueous electrolytic solution constituting a primary or secondary battery, particularly a nonaqueous electrolytic secondary battery described later.

As the electrode material of the battery, there are a positive electrode and a negative electrode. As the positive electrode, a positive electrode active material, a binder, and a conductive material slurried with an organic solvent or water are applied to a current collector, dried, and then a sheet. The one made into a shape is used. Examples of the positive electrode active material include TiS ₂ , TiS ₃ , MoS ₃ , FeS ₂ , Li _(1-x) MnO ₂ , Li _(1-x) Mn ₂ O ₄ , Li _(1-x) CoO ₂ , Li _{(1 -x) NiO 2, LiV 2 O} 3, V 2 O 5 and the like. In addition, X in these positive electrode active materials shows the number of 0-1. A material obtained by adding or substituting a transition metal such as Li, Mg, Al, or Co, Ti, Nb, or Cr may be used. Moreover, not only these lithium-metal composite oxides are used alone, but also a plurality of them can be mixed and used. Among these, the lithium-metal composite oxide is preferably at least one of a lithium manganese-containing composite oxide having a layered structure or a spinel structure, a lithium nickel-containing composite oxide, and a lithium cobalt-containing composite oxide. Examples of the binder for the positive electrode active material include, but are not limited to, polyvinylidene fluoride, polytetrafluoroethylene, EPDM, SBR, NBR, and fluororubber.

  As the negative electrode, a material obtained by applying a slurry obtained by slurrying a negative electrode active material and a binder with an organic solvent or water to a current collector and drying it into a sheet is usually used. Examples of the negative electrode active material include inorganic compounds such as lithium, lithium alloys, and tin compounds, carbonaceous materials, and conductive polymers. In particular, a carbonaceous material that can occlude and release highly safe lithium ions is preferable. The carbonaceous material is not particularly limited, but graphite, petroleum-based coke, coal-based coke, petroleum-based pitch carbide, coal-based pitch carbide, phenolic resin / crystalline cellulose resin carbide, etc., and partially carbonized thereof. Carbon materials, furnace black, acetylene black, pitch-based carbon fibers, PAN-based carbon fibers, and the like. Examples of the binder for the negative electrode active material include the same binders for the positive electrode active material.

  Examples of the conductive material for the positive electrode include fine particles of graphite, carbon black such as acetylene black and ketjen black, fine particles of amorphous carbon such as needle coke, and the like, but are not limited thereto. As the solvent for forming a slurry, an organic solvent that dissolves the binder is usually used. Examples of the organic solvent include N-methylpyrrolidone, dimethylformamide, dimethylacetamide, methyl ethyl ketone, cyclohexanone, methyl acetate, methyl acrylate, diethylenetriamine, NN-dimethylaminopropylamine, tetrahydrofuran, and the like. It is not limited.

  Copper, nickel, stainless steel, nickel-plated steel or the like is usually used for the current collector of the negative electrode, and aluminum, stainless steel, nickel-plated steel or the like is usually used for the current collector of the positive electrode.

  In the non-aqueous electrolyte secondary battery of the present invention, a separator is used between the positive electrode and the negative electrode. As the separator, a commonly used polymer microporous film can be used without any particular limitation. Examples of the film include polyethylene, polypropylene, polyvinylidene fluoride, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polytetrafluoroethylene, polysulfone, polyethersulfone, polycarbonate, polyamide, polyimide, polyethylene oxide and polypropylene oxide. Films composed of ethers, various celluloses such as carboxymethylcellulose and hydroxypropylcellulose, polymer compounds mainly composed of poly (meth) acrylic acid and various esters thereof, derivatives thereof, copolymers and mixtures thereof. Etc. These films may be used alone, or may be used as a multilayer film by superimposing these films. Furthermore, various additives may be used for these films, and the type and content thereof are not particularly limited. Among these films, a film made of polyethylene, polypropylene, polyvinylidene fluoride, or polysulfone is preferably used for the nonaqueous electrolyte secondary battery of the present invention.

  These films are microporous so that the electrolyte can penetrate and ions can easily pass therethrough. The microporosity method includes a phase separation method in which a polymer compound and a solvent solution are formed into a film while microphase separation is performed, and the solvent is extracted and removed to make it porous. The film is extruded and then heat-treated, the crystals are aligned in one direction, and a gap is formed between the crystals by stretching to make it porous, and so on.

  In the non-aqueous electrolyte secondary battery of the present invention, the electrode material, the non-aqueous electrolyte, and the separator include a phenol-based antioxidant, a phosphorus-based antioxidant, and a thioether-based antioxidant for the purpose of improving safety. A hindered amine compound or the like may be added.

  Examples of the phenol-based antioxidant include 1,6-hexamethylene bis [(3-tert-butyl-5-methyl-4-hydroxyphenyl) propionic acid amide], 4,4′-thiobis (6-tert. Tributyl-m-cresol), 4,4′-butylidenebis (6-tert-butyl-m-cresol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate, 1,3,5-tris (3,5-ditert-butyl-4-hydroxybenzyl) ) Isocyanurate, 1,3,5-tris (3,5-ditert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene, tetrakis [3- (3,5-ditert-butyl- 4-hi Roxyphenyl) methyl propionate] methane, thiodiethylene glycol bis [(3,5-ditert-butyl-4-hydroxyphenyl) propionate], 1,6-hexamethylenebis [(3,5-ditert-butyl-4 -Hydroxyphenyl) propionate], bis [3,3-bis (4-hydroxy-3-tert-butylphenyl) butyric acid] glycol ester, bis [2-tert-butyl-4-methyl-6- (2- Hydroxy-3-tert-butyl-5-methylbenzyl) phenyl] terephthalate, 1,3,5-tris [(3,5-ditert-butyl-4-hydroxyphenyl) propionyloxyethyl] isocyanurate, 3,9 -Bis [1,1-dimethyl-2-{(3-tert-butyl-4-hydroxy-5-methylphenyl) propioni Ruoxy} ethyl] -2,4,8,10-tetraoxaspiro [5,5] undecane, triethylene glycol bis [(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate] and the like. When adding to an electrode material, it is preferable to use 0.01-10 mass parts with respect to 100 mass parts of electrode materials, especially 0.05-5 mass parts.

  Examples of the phosphorus antioxidant include trisnonylphenyl phosphite, tris [2-tert-butyl-4- (3-tert-butyl-4-hydroxy-5-methylphenylthio) -5-methylphenyl]. Phosphite, tridecyl phosphite, octyl diphenyl phosphite, di (decyl) monophenyl phosphite, di (tridecyl) pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di Tert-butylphenyl) pentaerythritol diphosphite, bis (2,6-ditert-butyl-4-methylphenyl) pentaerythritol diphosphite, bis (2,4,6-tritert-butylphenyl) pentaerythritol diphosphite Phosphite, bis (2,4-dicumylphenyl) pen Erythritol diphosphite, tetra (tridecyl) isopropylidene diphenol diphosphite, tetra (tridecyl) -4,4′-n-butylidenebis (2-tert-butyl-5-methylphenol) diphosphite, hexa (tridecyl) -1 , 1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane triphosphite, tetrakis (2,4-ditert-butylphenyl) biphenylene diphosphonite, 9,10-dihydro-9 -Oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis (4,6-tert-butylphenyl) -2-ethylhexyl phosphite, 2,2'-methylenebis (4,6- Tributylphenyl) -octadecyl phosphite, 2,2′-ethylidenebis (4,6- Tert-butylphenyl) fluorophosphite, tris (2-[(2,4,8,10-tetrakis tert-butyldibenzo [d, f] [1,3,2] dioxaphosphin-6-yl) Oxy] ethyl) amine, phosphite of 2-ethyl-2-butylpropylene glycol and 2,4,6-tritert-butylphenol, and the like.

  Examples of the thioether-based antioxidant include dialkylthiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, and pentaerythritol tetra (β-alkylmercaptopropionate esters). Is mentioned.

  Examples of the hindered amine compound include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-4-piperidyl stearate, 2,2,6,6. -Tetramethyl-4-piperidylbenzoate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2, 3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, bis (2,2,6,6) -Tetramethyl-4-piperidyl) -di (tridecyl) -1,2,3,4-butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-pi Lysyl) .di (tridecyl) -1,2,3,4-butanetetracarboxylate, bis (1,2,2,4,4-pentamethyl-4-piperidyl) -2-butyl-2- (3,5 -Di-tert-butyl-4-hydroxybenzyl) malonate, 1- (2-hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol / diethyl succinate polycondensate, 1,6- Bis (2,2,6,6-tetramethyl-4-piperidylamino) hexane / 2,4-dichloro-6-morpholino-s-triazine polycondensate, 1,6-bis (2,2,6,6 -Tetramethyl-4-piperidylamino) hexane / 2,4-dichloro-6-tert-octylamino-s-triazine polycondensate, 1,5,8,12-tetrakis [2,4-bis (N-butyl) -N- (2,2,6, -Tetramethyl-4-piperidyl) amino) -s-triazin-6-yl] -1,5,8,12-tetraazadodecane, 1,5,8,12-tetrakis [2,4-bis (N- Butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino) -s-triazin-6-yl] -1,5,8-12-tetraazadodecane, 1,6,11 -Tris [2,4-bis (N-butyl-N- (2,2,6,6-tetramethyl-4-piperidyl) amino) -s-triazin-6-yl] aminoundecane, 1,6,11 Hindered amine compounds such as tris [2,4-bis (N-butyl-N- (1,2,2,6,6-pentamethyl-4-piperidyl) amino) -s-triazin-6-yl] aminoundecane Can be mentioned.

  The shape of the non-aqueous electrolyte secondary battery of the present invention having the above configuration is not particularly limited, and can be various shapes such as a coin shape, a cylindrical shape, and a square shape. FIG. 1 shows an example of a coin-type battery of the nonaqueous electrolyte secondary battery of the present invention, and FIGS. 2 and 3 show examples of a cylindrical battery, respectively.

    In the coin-type non-aqueous electrolyte secondary battery 10 shown in FIG. 1, 1 is a positive electrode capable of releasing lithium ions, 1a is a positive electrode current collector, and 2 is a carbonaceous material capable of inserting and extracting lithium ions released from the positive electrode. The negative electrode current collector, 2a is a negative electrode current collector, 3 is a non-aqueous electrolyte of the present invention, 4 is a stainless steel positive electrode case, 5 is a stainless steel negative electrode case, 6 is a polypropylene gasket, and 7 is a polyethylene separator. It is.

  Further, in the cylindrical nonaqueous electrolyte secondary battery 10 ′ shown in FIGS. 2 and 3, 11 is a negative electrode, 12 is a negative electrode assembly, 13 is a positive electrode, 14 is a positive electrode current collector, and 15 is a non-electrode of the present invention. Water electrolyte, 16 separator, 17 positive electrode terminal, 18 negative electrode terminal, 19 negative electrode plate, 20 negative electrode lead, 21 positive electrode plate, 22 positive electrode lead, 23 case, 24 insulating plate, 25 gasket , 26 are safety valves, and 27 is a PTC element.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples.

  In the examples and comparative examples, nonaqueous electrolyte secondary batteries (lithium secondary batteries) were produced according to the following production procedure.

<Production procedure>
(Preparation of positive electrode)
85 parts by mass of LiNi _0.8 Co _0.17 Al _0.03 O ₂ , 12 parts by mass of acetylene black, 1 part by mass of sodium carboxymethylcellulose (CMC), 1 part by mass of polyethylene oxide (PEO), 80 parts by mass of water 1 part by mass of polytetrafluoroethylene (PTFE) was further added and dispersed as a binder to form a slurry. This slurry was applied to both sides of a positive electrode current collector made of aluminum, dried and press-molded to obtain a positive electrode plate. Then, this positive electrode plate was cut into a predetermined size, and a sheet-like positive electrode was produced by scraping off the electrode mixture at a portion that became a lead tab weld for extracting current.

(Preparation of negative electrode)
98 parts by mass of graphite carbon material powder as a negative electrode active material and 1 part by mass of sodium carboxymethylcellulose (CMC) are dispersed in 98 parts by mass of water, and further 1 styrene butadiene rubber (SBR) is used as a binder. Mass parts were added and dispersed to obtain a slurry. This slurry was applied to both sides of a copper negative electrode current collector, dried and press-molded to obtain a negative electrode plate. Then, this negative electrode plate was cut into a predetermined size, and a sheet-like negative electrode was produced by scraping off the electrode composite material at a portion to be a lead tab weld for extracting current.

(Preparation of non-aqueous electrolyte)
The organic solvent is mixed in the blending amount (volume%) shown in the Examples and Comparative Examples described below, and LiPF ₆ is dissolved at a concentration of 1 mol / liter, and the test compound (described in Table 1) is blended as described in Table 1. It was added in an amount (mass%) to obtain a non-aqueous electrolyte.

(Battery assembly)
The obtained sheet-like positive electrode and sheet-like negative electrode were wound through a polyethylene microporous film having a thickness of 25 μm to form a wound electrode body. The obtained wound electrode body was inserted into the case and held in the case. At this time, the current collecting lead having one end welded to the lead tab weld portion of the sheet-like positive electrode or sheet-like negative electrode was joined to the positive electrode terminal or the negative electrode terminal of the case, respectively. Thereafter, a non-aqueous electrolyte was poured into the case holding the wound electrode body, and the case was sealed and sealed to produce a cylindrical lithium secondary battery having a diameter of 18 mm and an axial length of 65 mm.

[Examples and Comparative Examples]
LiPF ₆ was dissolved in a mixed solvent consisting of 25% by volume of ethylene carbonate, 40% by volume of ethyl methyl carbonate, 30% by volume of dimethyl carbonate, and 5% by volume of diethyl carbonate to give a test compound (see Table 1). ) Was added to obtain a non-aqueous electrolyte. A lithium secondary battery was prepared using the non-aqueous electrolyte, and the lithium secondary battery was subjected to a cycle characteristic test and an 80 ° C. storage test according to the following test method. In the cycle characteristic test and the 80 ° C. storage test, the discharge capacity retention rate (%) and the internal resistance ratio were determined. Test methods for the cycle characteristic test and the 80 ° C. storage test are as follows.

<Cycle characteristic test method>
The lithium secondary battery is placed in a constant temperature bath at an atmospheric temperature of 60 ° C., and the charging current is 2.2 mA / cm ² (current value corresponding to 2C, 1C is a current value for discharging the battery capacity in 1 hour) up to 4.1V. A cycle in which constant current charging was performed and constant current discharging was performed up to 3 V at a discharge current of 2.2 mA / cm ² (current value corresponding to 2C) was repeated 500 times. Thereafter, the ambient temperature is returned to 20 ° C., and constant current and constant voltage charging is performed up to 4.1 V with a charging current of 1.1 mA / cm ² (current value corresponding to 1 C), and a discharge current of 0.33 mA / cm ² (1/3 C). The discharge capacity maintenance rate (%) was obtained from the following formula from the discharge capacity and the initial discharge capacity. Further, before and after the above 500 cycles, the internal resistance at 20 ° C. was measured, and the internal resistance ratio was determined from the measurement result by the following formula. The initial discharge capacity and internal resistance of the lithium secondary battery were measured by the following measuring methods.

Discharge capacity retention rate (%) = [(discharge capacity after cycle) / (initial discharge capacity)] × 100
Internal resistance ratio = “(Internal resistance after cycle) / (Internal resistance before cycle in Example 1)]
× 100

<Initial discharge capacity measurement method>
First, a constant current and constant voltage charge was performed up to 4.1 V at a charging current of 0.25 mA / cm ² (current value corresponding to 1 / 4C), and 3 at a discharge current of 0.33 mA / cm ² (current value corresponding to 1 / 3C). A constant current discharge was performed up to 0.0V. Then, constant current constant voltage to 4.1V at a charging current 1.1 mA / cm ² (current value of 1C equivalent) charged, up to 3.0V discharge current 1.1 mA / cm ² (current value of 1C equivalent) The operation of discharging with constant current was performed 4 times. Thereafter, 3.0 V at a charging current 1.1 mA / cm ² at (1C equivalent current value) to 4.1V charging constant current constant voltage, discharge current 0.33mA / cm ² (1 / 3C equivalent current value) The discharge capacity at this time was defined as the initial battery capacity. The measurement was performed in an atmosphere at 20 ° C.

<Internal resistance measurement method>
First, a constant current and constant voltage charge to 3.75 V was performed at a charging current of 1.1 mA / cm ² (current value equivalent to 1 C), and an AC impedance measurement device (manufactured by Toyo Technica: frequency response analyzer solartron 1260, potentio / galvanostat) Using a solartron 1287), scanning was performed from a frequency of 100 kHz to 0.02 Hz, and a Cole-Cole plot showing the imaginary part on the vertical axis and the real part on the horizontal axis was created. Subsequently, in this Cole-Cole plot, the arc part was fitted with a circle, and the larger value of the two points intersecting the real part of this circle was taken as the resistance value, and the battery internal resistance.

<80 ° C storage test method>
The fully charged lithium secondary battery was stored in a thermostat having an atmospheric temperature of 80 ° C. Thereafter, the atmospheric temperature was returned to 20 ° C., and the discharge capacity and the internal resistance were measured.

  Table 1 shows the test results of the cycle characteristic test and the low temperature characteristic evaluation test.

  As is apparent from the results of [Table 1], the unsaturated compound represented by any one of the general formulas (1), (2), (3) and (4) as the component A and the unsaturated component as the component B It was confirmed that the non-aqueous electrolyte secondary battery using the non-aqueous electrolyte of the present invention to which a cyclic carbonate compound containing a group was added was excellent in cycle characteristics and high-temperature storage characteristics. On the other hand, when only component A is added or when only component B is added, the cycle characteristics and the high-temperature storage characteristics are compared with the non-aqueous electrolyte secondary battery using the non-aqueous electrolyte of the present invention. It was inferior.

Industrial applicability

  By using the non-aqueous electrolyte of the present invention, a non-aqueous electrolyte secondary battery having excellent cycle characteristics and high-temperature storage characteristics can be provided.

FIG. 1 is a longitudinal sectional view schematically showing an example of the structure of a coin-type battery of the nonaqueous electrolyte secondary battery of the present invention. FIG. 2 is a schematic diagram showing a basic configuration of a cylindrical battery of the nonaqueous electrolyte secondary battery of the present invention. FIG. 3 is a perspective view showing the internal structure of the cylindrical battery of the nonaqueous electrolyte secondary battery of the present invention as a cross section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Positive electrode 1a Positive electrode collector 2 Negative electrode 2a Negative electrode collector 3 Electrolytic solution 4 Positive electrode case 5 Negative electrode case 6 Gasket 7 Separator 10 Coin type nonaqueous electrolyte secondary battery 10 'Cylindrical type nonaqueous electrolyte secondary battery DESCRIPTION OF SYMBOLS 11 Negative electrode 12 Negative electrode assembly 13 Positive electrode 14 Positive electrode assembly 15 Electrolytic solution 16 Separator 17 Positive electrode terminal 18 Negative electrode terminal 19 Negative electrode plate 20 Negative electrode lead 21 Positive electrode 22 Positive electrode lead 23 Case 24 Insulating plate 25 Gasket 26 Safety valve 27 PTC element

Claims (7)

In an electrolytic solution in which an electrolyte salt is dissolved in an organic solvent, it contains both the component (a) and the component (b), and the component (a) is represented by the following general formula (1), (2), (3) or (4 ) Containing at least one kind selected from unsaturated bond-containing compounds represented by any one of the above), and the component (b) is a cyclic carbonate compound containing an unsaturated group. Non-aqueous electrolyte.

Wherein M represents a Si, Ge or Sn atom, A represents a direct bond or an alkylene group having 1 to 8 carbon atoms, and R ₁ and R ₂ are each independently substituted with a halogen atom. An optionally substituted alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or an aryl group having 6 to 18 carbon atoms which may be substituted with a halogen atom, and R ₃ represents the number of carbon atoms 1 represents an alkylene group having 1 to 8 or —CO—B—CO—, B represents a direct bond or an alkylene group having 1 to 8 carbon atoms, R ₄ represents an alkylene group having 1 to 8 carbon atoms, carbon An alylene group having 2 to 8 atoms or an arylene group having 6 to 8 carbon atoms which may be substituted with a halogen atom is shown.)   The non-aqueous electrolyte according to claim 1, wherein the cyclic carbonate compound containing an unsaturated group is vinylene carbonate or vinyl ethylene carbonate.   The non-aqueous electrolyte according to claim 1 or 2, wherein a mass ratio of the content of the component (A) and the content of the component (B) is 50: 100 to 1: 100.   The non-aqueous solution according to any one of claims 1 to 3, wherein the total content of the component (a) and the component (b) is 0.05 to 20% by mass in the non-aqueous electrolyte. Electrolytic solution. The component (c) further contains at least one silicon compound represented by the following general formula (5), (6), (7), (8) or (9). The non-aqueous electrolyte in any one of -4.

(Wherein R ₅ , R ₆ and R ₇ are each independently an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, an alkyl group or a halogen atom which may be substituted with a halogen atom) An aryl group having 6 to 18 carbon atoms which may be substituted with an atom, R ₈ represents an alkylene group having 1 to 8 carbon atoms, and R ₉ represents an alkenyl group having 2 to 8 carbon atoms. m is 1 or 2, and when m is 1, X represents a fluoro group, a trifluoromethyl group, an alkoxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or 2 to 8 carbon atoms. An alkenyloxy group, an aryloxy group having 6 to 8 carbon atoms which may be substituted with a halogen atom, an acyloxy group having 2 to 8 carbon atoms which may be substituted with a halogen atom, or a carbon which may be substituted with a halogen atom A sulfonate group having 1 to 8 atoms, Represents a socyanyl group, an isothiocyanyl group or a cyano group, and when m is 2, X is substituted with a direct bond, an oxygen atom, an alkylene group having 1 to 8 carbon atoms which may be substituted with a halogen atom, or a halogen atom. C1-C8 alkylenedioxy group, C2-C8 alkenylene group, C2-C8 alkenylene dioxy group, C2-C8 alkynylene group, carbon atoms 2-8 alkynylene dioxy groups, arylene groups of 6-8 carbon atoms that may be substituted with halogen atoms, aryleneoxy groups of 6-8 carbon atoms that may be substituted with halogen atoms, or carbon atoms A diacyloxy group having a number of 2 to 8. Y represents a fluoro group, a trifluoromethyl group, a vinyl group, an alkoxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom, a carbon atom Alkenyloxy group having 2 to 8 carbon atoms, aryl group having 6 to 18 carbon atoms which may be substituted with a halogen atom, aryloxy group having 6 to 8 carbon atoms which may be substituted with a halogen atom, substituted with a halogen atom And an acyloxy group having 2 to 8 carbon atoms, a sulfonate group having 1 to 8 carbon atoms which may be substituted with a halogen atom, an isocyanyl group, an isothiocyanyl group or a cyano group, Z is a direct bond, oxygen An atom, an alkylene group having 1 to 8 carbon atoms which may be substituted with a halogen atom, an alkylenedioxy group having 1 to 8 carbon atoms which may be substituted with a halogen atom, an alkenylene group having 2 to 8 carbon atoms, It may be substituted with an alkenylene dioxy group having 2 to 8 carbon atoms, an alkynylene group having 2 to 8 carbon atoms, an alkynylene dioxy group having 2 to 8 carbon atoms, or a halogen atom. Arylene group atom 6-8 shows the arylenedioxy group or diacyloxy group having 2 to 8 carbon atoms of 6 to 8 carbon atoms which may be substituted with a halogen atom. )   The non-aqueous electrolyte solution according to any one of claims 1 to 5, wherein the content of the component (c) is 0.05 to 20% by mass in the non-aqueous electrolyte solution.   A nonaqueous electrolyte secondary battery comprising the nonaqueous electrolyte solution according to any one of claims 1 to 6 as an electrolyte solution.

Images