JP5239473B2 - Secondary battery electrolyte, secondary battery and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary battery capable of enhancing cycle characteristics and a preservation property. <P>SOLUTION: The secondary battery is provided with a cathode 21 and an anode 22 together with the electrolyte solution impregnated in a separator 23 fitted between the cathode 21 and the anode 22. The solvents of the electrolyte solution include nitrile compound containing a site where a nitrile group and an electron-attracting group (such as -C(=O)-) are directly coupled with each other. As compared with the case in which no such nitrile compounds are contained, or other nitrile compounds are contained, chemical stability of the electrolyte solution is improved, so that decomposition reaction of the electrolyte solution is restrained at charging and discharging. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention is an electrolyte solution for a secondary battery comprising a solvent, an electronic apparatus including a secondary battery and it using the same.

  In recent years, portable electronic devices such as video cameras, mobile phones, and notebook computers have been widely used, and there is a strong demand for miniaturization, weight reduction, and long life. Accordingly, as a power source for portable electronic devices, development of a battery, in particular, a secondary battery that is lightweight and capable of obtaining a high energy density is underway.

  Among them, secondary batteries that use the insertion and extraction of lithium for charge / discharge reactions (so-called lithium ion secondary batteries) and secondary batteries that use precipitation and dissolution of lithium (so-called lithium metal secondary batteries) are lead batteries. It is highly anticipated because it has a higher energy density than nickel cadmium batteries.

Regarding the composition of the electrolytic solution used in these secondary batteries, a technique using a compound (nitrile compound) having a nitrile group (or cyano group: -CN) has been proposed in order to improve battery characteristics such as cycle characteristics. ing. As this nitrile compound, those having a cyanoethyl group (for example, see Patent Document 1) and those having a plurality of nitrile groups (for example, see Patent Document 2) are used. In addition, about the composition of electrolyte solution, the compound (sulfone compound) etc. which have a sulfonyl group (-S (= O) _2- ) other than the above-mentioned nitrile compound are used (for example, refer patent document 3). .
JP 2000-243442 A JP 2007-149535 A JP 2007-273395 A

  In recent years, portable electronic devices have become more sophisticated and multifunctional, and their power consumption tends to increase. Therefore, charging and discharging of secondary batteries are frequently repeated, and the cycle characteristics are likely to deteriorate. . In addition, portable electronic devices are widely used in various fields, and secondary batteries can be exposed to high-temperature atmosphere during transportation, use, or carrying, so their storage characteristics are likely to deteriorate. Is in the situation. For this reason, the further improvement is desired regarding the cycling characteristics and storage characteristics of a secondary battery.

The present invention has been made in view of such problems, and an object thereof is to provide an electrolyte solution for a secondary battery , a secondary battery, and an electronic device that can improve cycle characteristics and storage characteristics.

The electrolytic solution for a secondary battery of the present invention includes a non-aqueous solvent containing at least one of nitrile compounds represented by Chemical Formula 1.

（Ｒは炭素（Ｃ）と水素（Ｈ）およびハロゲンのうちの少なくとも一方とを構成元素として有するｚ価の有機基であり、Ｘは−Ｃ（＝Ｏ）−、−Ｏ−Ｃ（＝Ｏ）−、−Ｓ（＝Ｏ）−、−Ｏ−Ｓ（＝Ｏ）−、−Ｓ（＝Ｏ）₂ −、あるいは−Ｏ−Ｓ（＝Ｏ）₂ −であり、ｚは１以上の整数である。ただし、ＸはＲ中の炭素原子に結合している。）

(R is a z-valent organic group having carbon (C) and at least one of hydrogen (H) and halogen as constituent elements , and X is -C (= O)-, -O-C (= O )-, -S (= O)-, -OS (= O)-, -S (= O) _2- , or -O-S (= O) _2- , and z is an integer of 1 or more. However, X is bonded to a carbon atom in R.)

The secondary battery of the present invention includes an electrolyte solution together with a positive electrode and a negative electrode, and the electrolyte solution includes a nonaqueous solvent containing at least one of nitrile compounds represented by Chemical Formula 2. The electronic device of the present invention includes the secondary battery of the present invention.

（Ｒは炭素と水素およびハロゲンのうちの少なくとも一方とを構成元素として有するｚ価の有機基であり、Ｘは−Ｃ（＝Ｏ）−、−Ｏ−Ｃ（＝Ｏ）−、−Ｓ（＝Ｏ）−、−Ｏ−Ｓ（＝Ｏ）−、−Ｓ（＝Ｏ）₂ −、あるいは−Ｏ−Ｓ（＝Ｏ）₂ −であり、ｚは１以上の整数である。ただし、ＸはＲ中の炭素原子に結合している。）

(R is a z-valent organic group having carbon and at least one of hydrogen and halogen as constituent elements , and X is —C (═O) —, —O—C (═O) —, —S ( ═O) —, —O—S (═O) —, —S (═O) ₂ —, or —O—S (═O) ₂ —, and z is an integer of 1 or more, where X Is bonded to a carbon atom in R.)

As an example of the above-mentioned “organic group” , examples of the “monovalent organic group” include an alkyl group, an aryl group, a halogenated alkyl group, and a halogenated aryl group. Examples of the “group” include an alkylene group and a halogenated alkylene group.

According to the secondary battery electrolyte solution of the present invention, the non-aqueous solvent contains at least one of the nitrile compounds shown in Chemical Formula 1; Chemical stability is improved as compared with the case of containing a nitrile compound. Therefore, according to the secondary battery using the electrolytic solution for the secondary battery of the present invention and the electronic device equipped with the secondary battery, since the decomposition reaction of the electrolytic solution is suppressed during charging and discharging, cycle characteristics and storage characteristics are improved. Can be made.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  An electrolytic solution according to an embodiment of the present invention is used for an electrochemical device such as a secondary battery, and includes a solvent and an electrolyte salt dissolved in the solvent.

  The solvent contains at least one of the nitrile compounds represented by Chemical formula 3. This is because the chemical stability of the electrolytic solution is improved as compared with the case where this nitrile compound is not contained or the case where other nitrile compounds are contained. The nitrile compound shown in Chemical Formula 3 is a chain compound having one or more sites where a nitrile group (—CN) and an electron-withdrawing group (X) are directly bonded.

（Ｒはｚ価の有機基であり、Ｘは−Ｃ（＝Ｏ）−、−Ｏ−Ｃ（＝Ｏ）−、−Ｓ（＝Ｏ）−、−Ｏ−Ｓ（＝Ｏ）−、−Ｓ（＝Ｏ）₂ −、あるいは−Ｏ−Ｓ（＝Ｏ）₂ −であり、ｚは１以上の整数である。ただし、ＸはＲ中の炭素原子に結合している。）

(R is a z-valent organic group, X is —C (═O) —, —O—C (═O) —, —S (═O) —, —O—S (═O) —, — S (═O) ₂ — or —O—S (═O) ₂ —, and z is an integer of 1 or more, provided that X is bonded to a carbon atom in R.)

  The “z-valent organic group” described for R in Chemical Formula 3 is a general term for a z-valent group having a carbon chain or carbocycle as a basic skeleton. The “z-valent organic group” may be a group having any structure as a whole as long as it has a carbon chain or a carbocyclic ring as a basic skeleton. Or you may have 2 or more types as a structural element. Examples of the “other elements” include hydrogen, oxygen, and halogen. The carbon chain described above may be linear or branched having one or more side chains.

  The above-mentioned “other elements” may be included in any form in the “organic group”. The “form” means the number or combination of elements and can be arbitrarily set. Specifically, examples of the form containing hydrogen include an alkyl group, a vinyl group, an aryl group, an alkylene group, a vinylene group, and an arylene group. Examples of the form containing oxygen include an oxo group (—O—). Examples of the form containing halogen include a halogenated alkyl group, a halogenated vinyl group, a halogenated aryl group, a halogenated alkylene group, a halogenated vinylene group, and a halogenated arylene group. The type of this halogen can be arbitrarily set. Of course, the form including “other elements” may be other forms than the above.

  However, in Chemical formula 3, X is not bonded to atoms other than carbon atoms in R (for example, oxygen atoms), but is always bonded to carbon atoms.

  R may be a derivative of a group constituted by the series of forms described above. This “derivative” means a group in which one or two or more substituents are introduced into the above-described series of groups, and the type of the substituents can be arbitrarily set.

  The number of carbon atoms in R is not particularly limited, but is preferably not excessively large, and more preferably as small as possible. This is because the solubility and compatibility of the nitrile compound are increased, so that the nitrile compound is stably mixed with an organic solvent or the like.

  R may be any group as long as it is a group constituted by the series of forms described above. A specific example of this R will be described in detail when referring to Chemical Formulas 4 to 6 described later.

In addition, among X in Chemical Formula 3, those having an asymmetric structure (—O—C (═O) —, —O—S (═O) —, —O—S (═O) ₂ —) The oxo group (—O—) may be bonded to either R or a nitrile group. That is, when the case where X is —O—C (═O) — and z is z = 1 is described as an example, the structure of the nitrile compound shown in Chemical Formula 3 is R—O—C ( ═O) —CN or R—C (═O) —O—CN. The same applies to —O—S (═O) — or —O—S (═O) ₂ —. However, if anything, the oxo group is preferably bonded to R. This is because it is easily available and high chemical stability can be obtained in the electrolytic solution.

  Especially, it is preferable that the nitrile compound shown to Chemical formula 3 is a compound represented by Chemical formula 4-6. This is because high chemical stability can be obtained in the electrolytic solution.

（Ｒ１は１価の有機基であり、Ｘ１は−Ｃ（＝Ｏ）−、−Ｏ−Ｃ（＝Ｏ）−、−Ｓ（＝Ｏ）−、−Ｏ−Ｓ（＝Ｏ）−、−Ｓ（＝Ｏ）₂ −、あるいは−Ｏ−Ｓ（＝Ｏ）₂ −である。ただし、Ｘ１はＲ１中の炭素原子に結合している。）

(R1 is a monovalent organic group, X1 is —C (═O) —, —O—C (═O) —, —S (═O) —, —O—S (═O) —, — S (= O) ₂ — or —O—S (═O) ₂ —, wherein X 1 is bonded to the carbon atom in R 1.

（Ｒ２は２価の有機基であり、Ｘ２は−Ｃ（＝Ｏ）−、−Ｏ−Ｃ（＝Ｏ）−、−Ｓ（＝Ｏ）−、−Ｏ−Ｓ（＝Ｏ）−、−Ｓ（＝Ｏ）₂ −、あるいは−Ｏ−Ｓ（＝Ｏ）₂ −である。ただし、Ｘ２はＲ２中の炭素原子に結合している。）

(R2 is a divalent organic group, and X2 is —C (═O) —, —O—C (═O) —, —S (═O) —, —O—S (═O) —, — S (= O) ₂ — or —O—S (═O) ₂ —, wherein X 2 is bonded to the carbon atom in R 2.

（Ｒ３は（ｚ１＋ｚ２）価の有機基であり、Ｘ３およびＸ４は−Ｃ（＝Ｏ）−、−Ｏ−Ｃ（＝Ｏ）−、−Ｓ（＝Ｏ）−、−Ｏ−Ｓ（＝Ｏ）−、−Ｓ（＝Ｏ）₂ −、あるいは−Ｏ−Ｓ（＝Ｏ）₂ −であり、ｚ１およびｚ２は１以上の整数である。ただし、Ｘ３およびＸ４は異なる種類であり、それらはＲ３中の炭素原子に結合している。）

(R3 is a (z1 + z2) -valent organic group, and X3 and X4 are —C (═O) —, —O—C (═O) —, —S (═O) —, —O—S (═O ) —, —S (═O) ₂ —, or —O—S (═O) ₂ —, and z1 and z2 are integers of 1 or more, provided that X3 and X4 are different types, It is bonded to the carbon atom in R3.)

  The compound shown in Chemical formula 4 is a compound in which R in Chemical formula 3 is a monovalent group (R1) and z is z = 1. The compound shown in Chemical Formula 4 has only one site where the nitrile group and the electron-withdrawing group (X1) are directly bonded, and the kind of the electron-withdrawing group is one (X1). . If the nitrile compound shown in Chemical formula 3 is a compound shown in Chemical formula 4, the number of z (the number of sites where the isocyanate group and the electron-withdrawing group are directly bonded) can be minimized, which is preferable. As a result, when the nitrile compound is mixed with other solvents and used in the electrolyte, excellent compatibility is obtained and the nitrile compound reacts (decomposes) preferentially during the electrode reaction. This suppresses the decomposition reaction of other solvents and the like.

  R1 in Chemical Formula 4 may have any structure as long as it is a monovalent organic group, similarly to the case described for R in Chemical Formula 3. As R1 which is a monovalent organic group, for example, a linear or branched alkyl group, an aryl group, a group in which an alkyl group and an oxo group are bonded (alkoxy group), or halogenated thereof. Groups and derivatives thereof. The “group in which they are halogenated” is a group in which at least a part of the above-described alkyl groups and the like are substituted with halogen. The type of the halogen is not particularly limited, but among them, fluorine is preferable. This is because a high effect can be obtained. Of course, R1 may be a group other than the series of groups described above.

  Among these, R 1 is preferably an alkyl group having 1 to 10 carbon atoms, an aryl group, a halogenated alkyl group having 1 to 10 carbon atoms, a halogenated aryl group, or a derivative thereof. This is because high chemical stability can be obtained in the electrolytic solution and excellent compatibility can be obtained. In addition, when R1 is an alkyl group or a halogenated alkyl group, the number of carbon atoms is more preferably 1 or more and 5 or less. This is because a higher effect can be obtained.

Specific examples of the compound represented by Chemical formula 4 include compounds represented by Chemical formulas 7 to 18. The types of X1 are —C (═O) — in Chemical Formula 7 and Chemical Formula 8, —O—C (═O) — in Chemical Formula 9 and Chemical Formula 10, and —S (═O) — in Chemical Formula 11 and Chemical Formula 12. In Formula 13 and Formula 14, —O—S (═O) —, in Formula 15 and Formula 16 are —S (═O) ₂ —, and in Formula 17 and Formula 18 are —O—S (═O) ₂ —.

  The compound shown in Chemical formula 5 is a compound in which R in Chemical formula 3 is a divalent group (R2) and z is z = 2. The compound shown in Chemical formula 5 has two sites in which a nitrile group and an electron-withdrawing group (X2) are directly bonded, and there is one kind of electron-withdrawing group (X2). If the nitrile compound shown in Chemical formula 3 is a compound shown in Chemical formula 5, the number of z can be kept small, so that, as with the compound shown in Chemical formula 4, excellent compatibility can be obtained, and at the time of electrode reaction Decomposition reaction of other solvents and the like is suppressed.

  R2 in Chemical Formula 5 may have any structure as long as it is a divalent organic group, similarly to the case described for R in Chemical Formula 3. Examples of R2 that is a divalent organic group include a linear or branched alkylene group, an arylene group, a group in which an arylene group and an alkylene group are bonded, and an alkylene group and an oxo group. Groups, halogenated groups thereof, and derivatives thereof. The “divalent group in which an arylene group and an alkylene group are bonded” may be a group in which one arylene group and one alkylene group are bonded, or two alkylene groups may be one arylene group. It may be a group bonded via The “group in which an alkylene group and an oxo group are bonded” means a group in which two alkylene groups are bonded through one ether bond. Further, the “group in which they are halogenated” is a group in which at least a part of hydrogen in the above-described alkylene group or the like is substituted with a halogen. The type of the halogen is not particularly limited, but among them, fluorine is preferable. This is because a high effect can be obtained. The number and bonding order of the above-described alkylene group, arylene group, oxo group and the like can be arbitrarily set. Of course, R2 may be a group other than the series of groups described above.

  Specific examples of R2 include linear alkylene groups represented by chemical formulas (1) to (8), branched alkylene groups represented by chemical formulas (1) to (9), An arylene group represented by (1) to (3) in Chemical Formula 21, a group in which an arylene group represented by (1) to (3) in Chemical Formula 22 is bonded to an alkylene group, or (1 ) To (13) and a group in which an alkylene group and an oxo group are bonded. In addition, as a group obtained by halogenating the above-described series of groups, a group in which a group in which an alkylene group and an oxo group are bonded is halogenated, as represented by the formulas (1) to (9). It is done. Of course, it is not limited to a group in which an alkylene group and an oxo group are bonded, and other alkylene groups and the like may be halogenated.

  Among these, R2 is preferably a linear alkylene group or a linear halogenated alkylene group. This is because high chemical stability can be obtained in the electrolytic solution and excellent compatibility can be obtained. In this case, the carbon number is preferably 1 or more and 4 or less, and more preferably 1 or more and 3 or less. This is because a higher effect can be obtained.

Specific examples of the compound represented by Chemical formula 5 include compounds represented by Chemical formula 25 to Chemical formula 30. The types of X2 are —C (═O) — in Chemical Formula 25, —O—C (═O) — in Chemical Formula 26, —S (═O) — in Chemical Formula 27, and —O—S (═O in Chemical Formula 28). ) -, of 29 in -S (= O) ₂ -, in formula 30 -O-S (= O) 2 - a.

  The compound shown in Chemical formula 6 is a compound in which R in Chemical formula 3 is a (z1 + z2) -valent group (R3) and z is (z1 + z2). The compound shown in Chemical formula 6 has one or more sites where the nitrile group and the electron-withdrawing group (X3) are directly bonded, and the nitrile group and the electron-withdrawing group (X4) have It has one or more directly bonded sites, and there are two types (X3, X4) of electron-withdrawing groups. If the nitrile compound shown in Chemical formula 3 is a compound shown in Chemical formula 6, since it has different types of electron-withdrawing groups, excellent compatibility can be obtained, and decomposition reaction of other solvents and the like can occur during the electrode reaction. It is suppressed.

  R3 in Chemical Formula 6 may have any structure as long as it is an organic group having a (z1 + z2) valence, similarly to the case described for R in Chemical Formula 3. For example, when z1 = 1 and z2 = 1 and R3 is a divalent organic group, examples of R3 include the same groups as R2 in Chemical Formula 5.

Specific examples of the compound shown in Chemical formula 6 include the compound represented by Chemical formula 31. The types of X3 and X4 are -C (= O)-and -S (= O)-in the formulas (1) to (5), and -C (= O in the formulas (6) to (10). )-And -S (= O) _2- .

  Of course, as long as the nitrile compound has the structure shown in Chemical Formula 3, it is needless to say that the nitrile compound is not limited to those having the structures shown in Chemical Formulas 4 to 31. In this case, for a compound having a geometric isomer, the geometric isomer is also included in the nitrile compound.

  The content of the nitrile compound shown in Chemical Formula 3 in the solvent is not particularly limited, but is preferably 0.01% by weight or more and 10% by weight or less. This is because high chemical stability can be obtained in the electrolytic solution. Specifically, if the content is less than 0.01% by weight, the chemical stability of the electrolytic solution may not be obtained sufficiently and stably. If the content is more than 10% by weight, the electrochemical There is a possibility that the main electrical performance of the device (for example, the battery capacity in the secondary battery) may decrease.

  This solvent may contain any one kind or two or more kinds of nonaqueous solvents such as other organic solvents together with the nitrile acid compound shown in Chemical formula 3. The series of solvents described below may be arbitrarily combined.

  Examples of the non-aqueous solvent include ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2 -Methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, butyric acid Methyl, methyl isobutyrate, methyl trimethylacetate, ethyl trimethylacetate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N, N-dimethylformamide, N-methylpyrrolidinone, N-methyl Examples thereof include tiloxazolidinone, N, N′-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, and dimethyl sulfoxide. Among these, at least one selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate is preferable. In this case, a high viscosity (high dielectric constant) solvent such as ethylene carbonate or propylene carbonate (for example, a relative dielectric constant ε ≧ 30) and a low viscosity solvent such as dimethyl carbonate, ethyl methyl carbonate or diethyl carbonate (for example, viscosity ≦ 1 mPas). -A combination with s) is more preferred. This is because the dissociation property of the electrolyte salt and the ion mobility are improved.

  In particular, the solvent contains at least one of a chain carbonate ester having a halogen represented by Chemical Formula 32 as a constituent element and a cyclic carbonate ester having a halogen represented by Chemical Formula 33 as a constituent element. preferable. This is because a stable protective film is formed on the surface of the electrode during the electrode reaction of the electrochemical device, so that the decomposition reaction of the electrolytic solution is suppressed.

（Ｒ１１〜Ｒ１６は水素基、ハロゲン基、アルキル基あるいはハロゲン化アルキル基であり、それらのうちの少なくとも１つはハロゲン基あるいはハロゲン化アルキル基である。）

(R11 to R16 are a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, and at least one of them is a halogen group or a halogenated alkyl group.)

（Ｒ１７〜Ｒ２０は水素基、ハロゲン基、アルキル基あるいはハロゲン化アルキル基であり、それらのうちの少なくとも１つはハロゲン基あるいはハロゲン化アルキル基である。）

(R17 to R20 are a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, and at least one of them is a halogen group or a halogenated alkyl group.)

  R11 to R16 in Chemical formula 32 may be the same or different. That is, the types of R11 to R16 can be individually set within the above-described series of groups. The same applies to R17 to R20 in Chemical Formula 33.

  The kind of halogen is not particularly limited, but among them, fluorine, chlorine or bromine is preferable, and fluorine is more preferable. This is because a higher effect can be obtained as compared with other halogens.

  However, the number of halogens is preferably two rather than one, and may be three or more. This is because the ability to form a protective film is increased and a stronger and more stable protective film is formed, so that the decomposition reaction of the electrolytic solution is further suppressed.

  Examples of the chain ester carbonate having a halogen shown in Chemical formula 32 include fluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, difluoromethyl methyl carbonate, and the like. These may be single and multiple types may be mixed. Of these, bis (fluoromethyl) carbonate is preferred. This is because a high effect can be obtained.

  Examples of the cyclic carbonate having a halogen shown in Chemical formula 33 include a series of compounds represented by Chemical formula 34 and Chemical formula 35. That is, 4-fluoro-1,3-dioxolan-2-one of (1) shown in Chemical formula 34, 4-chloro-1,3-dioxolan-2-one of (2), 4,5 of (3) -Difluoro-1,3-dioxolan-2-one, (4) tetrafluoro-1,3-dioxolan-2-one, (5) 4-chloro-5-fluoro-1,3-dioxolan-2-one ON, (6) 4,5-dichloro-1,3-dioxolan-2-one, (7) tetrachloro-1,3-dioxolan-2-one, (8) 4,5-bistrifluoromethyl 1,3-dioxolan-2-one, 4-trifluoromethyl-1,3-dioxolan-2-one of (9), 4,5-difluoro-4,5-dimethyl-1,3 of (10) -Dioxolan-2-one, 4,4-difluoro of (11) -5-methyl-1,3-dioxolan-2-one, and the like 5,5-difluoro-1,3-dioxolan-2-one (12). Further, 4-fluoro-5-trifluoromethyl-1,3-dioxolan-2-one of (1) shown in Chemical formula 35, 4-methyl-5-trifluoromethyl-1,3-dioxolane of (2) 2-one, 4-fluoro-4,5-dimethyl-1,3-dioxolan-2-one of (3), 5- (1,1-difluoroethyl) -4,4-difluoro- of (4) 1,3-dioxolan-2-one, 4,5-dichloro-4,5-dimethyl-1,3-dioxolan-2-one in (5), 4-ethyl-5-fluoro-1, in (6) 3-dioxolan-2-one, 4-ethyl-4,5-difluoro-1,3-dioxolan-2-one of (7), 4-ethyl-4,5,5-trifluoro-1 of (8) , 3-Dioxolan-2-one, 4-fluoro-4-methyl- of (9) , 3-dioxolane-2-one. These may be single and multiple types may be mixed.

  Of these, 4-fluoro-1,3-dioxolan-2-one or 4,5-difluoro-1,3-dioxolan-2-one is preferred, and 4,5-difluoro-1,3-dioxolan-2-one is preferred. More preferred. In particular, 4,5-difluoro-1,3-dioxolan-2-one is preferably a trans isomer rather than a cis isomer. This is because it is easily available and a high effect can be obtained.

  Further, the solvent preferably contains a cyclic carbonate having an unsaturated bond represented by Chemical Formula 36 to Chemical Formula 38. This is because the chemical stability of the electrolytic solution is further improved. These may be single and multiple types may be mixed.

（Ｒ２１およびＲ２２は水素基あるいはアルキル基である。）

(R21 and R22 are a hydrogen group or an alkyl group.)

（Ｒ２３〜Ｒ２６は水素基、アルキル基、ビニル基あるいはアリル基であり、それらのうちの少なくとも１つはビニル基あるいはアリル基である。）

(R23 to R26 are a hydrogen group, an alkyl group, a vinyl group, or an allyl group, and at least one of them is a vinyl group or an allyl group.)

（Ｒ２７はアルキレン基である。）

(R27 is an alkylene group.)

  The cyclic carbonate having an unsaturated bond shown in Chemical formula 36 is a vinylene carbonate-based compound. Examples of the vinylene carbonate compound include vinylene carbonate (1,3-dioxol-2-one), methyl vinylene carbonate (4-methyl-1,3-dioxol-2-one), and ethyl vinylene carbonate (4-ethyl). -1,3-dioxol-2-one), 4,5-dimethyl-1,3-dioxol-2-one, 4,5-diethyl-1,3-dioxol-2-one, 4-fluoro-1, Examples include 3-dioxol-2-one or 4-trifluoromethyl-1,3-dioxol-2-one, among which vinylene carbonate is preferable. This is because it is easily available and a high effect can be obtained.

  The cyclic carbonate having an unsaturated bond shown in Chemical formula 37 is a vinyl ethylene carbonate compound. Examples of the vinyl carbonate-based compound include vinyl ethylene carbonate (4-vinyl-1,3-dioxolan-2-one), 4-methyl-4-vinyl-1,3-dioxolan-2-one, and 4-ethyl. -4-vinyl-1,3-dioxolan-2-one, 4-n-propyl-4-vinyl-1,3-dioxolan-2-one, 5-methyl-4-vinyl-1,3-dioxolane-2 -One, 4,4-divinyl-1,3-dioxolan-2-one, 4,5-divinyl-1,3-dioxolan-2-one, and the like, among which vinyl ethylene carbonate is preferable. This is because it is easily available and a high effect can be obtained. Of course, as R23 to R26, all may be vinyl groups, all may be allyl groups, or vinyl groups and allyl groups may be mixed.

  The cyclic carbonate having an unsaturated bond shown in Chemical formula 38 is a methylene ethylene carbonate compound. Examples of the methylene ethylene carbonate compound include 4-methylene-1,3-dioxolan-2-one, 4,4-dimethyl-5-methylene-1,3-dioxolan-2-one, and 4,4-diethyl-5. -Methylene-1,3-dioxolan-2-one and the like. This methylene ethylene carbonate compound may have one methylene group (the compound shown in Chemical formula 38) or two methylene groups.

  The cyclic carbonate having an unsaturated bond may be catechol carbonate having a benzene ring in addition to those shown in Chemical Formulas 36 to 38.

  Moreover, it is preferable that the solvent contains sultone (cyclic sulfonic acid ester) or an acid anhydride. This is because the chemical stability of the electrolytic solution is further improved.

  Examples of the sultone include propane sultone and propene sultone. Among them, propene sultone is preferable. These may be single and multiple types may be mixed. The content of sultone in the solvent is, for example, 0.5% by weight or more and 5% by weight or less.

  Examples of the acid anhydride include carboxylic acid anhydrides such as succinic acid anhydride, glutaric acid anhydride and maleic acid anhydride, disulfonic acid anhydrides such as ethanedisulfonic acid anhydride and propanedisulfonic acid anhydride, sulfo Examples thereof include carboxylic acid and sulfonic acid anhydrides such as benzoic acid anhydride, sulfopropionic acid anhydride and sulfobutyric acid anhydride, among which succinic acid anhydride or sulfobenzoic acid anhydride is preferable. These may be single and multiple types may be mixed. The content of the acid anhydride in the solvent is, for example, 0.5% by weight or more and 5% by weight or less.

  The electrolyte salt contains, for example, one or more light metal salts such as a lithium salt. The series of electrolyte salts described below may be arbitrarily combined.

Examples of the lithium salt include lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium tetraphenylborate (LiB (C ₆ H ₅ ) ₄ ), methane Lithium sulfonate (LiCH ₃ SO ₃ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium tetrachloroaluminate (LiAlCl ₄ ), dilithium hexafluorosilicate (Li ₂ SiF ₆ ), lithium chloride (LiCl) ) Or lithium bromide (LiBr). This is because excellent electrical performance can be obtained in an electrochemical device.

  Among these, at least one selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium hexafluoroarsenate is preferable, and lithium hexafluorophosphate is more preferable. This is because a higher effect can be obtained because the internal resistance is lowered.

  In particular, the electrolyte salt preferably contains at least one selected from the group consisting of compounds represented by Chemical Formulas 39 to 41. This is because a higher effect can be obtained when used together with the above-described lithium hexafluorophosphate or the like. In addition, R31 and R33 in Chemical formula 39 may be the same or different. The same applies to R41 to R43 in Chemical Formula 40 and R51 and R52 in Chemical Formula 41.

（Ｘ３１は長周期型周期表における１族元素あるいは２族元素、またはアルミニウムである。Ｍ３１は遷移金属元素、または長周期型周期表における１３族元素、１４族元素あるいは１５族元素である。Ｒ３１はハロゲン基である。Ｙ３１は−（Ｏ＝）Ｃ−Ｒ３２−Ｃ（＝Ｏ）−、−（Ｏ＝）Ｃ−Ｃ（Ｒ３３）₂ −あるいは−（Ｏ＝）Ｃ−Ｃ（＝Ｏ）−である。ただし、Ｒ３２はアルキレン基、ハロゲン化アルキレン基、アリーレン基あるいはハロゲン化アリーレン基である。Ｒ３３はアルキル基、ハロゲン化アルキル基、アリール基あるいはハロゲン化アリール基である。なお、ａ３は１〜４の整数であり、ｂ３は０、２あるいは４であり、ｃ３、ｄ３、ｍ３およびｎ３は１〜３の整数である。）

(X31 is a group 1 element or group 2 element in the long-period periodic table, or aluminum. M31 is a transition metal element, or a group 13 element, group 14 element, or group 15 element in the long-period periodic table. R31 Y31 is — (O═) C—R32—C (═O) —, — (O═) C—C (R33) ₂ — or — (O═) C—C (═O) Where R32 is an alkylene group, a halogenated alkylene group, an arylene group or a halogenated arylene group, R33 is an alkyl group, a halogenated alkyl group, an aryl group or a halogenated aryl group, and a3 is (It is an integer of 1 to 4, b3 is 0, 2 or 4, and c3, d3, m3 and n3 are integers of 1 to 3.)

（Ｘ４１は長周期型周期表における１族元素あるいは２族元素である。Ｍ４１は遷移金属元素、または長周期型周期表における１３族元素、１４族元素あるいは１５族元素である。Ｙ４１は−（Ｏ＝）Ｃ−（Ｃ（Ｒ４１）₂ ）_b4−Ｃ（＝Ｏ）−、−（Ｒ４３）₂ Ｃ−（Ｃ（Ｒ４２）₂ ）_c4−Ｃ（＝Ｏ）−、−（Ｒ４３）₂ Ｃ−（Ｃ（Ｒ４２）₂ ）_c4−Ｃ（Ｒ４３）₂ −、−（Ｒ４３）₂ Ｃ−（Ｃ（Ｒ４２）₂ ）_c4−Ｓ（＝Ｏ）₂ −、−（Ｏ＝）₂ Ｓ−（Ｃ（Ｒ４２）₂ ）_d4−Ｓ（＝Ｏ）₂ −あるいは−（Ｏ＝）Ｃ−（Ｃ（Ｒ４２）₂ ）_d4−Ｓ（＝Ｏ）₂ −である。ただし、Ｒ４１およびＲ４３は水素基、アルキル基、ハロゲン基あるいはハロゲン化アルキル基であり、それぞれのうちの少なくとも１つはハロゲン基あるいはハロゲン化アルキル基である。Ｒ４２は水素基、アルキル基、ハロゲン基あるいはハロゲン化アルキル基である。なお、ａ４、ｅ４およびｎ４は１あるいは２であり、ｂ４およびｄ４は１〜４の整数であり、ｃ４は０〜４の整数であり、ｆ４およびｍ４は１〜３の整数である。）

(X41 is a group 1 element or group 2 element in the long periodic table. M41 is a transition metal element, or a group 13, element or group 15 element in the long period periodic table. Y41 is − ( O =) C- (C (R41 ) 2) b4 -C (= O) -, - (R43) 2 C- (C (R42) 2) c4 -C (= O) -, - (R43) 2 C -(C (R42) ₂ ) _c4 -C (R43) ₂ -,-(R43) ₂ C- (C (R42) ₂ ) _c4 -S (= O) ₂ -,-(O =) ₂ S- ( C (R42) ₂ ) _d4- S (= O) _2- or-(O =) C- (C (R42) ₂ ) _d4- S (= O) _2- where R41 and R43 are hydrogen groups. , An alkyl group, a halogen group or a halogenated alkyl group, at least one of each being a halogen group or a halogenated alkyl group. R42 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group, wherein a4, e4 and n4 are 1 or 2, b4 and d4 are integers of 1 to 4, and c4 Is an integer from 0 to 4, and f4 and m4 are integers from 1 to 3.)

（Ｘ５１は長周期型周期表における１族元素あるいは２族元素である。Ｍ５１は遷移金属元素、または長周期型周期表における１３族元素、１４族元素あるいは１５族元素である。Ｒｆはフッ素化アルキル基あるいはフッ素化アリール基であり、いずれの炭素数も１〜１０である。Ｙ５１は−（Ｏ＝）Ｃ−（Ｃ（Ｒ５１）₂ ）_d5−Ｃ（＝Ｏ）−、−（Ｒ５２）₂ Ｃ−（Ｃ（Ｒ５１）₂ ）_d5−Ｃ（＝Ｏ）−、−（Ｒ５２）₂ Ｃ−（Ｃ（Ｒ５１）₂ ）_d5−Ｃ（Ｒ５２）₂ −、−（Ｒ５２）₂ Ｃ−（Ｃ（Ｒ５１）₂ ）_d5−Ｓ（＝Ｏ）₂ −、−（Ｏ＝）₂ Ｓ−（Ｃ（Ｒ５１）₂ ）_e5−Ｓ（＝Ｏ）₂ −あるいは−（Ｏ＝）Ｃ−（Ｃ（Ｒ５１）₂ ）_e5−Ｓ（＝Ｏ）₂ −である。ただし、Ｒ５１は水素基、アルキル基、ハロゲン基あるいはハロゲン化アルキル基である。Ｒ５２は水素基、アルキル基、ハロゲン基あるいはハロゲン化アルキル基であり、そのうちの少なくとも１つはハロゲン基あるいはハロゲン化アルキル基である。なお、ａ５、ｆ５およびｎ５は１あるいは２であり、ｂ５、ｃ５およびｅ５は１〜４の整数であり、ｄ５は０〜４の整数であり、ｇ５およびｍ５は１〜３の整数である。）

(X51 is a group 1 element or group 2 element in the long-period periodic table. M51 is a transition metal element, or a group 13, element or group 15 element in the long-period periodic table. Rf is fluorinated. An alkyl group or a fluorinated aryl group, each having 1 to 10 carbon atoms Y51 is — (O═) C— (C (R51) ₂ ) _d5 —C (═O) —, — (R52); ₂ C- (C (R51) ₂ ) _d5 -C (= O)-,-(R52) ₂ C- (C (R51) ₂ ) _d5 -C (R52) ₂ -,-(R52) ₂ C- ( _{C (R51) 2) d5 -S} (= O) 2 -, - (O =) 2 S- (C (R51) 2) e5 -S (= O) 2 - or - (O =) C- (C _{(R51) 2) e5 -S (} = O) 2 -. is, however, R51 is a hydrogen group, an alkyl group, a halogen group, or a halogen Kaa R52 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group, at least one of which is a halogen group or a halogenated alkyl group, wherein a5, f5 and n5 are 1 or 2; B5, c5 and e5 are integers of 1 to 4, d5 is an integer of 0 to 4, and g5 and m5 are integers of 1 to 3.)

  The long-period periodic table is represented by a revised inorganic chemical nomenclature proposed by IUPAC (International Pure and Applied Chemistry Association). Specifically, group 1 elements are hydrogen, lithium, sodium, potassium, rubidium, cesium and francium. Group 2 elements are beryllium, magnesium, calcium, strontium, barium and radium. Group 13 elements are boron, aluminum, gallium, indium and thallium. Group 14 elements are carbon, silicon, germanium, tin and lead. Group 15 elements are nitrogen, phosphorus, arsenic, antimony and bismuth.

  Examples of the compound represented by Chemical formula 39 include the compounds represented by Chemical formulas (1) to (6). Examples of the compound represented by Chemical Formula 40 include compounds represented by Chemical Formulas (1) to (8). Examples of the compound represented by Chemical formula 41 include the compound represented by Chemical formula 44. Needless to say, the compound having the structure shown in Chemical formula 39 to Chemical formula 41 is not limited to the compound shown in Chemical formula 42 to Chemical formula 44.

  Moreover, the electrolyte salt may contain at least one selected from the group consisting of compounds represented by Chemical Formulas 45 to 47. This is because a higher effect can be obtained when used together with the above-described lithium hexafluorophosphate or the like. Note that m and n in Chemical formula 45 may be the same or different. The same applies to p, q and r in Chemical formula 47.

（ｍおよびｎは１以上の整数である。）

(M and n are integers of 1 or more.)

（Ｒ６１は炭素数が２以上４以下の直鎖状あるいは分岐状のパーフルオロアルキレン基である。）

(R61 is a linear or branched perfluoroalkylene group having 2 to 4 carbon atoms.)

（ｐ、ｑおよびｒは１以上の整数である。）

(P, q and r are integers of 1 or more.)

Examples of the chain compound shown in Chemical Formula 45 include bis (trifluoromethanesulfonyl) imide lithium (LiN (CF ₃ SO ₂ ) ₂ ), bis (pentafluoroethanesulfonyl) imide lithium (LiN (C ₂ F ₅ SO ₂ ) ₂ ), (trifluoromethanesulfonyl) (pentafluoroethanesulfonyl) imide lithium (LiN (CF ₃ SO ₂ ) (C ₂ F ₅ SO ₂ )), (trifluoromethanesulfonyl) (heptafluoropropanesulfonyl) imide lithium ( LiN (CF ₃ SO ₂ ) (C ₃ F ₇ SO ₂ )) or (trifluoromethanesulfonyl) (nonafluorobutanesulfonyl) imidolithium (LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ )) Can be mentioned. These may be single and multiple types may be mixed.

  Examples of the cyclic compound represented by Chemical Formula 46 include a series of compounds represented by Chemical Formula 48. That is, (1) 1,2-perfluoroethanedisulfonylimide lithium shown in Chemical formula 48, (2) 1,3-perfluoropropane disulfonylimide lithium, (3) 1,3-perfluorobutane Disulfonylimide lithium, 1,4-perfluorobutane disulfonylimide lithium of (4), and the like. These may be single and multiple types may be mixed. Among these, 1,2-perfluoroethanedisulfonylimide lithium is preferable. This is because a high effect can be obtained.

Examples of the chain compound shown in Chemical formula 47 include lithium tris (trifluoromethanesulfonyl) methide (LiC (CF ₃ SO ₂ ) ₃ ).

  The content of the electrolyte salt is preferably 0.3 mol / kg or more and 3.0 mol / kg or less with respect to the solvent. This is because, outside this range, the ion conductivity may be extremely lowered.

  According to this electrolytic solution, since the solvent contains the nitrile compound shown in Chemical Formula 3, compared with the case of not containing the nitrile compound or the case of containing another nitrile compound, Stability is improved. More specifically, the nitrile compound shown in Chemical Formula 3 has a site where the nitrile group and the electron withdrawing group (X) are directly bonded. For this reason, for example, as represented by Chemical Formula 49 or Chemical Formula 50, the nitrile group only has a nitrile group and does not have an electron-withdrawing group. It becomes easy to suppress decomposition | disassembly of a solvent etc. Therefore, since the decomposition reaction of the electrolytic solution is suppressed during the electrode reaction, it can contribute to the improvement of the cycle characteristics and storage characteristics of the electrochemical device. In this case, when the content of the nitrile compound in the solvent is 0.01 wt% or more and 10 wt% or less, a high effect can be obtained.

  In particular, if the nitrile compound shown in Chemical Formula 3 is a compound shown in Chemical Formulas 4 to 6, a high effect can be obtained. In this case, R1 in Chemical Formula 4 is an alkyl group having 1 to 10 carbon atoms, an aryl group, a halogenated alkyl group having 1 to 10 carbon atoms, a halogenated aryl group, or a derivative thereof. If R2 in the alkylene group is an alkylene group or halogenated alkylene group having 1 to 3 carbon atoms, higher effects can be obtained.

  Further, the solvent has at least one of a chain carbonate having a halogen shown in Chemical formula 32 and a cyclic carbonate having a halogen shown in Chemical formula 33, or an unsaturated bond shown in Chemical formulas 36 to 38. If at least one of cyclic carbonates, sultone, or acid anhydride is contained, higher effects can be obtained.

  In addition, the electrolyte salt is at least one selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium hexafluoroarsenate. A higher effect can be obtained if at least one of the group consisting of compounds or at least one of the group consisting of compounds shown in Chemical formulas 45 to 47 is contained.

  Next, usage examples of the above-described electrolytic solution will be described. Here, taking a secondary battery as an example of an electrochemical device, the above-described electrolytic solution is used as follows.

(First secondary battery)
1 and 2 show a cross-sectional configuration of the first secondary battery, and FIG. 2 shows an enlarged part of the spirally wound electrode body 20 shown in FIG. The secondary battery described here is, for example, a lithium ion secondary battery in which the capacity of the negative electrode 22 is expressed based on insertion and extraction of lithium as an electrode reactant.

  This secondary battery mainly includes a wound electrode body 20 in which a positive electrode 21 and a negative electrode 22 are laminated and wound through a separator 23 inside a substantially hollow cylindrical battery can 11 and a pair of insulating plates. 12 and 13 are accommodated. The battery structure using the cylindrical battery can 11 is called a cylindrical type.

  The battery can 11 has, for example, a hollow structure in which one end is closed and the other end is opened, and is made of a metal material such as iron, aluminum, or an alloy thereof. In addition, when the battery can 11 is comprised with iron, plating, such as nickel, may be given, for example. The pair of insulating plates 12 and 13 are arranged so as to sandwich the wound electrode body 20 from above and below and to extend perpendicularly to the wound peripheral surface.

  A battery lid 14 and a safety valve mechanism 15 and a heat sensitive resistance element (Positive Temperature Coefficient: PTC element) 16 provided inside the battery can 11 are caulked through a gasket 17 at the open end of the battery can 11. It is attached. Thereby, the inside of the battery can 11 is sealed. The battery lid 14 is made of a metal material similar to that of the battery can 11, for example. The safety valve mechanism 15 is electrically connected to the battery lid 14 via the heat sensitive resistance element 16. In the safety valve mechanism 15, when the internal pressure becomes a certain level or more due to an internal short circuit or external heating, the disk plate 15 </ b> A is reversed and the electric power between the battery lid 14 and the wound electrode body 20 is reversed. Connection is cut off. The heat-sensitive resistor element 16 is configured to prevent abnormal heat generation caused by a large current by limiting the current by increasing the resistance in response to a rise in temperature. The gasket 17 is made of, for example, an insulating material, and asphalt is applied to the surface thereof.

  A center pin 24 may be inserted in the center of the wound electrode body 20. In this wound electrode body 20, a positive electrode lead 25 made of a metal material such as aluminum is connected to the positive electrode 21, and a negative electrode lead 26 made of a metal material such as nickel is connected to the negative electrode 22. . The positive electrode lead 25 is welded to the safety valve mechanism 15 and electrically connected to the battery lid 14, and the negative electrode lead 26 is welded to the battery can 11 and electrically connected thereto.

  For example, the positive electrode 21 is obtained by providing a positive electrode active material layer 21B on both surfaces of a positive electrode current collector 21A having a pair of surfaces. However, the positive electrode active material layer 21B may be provided only on one surface of the positive electrode current collector 21A.

  The positive electrode current collector 21A is made of a metal material such as aluminum, nickel, or stainless steel, for example.

  The positive electrode active material layer 21B includes one or more positive electrode materials capable of inserting and extracting lithium as a positive electrode active material, and a positive electrode binder or a positive electrode conductive material as necessary. Other materials such as agents may be included.

As a positive electrode material capable of inserting and extracting lithium, for example, a lithium-containing compound is preferable. This is because a high energy density can be obtained. Examples of the lithium-containing compound include a composite oxide containing lithium and a transition metal element, and a phosphate compound containing lithium and a transition metal element. Especially, what contains at least 1 sort (s) of the group which consists of cobalt, nickel, manganese, and iron as a transition metal element is preferable. This is because a higher voltage can be obtained. The chemical formula is represented by, for example, Li _x M1O ₂ or Li _y M2PO ₄ . In the formula, M1 and M2 represent one or more transition metal elements. The values of x and y vary depending on the charge / discharge state, and are generally 0.05 ≦ x ≦ 1.10 and 0.05 ≦ y ≦ 1.10.

Examples of the composite oxide containing lithium and a transition metal element include lithium cobalt composite oxide (Li _x CoO ₂ ), lithium nickel composite oxide (Li _x NiO ₂ ), and lithium nickel cobalt composite oxide (Li _x Ni). _1-z Co _z O ₂ (z <1)), lithium nickel cobalt manganese composite oxide (Li _x Ni _(1-vw) Co _v Mn _w O ₂ (v + w <1)), or lithium having a spinel structure Manganese composite oxide (LiMn ₂ O ₄ ) and the like can be mentioned. Among these, a complex oxide containing cobalt is preferable. This is because a high capacity can be obtained and excellent cycle characteristics can be obtained. Examples of the phosphate compound containing lithium and a transition metal element include a lithium iron phosphate compound (LiFePO ₄ ) or a lithium iron manganese phosphate compound (LiFe _1-u Mn _u PO ₄ (u <1)). Is mentioned.

  In addition, examples of the positive electrode material capable of inserting and extracting lithium include oxides such as titanium oxide, vanadium oxide and manganese dioxide, disulfides such as titanium disulfide and molybdenum sulfide, and niobium selenide. And chalcogenides such as sulfur, polyaniline and polythiophene, and other conductive polymers.

  Of course, the positive electrode material capable of inserting and extracting lithium may be other than the above. Further, two or more kinds of the series of positive electrode materials described above may be mixed in any combination.

  Examples of the positive electrode binder include synthetic rubbers such as styrene butadiene rubber, fluorine rubber, and ethylene propylene diene, and polymer materials such as polyvinylidene fluoride. These may be single and multiple types may be mixed.

  Examples of the positive electrode conductive agent include carbon materials such as graphite, carbon black, acetylene black, and ketjen black. These may be single and multiple types may be mixed. The positive electrode conductive agent may be a metal material or a conductive polymer as long as it is a conductive material.

  In the negative electrode 22, for example, a negative electrode active material layer 22B is provided on both surfaces of a negative electrode current collector 22A having a pair of surfaces. However, the negative electrode active material layer 22B may be provided only on one surface of the negative electrode current collector 22A.

  The anode current collector 22A is made of, for example, a metal material such as copper, nickel, or stainless steel. The surface of the anode current collector 22A is preferably roughened. This is because the so-called anchor effect improves the adhesion between the negative electrode current collector 22A and the negative electrode active material layer 22B. In this case, the surface of the negative electrode current collector 22A only needs to be roughened at least in a region facing the negative electrode active material layer 22B. Examples of the roughening method include a method of forming fine particles by electrolytic treatment. This electrolytic treatment is a method of forming irregularities by forming fine particles on the surface of the anode current collector 22A by an electrolytic method in an electrolytic bath. The copper foil produced using the electrolytic method is generally called “electrolytic copper foil”.

  The negative electrode active material layer 22B includes one or more negative electrode materials capable of inserting and extracting lithium as a negative electrode active material, and a negative electrode binder or a negative electrode conductive material as necessary. Other materials such as agents may be included. At this time, the chargeable capacity of the negative electrode material capable of inserting and extracting lithium is preferably larger than the discharge capacity of the positive electrode. Note that details regarding the negative electrode binder and the negative electrode conductive agent are the same as, for example, the positive electrode binder and the positive electrode conductive agent, respectively.

  Examples of the negative electrode material capable of inserting and extracting lithium include materials capable of inserting and extracting lithium and having at least one of a metal element and a metalloid element as a constituent element. . This is because a high energy density can be obtained. Such a negative electrode material may be a single element or an alloy or a compound of a metal element or a metalloid element, and may have one or two or more phases thereof at least in part. The “alloy” in the present invention includes an alloy containing one or more metal elements and one or more metalloid elements in addition to an alloy composed of two or more metal elements. Further, the “alloy” may contain a nonmetallic element. This structure includes a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or a material in which two or more of them coexist.

  Examples of the metal element or metalloid element described above include a metal element or metalloid element capable of forming an alloy with lithium. Specifically, magnesium, boron (B), aluminum, gallium (Ga), indium (In), silicon, germanium (Ge), tin, lead (Pb), bismuth (Bi), cadmium (Cd), silver ( Ag), zinc, hafnium (Hf), zirconium (Zr), yttrium (Y), palladium (Pd) or platinum (Pt). Among these, at least one of silicon and tin is preferable, and silicon is more preferable. This is because a high energy density can be obtained because the ability to occlude and release lithium is large.

  Examples of the material having at least one of silicon and tin include, for example, a simple substance, an alloy or a compound of silicon, a simple substance, an alloy or a compound of tin, or one or two or more phases thereof. The material which has is mentioned.

Examples of the silicon alloy include, as the second constituent element other than silicon, tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony (Sb), and chromium. Those having at least one of the groups are mentioned. Examples of the silicon compound include those having oxygen or carbon (C), and may contain the second constituent element described above in addition to silicon. Examples of silicon alloys or compounds include SiB ₄ , SiB ₆ , Mg ₂ Si, Ni ₂ Si, TiSi ₂ , MoSi ₂ , CoSi ₂ , NiSi ₂ , CaSi ₂ , CrSi ₂ , Cu ₅ Si, FeSi ₂ , MnSi. ₂ , NbSi ₂ , TaSi ₂ , VSi ₂ , WSi ₂ , ZnSi ₂ , SiC, Si ₃ N ₄ , Si ₂ N ₂ O, SiO _v (0 <v ≦ 2), SnO _w (0 <w ≦ 2), Or LiSiO etc. are mentioned.

As an alloy of tin, for example, as a second constituent element other than tin, among the group consisting of silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony and chromium The thing which has at least 1 sort (s) of these is mentioned. Examples of the tin compound include those having oxygen or carbon, and may contain the above-described second constituent element in addition to tin. Examples of tin alloys or compounds include SnSiO ₃ , LiSnO, or Mg ₂ Sn.

  In particular, as a material having at least one of silicon and tin, for example, a material having tin as the first constituent element and second and third constituent elements in addition to it is preferable. The second constituent elements are cobalt, iron, magnesium, titanium, vanadium (V), chromium, manganese, nickel, copper, zinc, gallium, zirconium, niobium (Nb), molybdenum, silver, indium, cerium (Ce), It is at least one selected from the group consisting of hafnium, tantalum (Ta), tungsten (W), bismuth and silicon. The third constituent element is at least one selected from the group consisting of boron, carbon, aluminum, and phosphorus (P). This is because having the second and third constituent elements improves the cycle characteristics.

  Among them, tin, cobalt and carbon are included as constituent elements, the carbon content is 9.9 mass% or more and 29.7 mass% or less, and the ratio of cobalt to the total of tin and cobalt (Co / (Sn + Co)) is 30. An SnCoC-containing material having a mass% of 70% by mass or less is preferable. This is because a high energy density can be obtained in such a composition range.

  This SnCoC-containing material may further contain other constituent elements as necessary. As other constituent elements, for example, silicon, iron, nickel, chromium, indium, niobium, germanium, titanium, molybdenum, aluminum, phosphorus, gallium, bismuth, and the like are preferable, and two or more of them may be included. . This is because a higher effect can be obtained.

  The SnCoC-containing material has a phase containing tin, cobalt, and carbon, and the phase is preferably a low crystalline or amorphous phase. This phase is a reaction phase capable of reacting with lithium, whereby excellent cycle characteristics can be obtained. The half-value width of the diffraction peak obtained by X-ray diffraction of this phase is 1.0 ° or more at a diffraction angle 2θ when CuKα ray is used as the specific X-ray and the drawing speed is 1 ° / min. Is preferred. This is because lithium is occluded and released more smoothly and the reactivity with the electrolyte is reduced.

  Whether or not the diffraction peak obtained by X-ray diffraction corresponds to a reaction phase capable of reacting with lithium can be easily determined by comparing X-ray diffraction charts before and after electrochemical reaction with lithium. can do. For example, if the position of the diffraction peak changes before and after the electrochemical reaction with lithium, it corresponds to a reaction phase capable of reacting with lithium. In this case, for example, a diffraction peak of a low crystalline or amorphous reaction phase is observed between 2θ = 20 ° and 50 °. This low crystalline or amorphous reaction phase contains, for example, each of the above-described constituent elements, and is considered to be mainly low-crystallized or amorphous due to carbon.

  Note that the SnCoC-containing material may have a phase containing a simple substance or a part of each constituent element in addition to a low crystalline or amorphous phase.

  In particular, in the SnCoC-containing material, it is preferable that at least a part of carbon as a constituent element is bonded to a metal element or a metalloid element as another constituent element. This is because aggregation or crystallization of tin or the like is suppressed.

  As a measuring method for examining the bonding state of elements, for example, X-ray photoelectron spectroscopy (XPS) can be cited. This XPS irradiates the sample surface with soft X-rays (Al-Kα ray or Mg-Kα ray is used in a commercial apparatus), and measures the kinetic energy of photoelectrons jumping out of the sample surface. To elemental composition in the region of several nanometers and the bonding state of the elements.

  The binding energy of the core orbital electrons of the element changes in a first approximation in correlation with the charge density on the element. For example, when the charge density of the carbon element decreases due to an interaction with an element present in the vicinity, the outer electrons such as 2p electrons decrease, so the 1s electron of the carbon element exerts a strong binding force from the shell. Will receive. That is, the binding energy increases as the charge density of the element decreases. In XPS, when the binding energy increases, the peak shifts to a high energy region.

  In XPS, if the peak of carbon 1s orbital (C1s) is graphite, it appears at 284.5 eV in an energy calibrated apparatus so that the peak of 4f orbital (Au4f) of gold atom is obtained at 84.0 eV. . Moreover, if it is surface contamination carbon, it will appear at 284.8 eV. On the other hand, when the charge density of the carbon element is high, for example, when it is bonded to an element more positive than carbon, the C1s peak appears in a region lower than 284.5 eV. That is, when at least a part of the carbon contained in the SnCoC-containing material is bonded to another constituent element such as a metal element or a metalloid element, the peak of the synthetic wave of C1s obtained for the SnCoC-containing material is 284. Appears in the region lower than 5 eV.

  When performing XPS measurement, it is preferable that the surface is lightly sputtered with an argon ion gun attached to the XPS apparatus when the surface is covered with surface-contaminated carbon. When the SnCoC-containing material to be measured is present in the negative electrode 22, the secondary battery is disassembled and the negative electrode 22 is taken out and then washed with a volatile solvent such as dimethyl carbonate. This is to remove the low-volatile solvent and the electrolyte salt present on the surface of the negative electrode 22. These samplings are desirably performed in an inert atmosphere.

  In XPS measurement, for example, the peak of C1s is used to correct the energy axis of the spectrum. Usually, since surface-contaminated carbon exists on the surface of the substance, the C1s peak of the surface-contaminated carbon is set to 284.8 eV, which is used as an energy standard. In XPS measurement, the waveform of the peak of C1s is obtained as a form including the surface contamination carbon peak and the carbon peak in the SnCoC-containing material. For example, by analyzing using commercially available software, The surface contamination carbon peak is separated from the carbon peak in the SnCoC-containing material. In the waveform analysis, the position of the main peak existing on the lowest bound energy side is used as the energy reference (284.8 eV).

  This SnCoC-containing material can be formed, for example, by melting a mixture of raw materials of each constituent element in an electric furnace, a high-frequency induction furnace, an arc melting furnace or the like and then solidifying the mixture. Also, various atomizing methods such as gas atomization or water atomization, methods using various mechanochemical reactions such as various roll methods, mechanical alloying methods, and mechanical milling methods may be used. Among these, a method using a mechanochemical reaction is preferable. This is because the SnCoC-containing material has a low crystalline or amorphous structure. In the method using the mechanochemical reaction, for example, a manufacturing apparatus such as a planetary ball mill apparatus or an attritor can be used.

  The raw material may be a mixture of individual constituent elements, but it is preferable to use an alloy for some of the constituent elements other than carbon. This is because, by adding carbon to such an alloy and synthesizing it by a method using the mechanical alloying method, a low crystallization or amorphous structure can be obtained, and the reaction time can be shortened. The raw material may be in the form of powder or a block.

  In addition to this SnCoC-containing material, an SnCoFeC-containing material having tin, cobalt, iron and carbon as constituent elements is also preferable. The composition of the SnCoFeC-containing material can be arbitrarily set. For example, as a composition when the iron content is set to be small, the carbon content is 9.9 mass% or more and 29.7 mass% or less, and the iron content is 0.3 mass% or more and 5.9 mass%. %, And the ratio of cobalt to the total of tin and cobalt (Co / (Sn + Co)) is preferably 30% by mass or more and 70% by mass or less. In addition, for example, as a composition when the content of iron is set to be large, the content of carbon is 11.9 mass% or more and 29.7 mass% or less, and cobalt and iron with respect to the total of tin, cobalt, and iron The total ratio of (Co + Fe) / (Sn + Co + Fe)) is 26.4 mass% to 48.5 mass%, and the ratio of cobalt to the total of cobalt and iron (Co / (Co + Fe)) is 9.9 mass% It is preferable that it is 79.5 mass% or more. This is because a high energy density can be obtained in such a composition range. The crystallinity of the SnCoFeC-containing material, the method for measuring the bonding state of elements, the formation method, and the like are the same as those of the above-described SnCoC-containing material.

  As a material capable of inserting and extracting lithium, a simple substance, an alloy or a compound of silicon, a simple substance, an alloy or a compound of tin, or a material having one or more phases thereof at least in part is used. The negative electrode active material layer 22B is formed using, for example, a vapor phase method, a liquid phase method, a thermal spraying method, a coating method or a firing method, or two or more of these methods. In this case, it is preferable that the anode current collector 22A and the anode active material layer 22B are alloyed at least at a part of the interface. Specifically, the constituent element of the negative electrode current collector 22A may be diffused into the negative electrode active material layer 22B at the interface between them, or the constituent element of the negative electrode active material layer 22B is diffused into the negative electrode current collector 22A. These constituent elements may be diffused with each other. This is because breakage due to expansion and contraction of the negative electrode active material layer 22B during charging and discharging is suppressed, and electron conductivity between the negative electrode current collector 22A and the negative electrode active material layer 22B is improved.

  As the vapor phase method, for example, physical deposition method or chemical deposition method, specifically, vacuum deposition method, sputtering method, ion plating method, laser ablation method, thermal chemical vapor deposition (CVD) Or plasma chemical vapor deposition. As the liquid phase method, a known method such as electrolytic plating or electroless plating can be used. The application method is, for example, a method in which a particulate negative electrode active material is mixed with a binder and then dispersed in a solvent and applied. The baking method is, for example, a method in which a heat treatment is performed at a temperature higher than the melting point of a binder or the like after being applied by a coating method. Regarding the firing method, a known method can be used, and examples thereof include an atmosphere firing method, a reaction firing method, and a hot press firing method.

  In addition to the above, examples of the material capable of inserting and extracting lithium include a carbon material. Examples of the carbon material include graphitizable carbon, non-graphitizable carbon having a (002) plane spacing of 0.37 nm or more, and graphite having a (002) plane spacing of 0.34 nm or less. It is. More specifically, there are pyrolytic carbons, cokes, glassy carbon fibers, organic polymer compound fired bodies, activated carbon or carbon blacks. Of these, the cokes include pitch coke, needle coke, petroleum coke, and the like. The organic polymer compound fired body is obtained by firing and carbonizing a phenol resin, a furan resin, or the like at an appropriate temperature. The carbon material is preferable because the change in crystal structure associated with insertion and extraction of lithium is very small, so that a high energy density can be obtained, and excellent cycle characteristics can be obtained. The shape of the carbon material may be any of fibrous, spherical, granular or scale-like.

  In addition, examples of a material capable of inserting and extracting lithium include metal oxides and polymer compounds that can store and release lithium. Examples of the metal oxide include iron oxide, ruthenium oxide, and molybdenum oxide. Examples of the polymer compound include polyacetylene, polyaniline, and polypyrrole.

  Of course, materials other than those described above may be used as materials capable of inserting and extracting lithium. Moreover, two or more kinds of the series of negative electrode materials described above may be mixed in any combination.

  The negative electrode active material described above has a plurality of particles. That is, the negative electrode active material layer 22B has a plurality of particulate negative electrode active materials (hereinafter simply referred to as “negative electrode active material particles”). It is formed by. However, the negative electrode active material particles may be formed by a method other than the gas phase method.

  When the negative electrode active material particles are formed by a deposition method such as a vapor phase method, the negative electrode active material particles may have a single layer structure formed through a single deposition step, or may be a plurality of times. It may have a multilayer structure formed through the deposition process. However, when the negative electrode active material particles are formed by a vapor deposition method that involves high heat during deposition, the negative electrode active material particles preferably have a multilayer structure. By performing the deposition process of the negative electrode material in a plurality of times (the negative electrode material is sequentially formed and deposited thinly), the negative electrode current collector 22A is exposed to high heat compared to the case where the deposition process is performed once. This is because the time required for heat treatment is shortened and it is difficult to receive thermal damage.

  For example, the negative electrode active material particles are preferably grown from the surface of the negative electrode current collector 22A in the thickness direction of the negative electrode active material layer 22B, and are connected to the negative electrode current collector 22A at the root. This is because the expansion and contraction of the negative electrode active material layer 22B are suppressed during charging and discharging. In this case, the negative electrode active material particles are formed by a vapor phase method or the like, and as described above, it is preferable that the negative electrode active material particles are alloyed at least at a part of the interface with the negative electrode current collector 22A. Specifically, the constituent element of the negative electrode current collector 22A may be diffused into the negative electrode active material particles at the interface between them, or the constituent element of the negative electrode active material particles may be diffused into the negative electrode current collector 22A. Alternatively, both constituent elements may be diffused with each other.

  In particular, the negative electrode active material layer 22B has an oxide-containing film that covers the surface of the negative electrode active material particles (a region that will be in contact with the electrolyte solution if no oxide-containing film is provided), if necessary. It is preferable. This is because the oxide-containing film functions as a protective film against the electrolytic solution, and the decomposition reaction of the electrolytic solution is suppressed during charging and discharging, so that the cycle characteristics and the storage characteristics are improved. The oxide-containing film may cover the entire surface of the negative electrode active material particles, or may cover only a part of the surface, but it is preferable to cover the entire surface. This is because the decomposition reaction of the electrolytic solution is effectively suppressed.

  This oxide-containing film contains, for example, at least one oxide selected from the group consisting of silicon, germanium, and tin, and among these, it is preferable to contain an oxide of silicon. This is because the entire surface of the negative electrode active material particles can be easily covered and an excellent protective action can be obtained. Of course, the oxide-containing film may contain an oxide other than the above.

  The oxide-containing film is formed by, for example, a gas phase method or a liquid phase method, and among these, it is preferable that the oxide-containing film is formed by a liquid phase method. This is because the surface of the negative electrode active material particles can be easily covered over a wide range. Examples of the liquid phase method include a liquid phase precipitation method, a sol-gel method, a coating method, a dip coating method, and the like. Among these, a liquid phase precipitation method, a sol-gel method, or a dip coating method is preferable, and a liquid phase precipitation method is more preferable. This is because a higher effect can be obtained. Note that the oxide-containing film may be formed by a single forming method among the above-described series of forming methods, or may be formed by two or more forming methods.

  Further, the negative electrode active material layer 22B is a metal material that does not alloy with lithium in gaps in the negative electrode active material layer 22B, that is, gaps between negative electrode active material particles described later or gaps in the negative electrode active material particles as necessary. It is preferable to have. Since a plurality of negative electrode active material particles are bound via a metal material and the expansion and contraction of the negative electrode active material layer 22B are suppressed by the presence of the metal material in the gaps described above, cycle characteristics and storage characteristics are improved. It is because it improves.

  This metal material has, for example, a metal element that does not alloy with lithium as a constituent element. Examples of such a metal element include at least one selected from the group consisting of iron, cobalt, nickel, zinc, and copper, and among these, cobalt is preferable. This is because the metal material can easily enter the gap, and an excellent binding action can be obtained. Of course, the metal material may have a metal element other than the above. However, the “metal material” mentioned here is not limited to a simple substance, but is a broad concept that includes alloys and metal compounds.

  The metal material is formed by, for example, a gas phase method or a liquid phase method, and among these, it is preferably formed by a liquid phase method. This is because the metal material easily enters the gap in the negative electrode active material layer 22B. Examples of the liquid phase method include an electrolytic plating method and an electroless plating method, among which the electrolytic plating method is preferable. This is because the metal material is more likely to enter the gaps and the formation time thereof can be shortened. In addition, the metal material may be formed by a single forming method among the above-described series of forming methods, or may be formed by two or more kinds of forming methods.

  Note that the negative electrode active material layer 22B may include only one of the oxide-containing film or the metal material described above, or may include both. However, in order to further improve the cycle characteristics and the storage characteristics, it is preferable to have both. In addition, in the case of having only one of them, it is preferable to have an oxide-containing film in order to further improve cycle characteristics and storage characteristics. In the case where both the oxide-containing film and the metal material are included, whichever may be formed first, in order to further improve cycle characteristics and storage characteristics, the oxide-containing film is formed first. Is preferred.

  Here, the detailed configuration of the negative electrode 22 will be described with reference to FIGS.

  First, the case where the negative electrode active material layer 22B has an oxide-containing film together with a plurality of negative electrode active material particles will be described. FIG. 3 schematically shows a cross-sectional structure of the negative electrode 22 of the present invention, and FIG. 4 schematically shows a cross-sectional structure of the negative electrode of the reference example. 3 and 4 show a case where the negative electrode active material particles have a single layer structure.

  In the negative electrode of the present invention, as shown in FIG. 3, for example, when a negative electrode material is deposited on the negative electrode current collector 22A by a vapor phase method such as a vapor deposition method, a plurality of negative electrodes are formed on the negative electrode current collector 22A. Active material particles 221 are formed. In this case, when the surface of the negative electrode current collector 22A is roughened and a plurality of protrusions (for example, fine particles formed by electrolytic treatment) are present on the surface, the negative electrode active material particles 221 are arranged together with the protrusions described above. In order to grow in the thickness direction, a plurality of negative electrode active material particles 221 are arranged on the negative electrode current collector 22A and connected to the surface of the negative electrode current collector 22A at the root. After that, for example, when the oxide-containing film 222 is formed on the surface of the negative electrode active material particle 221 by a liquid phase method such as a liquid phase precipitation method, the oxide-containing film 222 substantially covers the surface of the negative electrode active material particle 221. The entire surface is covered, and in particular, a wide range from the top to the root of the negative electrode active material particles 221 is covered. This wide covering state by the oxide-containing film 222 is a characteristic obtained when the oxide-containing film 222 is formed by a liquid phase method. That is, when the oxide-containing film 222 is formed by using the liquid phase method, the covering action extends not only to the top of the negative electrode active material particles 221 but also to the root, so that the base is covered with the oxide-containing film 222. .

  On the other hand, in the negative electrode of the reference example, as shown in FIG. 4, for example, after the plurality of negative electrode active material particles 221 are formed by the vapor phase method, the oxide-containing film 223 is similarly formed by the vapor phase method. When formed, the oxide-containing film 223 covers only the tops of the negative electrode active material particles 221. This narrow-range covering state by the oxide-containing film 223 is a characteristic obtained when the oxide-containing film 223 is formed by a vapor phase method. That is, when the oxide-containing film 223 is formed by using the vapor phase method, the covering action does not reach the root of the negative electrode active material particle 221, so that the base is not covered by the oxide-containing film 223. .

  Although FIG. 3 illustrates the case where the negative electrode active material layer 22B is formed by a vapor phase method, the negative electrode active material layer 22B may be formed by another forming method such as a coating method or a sintering method. Similarly, the oxide-containing film is formed so as to cover almost the entire surface of the plurality of negative electrode active material particles.

  Next, the case where the negative electrode active material layer 22B includes a metal material that does not alloy with lithium together with the plurality of negative electrode active material particles will be described. FIG. 5 shows an enlarged cross-sectional structure of the negative electrode 22, (A) is a scanning electron microscope (SEM) photograph (secondary electron image), and (B) is an SEM shown in (A). It is a schematic picture of the statue. FIG. 5 shows a case where a plurality of negative electrode active material particles 221 have a multilayer structure in the particles.

  When the negative electrode active material particles 221 have a multilayer structure, a plurality of gaps 224 are generated in the negative electrode active material layer 22B due to the arrangement structure, multilayer structure, and surface structure of the plurality of negative electrode active material particles 221. Yes. The gap 224 mainly includes two types of gaps 224A and 224B classified according to the cause of occurrence. The gap 224 </ b> A is generated between adjacent negative electrode active material particles 221, and the gap 224 </ b> B is generated between layers in the negative electrode active material particles 221.

  Note that a void 225 may be formed on the exposed surface (outermost surface) of the negative electrode active material particles 221. The void 225 is generated between the protrusions as a whisker-like fine protrusion (not shown) is formed on the surface of the negative electrode active material particle 221. The void 225 may be generated over the entire exposed surface of the negative electrode active material particles 221 or may be generated only in part. However, since the above-described whisker-like protrusions are generated on the surface every time the negative electrode active material particles 221 are formed, the void 225 is generated not only on the exposed surface of the negative electrode active material particles 221 but also between the layers. There is.

  FIG. 6 shows another cross-sectional structure of the negative electrode 22 and corresponds to FIG. The negative electrode active material layer 22B has a metal material 226 that does not alloy with lithium in the gaps 224A and 224B. In this case, only one of the gaps 224A and 224B may have the metal material 226, but it is preferable that both have the metal material 226. This is because a higher effect can be obtained.

  The metal material 226 enters the gap 224A between the adjacent negative electrode active material particles 221. Specifically, when the negative electrode active material particles 221 are formed by a vapor phase method or the like, as described above, the negative electrode active material particles 221 grow for each protrusion existing on the surface of the negative electrode current collector 22A. A gap 224 </ b> A is generated between the adjacent negative electrode active material particles 221. Since the gap 224A causes a decrease in the binding property of the negative electrode active material layer 22B, the above-described gap 224A is filled with the metal material 226 in order to improve the binding property. In this case, it is sufficient that a part of the gap 224A is filled, but a larger filling amount is preferable. This is because the binding property of the negative electrode active material layer 22B is further improved. The filling amount of the metal material 226 is preferably 20% or more, more preferably 40% or more, and further preferably 80% or more.

  In addition, the metal material 226 enters the gap 224 </ b> B in the negative electrode active material particles 221. Specifically, when the negative electrode active material particles 221 have a multilayer structure, a gap 224B is generated between the layers. The gap 224B, like the gap 224A, causes a decrease in the binding property of the negative electrode active material layer 22B. Therefore, in order to increase the binding property, the gap 224B is filled with the metal material 226. ing. In this case, it is sufficient that a part of the gap 224B is filled, but a larger filling amount is preferable. This is because the binding property of the negative electrode active material layer 22B is further improved.

  Note that the negative electrode active material layer 22B is provided in order to prevent negative whisker-like protrusions (not shown) generated on the exposed surface of the uppermost negative electrode active material particles 221 from adversely affecting the performance of the secondary battery. A metal material 226 may be provided in the gap 225. Specifically, when the negative electrode active material particles 221 are formed by a vapor phase method or the like, fine whisker-like protrusions are formed on the surface thereof, and thus voids 225 are generated between the protrusions. This void 225 causes an increase in the surface area of the negative electrode active material particles 221 and also increases the amount of irreversible film formed on the surface, which causes a reduction in the degree of progress of the electrode reaction (charge / discharge reaction). there is a possibility. Therefore, the metal material 226 is embedded in the above-described gap 225 in order to suppress a decrease in the progress of the electrode reaction. In this case, it is sufficient that a part of the gap 225 is embedded, but it is preferable that the amount to be embedded is larger. This is because a decrease in the degree of progress of the electrode reaction is further suppressed. In FIG. 6, the fact that the metal material 226 is scattered on the surface of the uppermost negative electrode active material particle 221 indicates that the above-described fine protrusions are present at the spot. Of course, the metal material 226 does not necessarily have to be scattered on the surface of the negative electrode active material particle 221, and may cover the entire surface.

  In particular, the metal material 226 that has entered the gap 224B also functions to fill the gap 225 in each layer. Specifically, when the negative electrode material is deposited a plurality of times, the fine protrusions described above are generated on the surface of the negative electrode active material particles 221 every time the negative electrode material is deposited. From this, the metal material 226 not only fills the gap 224B in each layer, but also fills the gap 225 in each layer.

  5 and 6, the negative electrode active material particles 221 have a multilayer structure, and the case where both the gaps 224A and 224B exist in the negative electrode active material layer 22B has been described. 22B has a metal material 226 in the gaps 224A and 224B. On the other hand, when the negative electrode active material particle 221 has a single layer structure and only the gap 224A exists in the negative electrode active material layer 22B, the negative electrode active material layer 22B has the metal material 226 only in the gap 224A. It will have. Of course, since the gap 225 is generated in both cases, the gap 225 has the metal material 226 in either case.

  The separator 23 is impregnated with the above-described electrolytic solution. The separator 23 separates the positive electrode 21 and the negative electrode 22 and allows lithium ions to pass through while preventing a short circuit of current caused by contact between the two electrodes. The separator 23 is made of, for example, a porous film made of a synthetic resin such as polytetrafluoroethylene, polypropylene, or polyethylene, or a porous film made of ceramic, and two or more kinds of these porous films are laminated. It may be what was done.

  This secondary battery is manufactured, for example, by the following procedure.

  First, the positive electrode 21 is produced. First, a positive electrode active material, a positive electrode binder, and a positive electrode conductive agent are mixed to form a positive electrode mixture, and then dispersed in an organic solvent to obtain a paste-like positive electrode mixture slurry. Subsequently, using a doctor blade or a bar coater, the positive electrode mixture slurry is uniformly applied to both surfaces of the positive electrode current collector 21A and dried. Finally, the positive electrode active material layer 21B is formed by compression molding the coating film using a roll press machine or the like while heating as necessary. In this case, compression molding may be repeated a plurality of times.

  Next, the negative electrode 22 is produced. First, after preparing a negative electrode current collector 22A made of electrolytic copper foil or the like, a negative electrode material is deposited on both surfaces of the negative electrode current collector 22A by using a vapor phase method such as a vapor deposition method, and a plurality of negative electrode active material particles Form. After that, if necessary, an oxide-containing film is formed using a liquid phase method such as a liquid phase deposition method, or a metal material is formed using a liquid phase method such as an electrolytic plating method, or both are formed. Thus, the negative electrode active material layer 22B is formed.

  The secondary battery is assembled as follows. First, the positive electrode lead 25 is attached to the positive electrode current collector 21A by welding or the like, and the negative electrode lead 26 is attached to the negative electrode current collector 22A by welding or the like. Subsequently, after the positive electrode 21 and the negative electrode 22 are stacked and wound through the separator 23 to produce the wound electrode body 20, the center pin 24 is inserted into the winding center. Subsequently, the wound electrode body 20 is housed in the battery can 11 while being sandwiched between the pair of insulating plates 12 and 13, the tip of the positive electrode lead 25 is welded to the safety valve mechanism 15, and the tip of the negative electrode lead 26 is attached. Weld to battery can 11. Subsequently, the electrolytic solution described above is injected into the battery can 11 and impregnated in the separator 23. Finally, the battery lid 14, the safety valve mechanism 15, and the heat sensitive resistance element 16 are fixed to the opening end of the battery can 11 by caulking through the gasket 17. Thereby, the secondary battery shown in FIGS. 1 and 2 is completed.

  In the secondary battery, when charged, for example, lithium ions are extracted from the positive electrode 21 and inserted in the negative electrode 22 through the electrolytic solution impregnated in the separator 23. On the other hand, when discharging is performed, for example, lithium ions are released from the negative electrode 22 and inserted into the positive electrode 21 through the electrolytic solution impregnated in the separator 23.

  According to this cylindrical secondary battery, when the capacity of the negative electrode 22 is expressed on the basis of insertion and extraction of lithium, the above-described electrolytic solution is provided. It is suppressed. Therefore, cycle characteristics and storage characteristics can be improved.

  In particular, cycle characteristics and storage when the anode 22 contains silicon or the like (a material that can occlude and release lithium and has at least one of a metal element and a metalloid element) that is advantageous for increasing the capacity. Since the characteristics are improved, a higher effect can be obtained than when other negative electrode materials such as a carbon material are included.

  Other effects relating to the secondary battery are the same as those of the above-described electrolytic solution.

(Secondary secondary battery)
The second secondary battery has the same configuration, operation, and effect as the first secondary battery except that the configuration of the negative electrode 22 is different, and is manufactured by the same procedure.

  The negative electrode 22 is provided with a negative electrode active material layer 22B on both surfaces of a negative electrode current collector 22A, as in the first secondary battery. The negative electrode active material layer 22B includes, for example, a material having silicon or tin as a constituent element as a negative electrode active material. Specifically, for example, a simple substance, an alloy or a compound of silicon, or a simple substance, an alloy or a compound of tin is included, and two or more kinds thereof may be included.

  The negative electrode active material layer 22B is formed by using a vapor phase method, a liquid phase method, a thermal spraying method, a firing method, or two or more of these methods. The negative electrode active material layer 22B and the negative electrode current collector It is preferable that 22A is alloyed in at least a part of the interface. Specifically, at the interface, the constituent elements of the negative electrode current collector 22A may diffuse into the negative electrode active material layer 22B, or the constituent elements of the negative electrode active material layer 22B diffuse into the negative electrode current collector 22A. Alternatively, both constituent elements may be diffused with each other. This is because, during charging / discharging, breakage due to expansion and contraction of the negative electrode active material layer 22B is suppressed, and electronic conductivity between the negative electrode active material layer 22B and the negative electrode current collector 22A is improved.

  As the vapor phase method, for example, physical deposition method or chemical deposition method, specifically, vacuum evaporation method, sputtering method, ion plating method, laser ablation method, thermal chemical vapor deposition CVD method or plasma chemical vapor phase Examples include growth methods. As the liquid phase method, a known method such as electroplating or electroless plating can be used. The firing method is, for example, a method in which a particulate negative electrode active material is mixed with a binder, dispersed in a solvent, applied, and then heat-treated at a temperature higher than the melting point of the binder. A known method can also be used for the firing method, for example, an atmospheric firing method, a reactive firing method, or a hot press firing method.

(Third secondary battery)
The third secondary battery is a lithium metal secondary battery in which the capacity of the negative electrode 22 is expressed based on precipitation and dissolution of lithium. This secondary battery has the same configuration as the first secondary battery except that the negative electrode active material layer 22B is made of lithium metal, and is manufactured by the same procedure.

  This secondary battery uses lithium metal as a negative electrode active material, and can thereby obtain a high energy density. The negative electrode active material layer 22B may already exist from the time of assembly, but may not be present at the time of assembly, and may be configured by lithium metal deposited during charging. Further, the negative electrode current collector 22A may be omitted by using the negative electrode active material layer 22B as a current collector.

  In this secondary battery, when charged, for example, lithium ions are extracted from the positive electrode 21 and deposited as lithium metal on the surface of the negative electrode current collector 22A through the electrolyte solution impregnated in the separator 23. On the other hand, when discharging is performed, for example, lithium metal is eluted from the negative electrode active material layer 22 </ b> B as lithium ions, and is inserted in the positive electrode 21 through the electrolytic solution impregnated in the separator 23.

  According to this cylindrical secondary battery, when the capacity of the negative electrode 22 is expressed based on the precipitation and dissolution of lithium, the above-described electrolytic solution is provided, so that cycle characteristics and storage characteristics can be improved. it can. Other effects relating to the secondary battery are the same as those of the first secondary battery described above.

(Fourth secondary battery)
FIG. 7 shows an exploded perspective configuration of the fourth secondary battery, and FIG. 8 shows an enlarged cross section taken along line VIII-VIII of the spirally wound electrode body 30 shown in FIG.

  The secondary battery is, for example, a lithium ion secondary battery, similar to the first secondary battery described above, and the positive electrode lead 31 and the negative electrode lead 32 are mainly attached to the inside of the film-shaped exterior member 40. The wound electrode body 30 is accommodated. The battery structure using the film-shaped exterior member 40 is called a laminate film type.

  For example, the positive electrode lead 31 and the negative electrode lead 32 are led out in the same direction from the inside of the exterior member 40 toward the outside. The positive electrode lead 31 is made of, for example, a metal material such as aluminum, and the negative electrode lead 32 is made of, for example, a metal material such as copper, nickel, or stainless steel. These metal materials are, for example, in a thin plate shape or a mesh shape.

  The exterior member 40 is made of, for example, an aluminum laminated film in which a nylon film, an aluminum foil, and a polyethylene film are bonded together in this order. The exterior member 40 has a structure in which, for example, outer edges of two rectangular aluminum laminate films are bonded to each other by fusion or an adhesive so that the polyethylene film faces the wound electrode body 30. ing.

  An adhesive film 41 is inserted between the exterior member 40 and the positive electrode lead 31 and the negative electrode lead 32 to prevent intrusion of outside air. The adhesion film 41 is made of a material having adhesion to the positive electrode lead 31 and the negative electrode lead 32. Examples of such a material include polyolefin resins such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene.

  In addition, the exterior member 40 may be constituted by a laminate film having another laminated structure instead of the above-described aluminum laminate film, or may be constituted by a polymer film such as polypropylene or a metal film.

  The electrode winding body 30 is obtained by laminating and winding a positive electrode 33 and a negative electrode 34 via a separator 35 and an electrolyte 36, and an outermost peripheral portion thereof is protected by a protective tape 37.

  In the positive electrode 33, for example, a positive electrode active material layer 33B is provided on both surfaces of a positive electrode current collector 33A. The negative electrode 34 is, for example, provided with a negative electrode active material layer 34B on both surfaces of a negative electrode current collector 34A, and the negative electrode active material layer 34B is disposed so as to face the positive electrode active material layer 33B. The configuration of the positive electrode current collector 33A, the positive electrode active material layer 33B, the negative electrode current collector 34A, the negative electrode active material layer 34B, and the separator 35 is the same as that of the positive electrode current collector 21A and the positive electrode active material layer in the first secondary battery described above. The configurations of 21B, the negative electrode current collector 22A, the negative electrode active material layer 22B, and the separator 23 are the same.

  The electrolyte 36 is a so-called gel electrolyte that contains an electrolytic solution and a polymer compound that holds the electrolytic solution. The gel electrolyte is preferable because high ion conductivity (for example, 1 mS / cm or more at room temperature) is obtained and liquid leakage is prevented.

  The composition of the electrolytic solution is the same as the composition of the electrolytic solution in the first secondary battery described above.

  Examples of the polymer compound include polyacrylonitrile, polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and polyhexafluoropyrene, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene, poly Examples thereof include siloxane, polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene, and polycarbonate. These may be single and multiple types may be mixed. Among these, polyacrylonitrile, polyvinylidene fluoride, polyhexafluoropropylene or polyethylene oxide is preferable. This is because it is electrochemically stable.

  In the electrolyte 36 which is a gel electrolyte, the solvent of the electrolytic solution is a wide concept including not only a liquid solvent but also an ion conductive substance capable of dissociating the electrolyte salt. Accordingly, when a polymer compound having ion conductivity is used, the polymer compound is also included in the solvent.

  Instead of the gel electrolyte 36 in which the electrolytic solution is held by the polymer compound, the electrolytic solution may be used as it is. In this case, the separator 35 is impregnated with the electrolytic solution.

  This secondary battery is manufactured by the following three types of manufacturing methods, for example.

  In the first manufacturing method, first, the positive electrode active material layer 33B is formed on both surfaces of the positive electrode current collector 33A, for example, by the same procedure as the positive electrode 21 and the negative electrode 22 in the first secondary battery described above. Thus, the negative electrode 34 is manufactured by forming the negative electrode active material layer 34B on both surfaces of the negative electrode current collector 34A. Then, after preparing the precursor solution containing electrolyte solution, a high molecular compound, and a solvent and apply | coating to the positive electrode 33 and the negative electrode 34, the solvent is volatilized and the gel electrolyte 36 is formed. Subsequently, the positive electrode lead 31 is attached to the positive electrode current collector 33A, and the negative electrode lead 32 is attached to the negative electrode current collector 34A. Subsequently, the positive electrode 33 and the negative electrode 34 on which the electrolyte 36 is formed are stacked via the separator 35 and then wound in the longitudinal direction, and a protective tape 37 is adhered to the outermost peripheral portion to produce the wound electrode body 30. To do. Finally, for example, after the wound electrode body 30 is sandwiched between two film-shaped exterior members 40, the outer edge portions of the exterior member 40 are bonded to each other by heat fusion or the like, so that the wound electrode body 30 is Encapsulate. At this time, the adhesion film 41 is inserted between the positive electrode lead 31 and the negative electrode lead 32 and the exterior member 40. Thereby, the secondary battery shown in FIGS. 7 and 8 is completed.

  In the second manufacturing method, first, the positive electrode lead 31 is attached to the positive electrode 33 and the negative electrode lead 32 is attached to the negative electrode 34. Subsequently, after the positive electrode 33 and the negative electrode 34 are laminated and wound via the separator 35, a protective tape 37 is adhered to the outermost peripheral portion thereof, and a wound body that is a precursor of the wound electrode body 30. Is made. Subsequently, after sandwiching the wound body between the two film-shaped exterior members 40, the remaining outer peripheral edge except for the outer peripheral edge on one side is adhered by heat fusion or the like, thereby forming a bag-shaped exterior The wound body is accommodated in the member 40. Subsequently, an electrolyte composition containing an electrolytic solution, a monomer that is a raw material of the polymer compound, a polymerization initiator, and other materials such as a polymerization inhibitor as necessary is prepared to form a bag-shaped exterior member. After injecting into the inside of 40, the opening part of the exterior member 40 is sealed by heat sealing or the like. Finally, the gel electrolyte 36 is formed by thermally polymerizing the monomer to obtain a polymer compound. Thereby, the secondary battery is completed.

  In the third manufacturing method, a wound body is formed by forming a wound body in the same manner as in the second manufacturing method described above except that the separator 35 coated with the polymer compound on both sides is used first. 40 is housed inside. Examples of the polymer compound applied to the separator 35 include a polymer containing vinylidene fluoride as a component, that is, a homopolymer, a copolymer, or a multi-component copolymer. Specifically, polyvinylidene fluoride, binary copolymers containing vinylidene fluoride and hexafluoropropylene as components, and ternary copolymers containing vinylidene fluoride, hexafluoropropylene and chlorotrifluoroethylene as components. Such as coalescence. In addition, the high molecular compound may contain the other 1 type, or 2 or more types of high molecular compound with the polymer which uses the above-mentioned vinylidene fluoride as a component. Subsequently, after the electrolytic solution is prepared and injected into the exterior member 40, the opening of the exterior member 40 is sealed by heat fusion or the like. Finally, the exterior member 40 is heated while applying a load, and the separator 35 is brought into close contact with the positive electrode 33 and the negative electrode 34 through the polymer compound. As a result, the electrolytic solution is impregnated into the polymer compound, and the polymer compound is gelled to form the electrolyte 36. Thus, the secondary battery is completed.

  In the third manufacturing method, the swollenness of the secondary battery is suppressed as compared with the first manufacturing method. Further, in the third manufacturing method, compared with the second manufacturing method, there are hardly any monomers or solvents that are raw materials for the polymer compound remaining in the electrolyte 36, and the formation process of the polymer compound is well controlled. Therefore, sufficient adhesion is obtained between the positive electrode 33, the negative electrode 34, the separator 35, and the electrolyte 36.

  According to this laminated film type secondary battery, when the capacity of the negative electrode 34 is expressed based on insertion and extraction of lithium, the above-described electrolytic solution is provided, so that the same as the first secondary battery. , Cycle characteristics and storage characteristics can be improved. The effects of the secondary battery other than those described above are the same as those of the first secondary battery.

  Of course, the laminated film type secondary battery is not limited to the same configuration as the first secondary battery, and may have the same configuration as the second or third secondary battery.

  Specific examples of the present invention will be described in detail.

(1) Compound shown in Chemical formula 4 First, using the compound shown in Chemical formula 4 as the nitrile compound shown in Chemical formula 3, the laminate film type secondary battery shown in FIGS. 7 and 8 was produced.

(Example 1-1)
By the following procedure, a secondary battery was manufactured using silicon, which is a material capable of inserting and extracting lithium as a negative electrode active material and having at least one of a metal element and a metalloid element. . At this time, a lithium ion secondary battery in which the capacity of the negative electrode 34 is expressed based on insertion and extraction of lithium was made.

First, the positive electrode 33 was produced. First, lithium carbonate (Li ₂ CO ₃ ) and cobalt carbonate (CoCO ₃ ) are mixed at a molar ratio of 0.5: 1, and then calcined in air at 900 ° C. for 5 hours to form a lithium cobalt composite. An oxide (LiCoO ₂ ) was obtained. Subsequently, after mixing 91 parts by mass of lithium cobalt composite oxide as the positive electrode active material, 3 parts by mass of polyvinylidene fluoride as the positive electrode binder, and 6 parts by mass of graphite as the positive electrode conductive agent, a positive electrode mixture was obtained. Dispersed in N-methyl-2-pyrrolidone to obtain a paste-like positive electrode mixture slurry. Subsequently, the positive electrode mixture slurry was uniformly applied to both surfaces of the positive electrode current collector 33A made of a strip-shaped aluminum foil (thickness = 12 μm) using a bar coater, dried, and then compressed using a roll press. Thus, the positive electrode active material layer 33B was formed.

  Next, after preparing a negative electrode current collector 34A (thickness = 15 μm) made of an electrolytic copper foil, silicon was deposited as a negative electrode active material on both surfaces of the negative electrode current collector 34A by using an electron beam evaporation method. The negative electrode 34 was produced by forming the material layer 34B. In the case of forming this negative electrode active material layer 34B, the negative electrode active material particles were formed through 10 deposition steps so that the negative electrode active material particles had a 10-layer structure. At this time, the thickness (total thickness) of the negative electrode active material particles on one side of the negative electrode current collector 34A was 6 μm.

Next, an electrolytic solution was prepared. First, after mixing ethylene carbonate (EC) and diethyl carbonate (DEC), the compound of Chemical Formula 15 (2) was added as the compound shown in Chemical Formula 4 to prepare a solvent. At this time, the mixing ratio of EC and DEC was 30:70 by weight, and the content of the compound of Chemical formula 15 (2) in the solvent was 0.01% by weight. After that, lithium hexafluorophosphate (LiPF ₆ ) was dissolved in the solvent as an electrolyte salt. At this time, the content of lithium hexafluorophosphate was 1 mol / kg with respect to the solvent.

  Finally, a secondary battery was assembled using the electrolytic solution together with the positive electrode 33 and the negative electrode 34. First, the positive electrode lead 31 made of aluminum was welded to one end of the positive electrode current collector 33A, and the negative electrode lead 32 made of nickel was welded to one end of the negative electrode current collector 34A. Subsequently, after laminating and winding the positive electrode 33, the separator 35 (thickness = 25 μm) made of a microporous polypropylene film, and the negative electrode 54, the winding end portion is fixed with a protective tape 37 made of an adhesive tape. Thus, a wound body that is a precursor of the wound electrode body 30 was formed. Subsequently, a laminate film (total thickness) in which a nylon film (thickness = 30 μm), an aluminum foil (thickness = 40 μm), and an unstretched polypropylene film (thickness = 30 μm) are laminated from the outside. = 100 μm), the wound body was sandwiched between the exterior members 40, and the outer edges except for one side were heat-sealed to accommodate the wound body inside the bag-shaped exterior member 40. Subsequently, an electrolytic solution was injected from the opening of the exterior member 40 and impregnated in the separator 35 to produce the wound electrode body 30. Finally, the laminated film type secondary battery was completed by thermally sealing and sealing the opening of the exterior member 40 in a vacuum atmosphere. For this secondary battery, the thickness of the positive electrode active material layer 33B was adjusted so that lithium metal did not deposit on the negative electrode 34 during full charge.

(Examples 1-2 to 1-7)
The content of the compound of Chemical Formula 15 (2) is 0.5 wt% (Example 1-2), 1 wt% (Example 1-3), 2 wt% (Example 1-4), 3 wt% ( Example 1-5) A procedure similar to that of Example 1-1 was performed, except that the content was 5% by weight (Example 1-6) or 10% by weight (Example 1-7).

(Examples 1-8 to 1-12)
In place of the compound of Chemical formula 15 (2), the compound of Chemical formula 7 (2) (Example 1-8), the compound of Chemical formula 7 (6) (Example 1-9), The compound of Chemical formula 9 (1) Example 1-10) Same as Example 1-5 except that the compound of Chemical Formula 9 (2) (Example 1-11) or the compound of Chemical Formula 15 (6) (Example 1-12) was used. I went through the procedure.

(Comparative Example 1-1)
A procedure similar to that of Examples 1-1 to 1-12 was performed, except that the compound of Chemical Formula 15 (2) was not used.

(Comparative Example 1-2)
The same procedure as in Example 1-5 was performed, except that the compound of formula 49 was used instead of the compound of formula 15 (2).

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 1-1 to 1-12 and Comparative Examples 1-1 and 1-2 were examined, the results shown in Table 1 were obtained.

  When examining the cycle characteristics, first, charging and discharging were performed for 2 cycles in an atmosphere at 23 ° C., and the discharge capacity at the second cycle was measured. Subsequently, the battery was repeatedly charged and discharged in the same atmosphere until the total number of cycles reached 100 cycles, and the discharge capacity at the 100th cycle was measured. Finally, room temperature cycle discharge capacity retention ratio (%) = (discharge capacity at the 100th cycle / discharge capacity at the second cycle) × 100 was calculated. As charging / discharging conditions, constant current and constant voltage charging was performed up to an upper limit voltage of 4.2 V at a current of 0.2 C, and then constant current discharging was performed up to a final voltage of 2.7 V at a current of 0.2 C. This “0.2 C” is a current value at which the theoretical capacity can be discharged in 5 hours.

  When examining the storage characteristics, first, charging and discharging were performed for 2 cycles in an atmosphere at 23 ° C., and the discharge capacity before storage was measured. Subsequently, the battery was stored again in a constant temperature bath at 80 ° C. for 10 days while being charged again, and then discharged in an atmosphere at 23 ° C., and the discharge capacity after storage was measured. Finally, high temperature storage discharge capacity retention rate (%) = (discharge capacity after storage / discharge capacity before storage) × 100 was calculated. The charge / discharge conditions were the same as when the cycle characteristics were examined.

  The procedures and conditions for examining the cycle characteristics and storage characteristics described above are the same for the series of examples and comparative examples described below.

  As shown in Table 1, in the case of containing silicon as the negative electrode active material, in Examples 1-1 to 1-12 in which the solvent contains the compound of Chemical Formula 15 (2) and the like, Comparative Example 1 not containing them Compared with -1 and 1-2, a high normal temperature cycle discharge capacity retention ratio and a high temperature storage discharge capacity retention ratio were obtained without depending on the type and content of the nitrile compound.

  Specifically, in Examples 1-5 and 1-8 to 1-12 in which the types of nitrile compounds are different, the room temperature cycle discharge capacity retention rate and the high temperature storage discharge capacity retention rate were substantially equal.

  Moreover, in Examples 1-1 to 1-7 in which the content of chemical formula 15 (2) is different, both the room temperature cycle discharge capacity retention rate and the high-temperature storage discharge capacity retention rate increased as the content increased. It showed a tendency to decrease later. In this case, when the content was 0.01 wt% or more and 10 wt% or more, the normal temperature cycle discharge capacity maintenance ratio and the high temperature storage discharge capacity maintenance ratio were increased, and the battery capacity was also increased.

  Furthermore, in Comparative Example 1-2 containing the compound of Chemical Formula 49, the high-temperature storage discharge capacity retention rate increased compared to Comparative Example 1-1 not containing it, but the room temperature cycle discharge capacity retention rate was greatly increased. Diminished. On the other hand, in Examples 1-5 and 1-8 to 1-12 containing the compound of Chemical Formula 15 (2) and the like, compared with Comparative Example 1-1, the normal temperature cycle discharge capacity retention rate and high temperature storage The discharge capacity retention rate increased. As a result, in order to increase both the room temperature cycle discharge capacity retention rate and the high temperature storage discharge capacity retention rate, the nitrile group and the electron withdrawing group (—C (═O) — And the like) are advantageous in the case of having a directly bonded site.

  In addition, only the result at the time of using the compound etc. of Chemical formula 15 (2) independently is shown here, and the result at the time of using them in mixture of 2 or more types is not shown. However, as described above, it is obvious that both the normal temperature cycle discharge capacity retention ratio and the high-temperature storage discharge capacity retention ratio increase when the compound of Chemical Formula 15 (2) is used alone. In addition, when the compound of chemical formula 15 (1) is combined, there is no special reason that the normal temperature cycle discharge capacity retention rate and the high temperature storage discharge capacity retention rate are decreased. Therefore, it is apparent that the normal temperature cycle discharge capacity retention ratio and the high-temperature storage discharge capacity retention ratio increase even when two or more compounds of the chemical formula (2) are mixed.

  From these facts, in the secondary battery of the present invention, when the negative electrode 34 contains silicon as the negative electrode active material, the solvent of the electrolytic solution is at least one of the nitrile compounds shown in Chemical formula 3 (compounds shown in Chemical formula 4). It was confirmed that the inclusion of one kind improves the cycle characteristics and the storage characteristics. In this case, it was also confirmed that if the content of the nitrile compound in the solvent is 0.01 wt% or more and 10 wt% or less, excellent battery capacity, cycle characteristics and storage characteristics can be obtained.

(Examples 2-1 and 2-2)
A procedure similar to that in Example 1-5 was performed except that dimethyl carbonate (DMC: Example 2-1) or ethyl methyl carbonate (EMC: Example 2-2) was used instead of DEC as a solvent.

(Example 2-3)
Propyl carbonate (PC) was added as a solvent, and the same procedure as in Example 1-5 was performed except that the mixing ratio (weight ratio) of EC, PC, and DEC was 10:20:70.

(Example 2-4)
A procedure similar to that in Example 1-5 was performed, except that bis (fluoromethyl) carbonate (DFDMC), which is a chain carbonate having a halogen shown in Chemical formula 32, was added as a solvent. At this time, the content of DFDMC in the solvent was 5% by weight.

(Examples 2-5 and 2-6)
As a solvent, 4-fluoro-1,3-dioxolan-2-one (FEC: Example 2-5) which is a cyclic carbonate having a halogen shown in Chemical formula 33, or trans-4,5-difluoro-1, The same procedure as in Example 1-5 was followed, except that 3-dioxolan-2-one (t-DFEC: Example 2-6) was added. At this time, the content of FEC or the like in the solvent was 5% by weight.

(Example 2-7)
A procedure similar to that in Example 1-5 was performed, except that vinylene carbonate (VC), which is a cyclic carbonate having an unsaturated bond shown in Chemical formula 36, was added as a solvent. At this time, the content of VC in the solvent was 5% by weight.

(Comparative Examples 2-1 to 2-3)
The same procedure as in Examples 2-5 to 2-7 was performed, except that the compound of Chemical Formula 15 (2) was not used.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 2-1 to 2-7 and Comparative Examples 2-1 to 2-3 were examined, the results shown in Table 2 were obtained.

  As shown in Table 2, also in Examples 2-1 to 2-7 in which the composition of the solvent was changed, it was compared with Comparative Examples 1-1, 2-1 to 2-3 as in Example 1-5. Thus, a high normal temperature cycle discharge capacity maintenance rate and a high temperature storage discharge capacity maintenance rate were obtained.

  In particular, in Examples 2-1 to 2-3 in which DEC is changed to DMC or the like or PC is added, the normal temperature cycle discharge capacity maintenance rate and the high-temperature storage discharge capacity maintenance rate are higher than those in Example 1-3. It became almost equal or better.

  Moreover, in Examples 2-4 to 2-7 to which FEC, VC, and the like were added, the room temperature cycle discharge capacity retention rate and the high-temperature storage discharge capacity retention rate were higher than those in Example 1-5. In this case, as is clear from the comparison between Examples 2-5 and 2-6, as the number of halogens increased, the room temperature cycle discharge capacity retention rate and the high-temperature storage discharge capacity retention rate increased.

  Here, only the results in the case of using a cyclic carbonate (vinylene carbonate compound) having an unsaturated bond shown in Chemical formula 36 as a solvent are shown, and the unsaturated bond shown in Chemical formula 37 or Chemical formula 38 is shown. The results are not shown when the cyclic carbonate (such as vinyl ethylene carbonate compound) is used. However, since the vinyl ethylene carbonate compound and the like function to increase the normal temperature cycle discharge capacity maintenance rate and the high temperature storage discharge capacity maintenance rate in the same manner as the vinylene carbonate compound, the case where the latter is used even when the former is used. It is clear that similar results are obtained.

  From these facts, it was confirmed that in the secondary battery of the present invention, when the negative electrode 34 contains silicon as the negative electrode active material, the cycle characteristics and the storage characteristics are improved even if the composition of the solvent is changed. In this case, as the solvent, at least one of a chain carbonate having a halogen shown in Chemical formula 32 and a cyclic carbonate having a halogen shown in Chemical formula 33, or the unsaturated compound shown in Chemical formulas 36 to 38 is used. It was also confirmed that if at least one of cyclic carbonates having a bond was used, the characteristics were further improved. In particular, when a chain carbonate having halogen or a cyclic carbonate having halogen is used, the characteristics are further improved as the number of halogens is increased.

(Examples 3-1 to 3-3)
Examples of the electrolyte salt include lithium tetrafluoroborate (LiBF ₄ : Example 3-1), the compound shown in Chemical Formula 42 (6) (Example 3-2) or the chemical formula 45 shown in Chemical Formula 39. The same procedure as in Example 1-5 was performed, except that the compound shown was bis (trifluoromethanesulfonyl) imidolithium (LiTFSI: Example 3-3). At this time, the content of lithium hexafluorophosphate was 0.9 mol / kg with respect to the solvent, and the content of lithium tetrafluoroborate and the like was 0.1 mol / kg with respect to the solvent.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 3-1 to 3-3 were examined, the results shown in Table 3 were obtained.

  As shown in Table 3, in Examples 3-1 to 3-3 in which the type of the electrolyte salt was changed, compared with Example 1-5, the room temperature cycle discharge capacity retention rate and high-temperature storage discharge capacity equal to or higher than those of Example 1-5 A retention rate was obtained.

  Here, only the results when lithium tetrafluoroborate or a compound shown in Chemical Formula 39 or Chemical Formula 45 is used as the electrolyte salt are shown, and lithium perchlorate, lithium hexafluoroarsenate, or The results when using the compounds shown in Chemical Formula 40, Chemical Formula 41, Chemical Formula 46 or Chemical Formula 47 are not shown. However, lithium perchlorate and the like, like lithium tetrafluoroborate, have the function of increasing the normal temperature cycle discharge capacity maintenance rate and the high-temperature storage discharge capacity maintenance rate, so the latter is used even when the former is used. It is clear that the same results as those obtained were obtained.

  From these, it was confirmed that in the secondary battery of the present invention, when the negative electrode 34 contains silicon as the negative electrode active material, the cycle characteristics and the storage characteristics are improved even if the type of the electrolyte salt is changed. In this case, as the electrolyte salt, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, a compound shown in Chemical formula 39 to Chemical formula 41, or a compound shown in Chemical formula 45 to Chemical formula 47 can be used. It was also confirmed that the characteristics were further improved.

(Example 4-1)
As the negative electrode active material, a negative electrode active material can be used by using SnCoC-containing material, which is a material that can occlude and release lithium in the same way as silicon and has at least one of a metal element and a metalloid element. The same procedure as in Example 1-5 was performed except that the material layer 34B was formed.

  In forming this negative electrode active material layer 34B, first, cobalt powder and tin powder were alloyed to form cobalt-tin alloy powder, and then carbon powder was added and dry mixed. Subsequently, 10 g of the above mixture was set together with about 400 g of steel balls having a diameter of 9 mm in a reaction vessel of a planetary ball mill manufactured by Ito Seisakusho. Subsequently, after replacing the inside of the reaction vessel with an argon atmosphere, an operation for 10 minutes and a pause for 10 minutes at a rotation speed of 250 revolutions per minute were repeated until the total operation time reached 20 hours. Subsequently, after the reaction vessel was cooled to room temperature and the SnCoC-containing material was taken out, the coarse powder was removed through a 280 mesh sieve.

  When the composition of the obtained SnCoC-containing material was analyzed, the content of tin was 49.5% by mass, the content of cobalt was 29.7% by mass, the content of carbon was 19.8% by mass, tin and cobalt The ratio of cobalt to the total of (Co / (Sn + Co)) was 37.5% by mass. At this time, the tin and cobalt contents were measured by inductively coupled plasma (ICP) emission analysis, and the carbon content was measured by a carbon / sulfur analyzer. Further, when the SnCoC-containing material was analyzed by the X-ray diffraction method, a diffraction peak having a half width in the range of 2θ = 20 ° to 50 ° was observed. Further, when the SnCoC-containing material was analyzed by XPS, a peak P1 was obtained as shown in FIG. When this peak P1 was analyzed, a peak P2 of surface contamination carbon and a peak P3 of C1s in the SnCoC-containing material on the lower energy side (region lower than 284.5 eV) were obtained. From this result, it was confirmed that carbon in the SnCoC-containing material was bonded to other elements.

  After obtaining the SnCoC-containing material, 80 parts by mass of the SnCoC-containing material as the negative electrode active material, 8 parts by mass of polyvinylidene fluoride as the negative electrode binder, 11 parts by mass of graphite and 1 part by mass of acetylene black as the negative electrode conductive agent After preparing a negative electrode mixture, it was dispersed in N-methyl-2-pyrrolidone to obtain a paste-like negative electrode mixture slurry. Subsequently, the negative electrode mixture slurry was uniformly applied to both surfaces of the negative electrode current collector 34A made of a strip-shaped electrolytic copper foil (thickness = 15 μm) using a bar coater, and then dried, and then a roll press machine was used. The coating film was compression molded. At this time, the thickness of the negative electrode active material layer 34B on one side of the negative electrode current collector 34A was set to 50 μm.

(Example 4-2)
As in Example 4-1, the same procedure as in Example 2-5 was performed except that a SnCoC-containing material was used as the negative electrode active material.

(Comparative Examples 3-1 and 3-2)
The same procedure as in Examples 4-1 and 4-2 was performed, except that the compound of Chemical Formula 15 (2) was not used.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 4-1 and 4-2 and Comparative examples 3-1 and 3-2 were examined, the results shown in Table 4 were obtained.

  As shown in Table 4, even when the SnCoC-containing material was used as the negative electrode active material, the same results as those shown in Table 1 and Table 2 were obtained. That is, in Examples 4-1 and 4-2 in which the solvent contains the compound of Chemical formula 15 (2), compared with Comparative Examples 3-1 and 3-2 that do not contain the compound, a higher normal temperature cycle discharge capacity retention rate And the high temperature storage discharge capacity maintenance rate was obtained. Moreover, in Example 4-2 which added FEC as a solvent, the normal temperature cycle discharge capacity maintenance rate and the high temperature storage discharge capacity maintenance rate became high compared with Example 4-1.

  Here, only the result when the compound of the chemical formula 15 (2) is used is shown, and the result when the compound of the chemical formula 7 (2) or the like is used is not shown. However, from the results shown in Table 1, when the same material (silicon) is used as the negative electrode active material, by including the compound of chemical formula 15 (2), etc., the normal temperature cycle discharge capacity retention rate and the high temperature storage discharge It is clear that the capacity maintenance rate is improved. From this, even when another same material (SnCoC-containing material) is used as the negative electrode active material, the room temperature cycle discharge capacity maintenance rate and the high-temperature storage discharge are obtained by containing the compound of chemical formula 15 (2). It is clear that the capacity maintenance rate is improved.

  From these facts, in the secondary battery of the present invention, when the negative electrode 34 contains a SnCoC-containing material as the negative electrode active material, the solvent of the electrolytic solution is the nitrile compound (compound shown in chemical formula 4) shown in chemical formula 3 It was confirmed that the cycle characteristics and the storage characteristics were improved by containing at least one of the above.

(Examples 5-1 to 5-11)
As in the case of Examples 1-1 to 1-4 and 1-6 to 1-12, except that the negative electrode active material layer 34B was formed using artificial graphite, which is a carbon material, instead of silicon as the negative electrode active material. I went through the procedure. When forming this negative electrode active material layer 34B, a negative electrode mixture in which 90 parts by mass of artificial graphite as a negative electrode active material and 10 parts by mass of polyvinylidene fluoride as a negative electrode binder is mixed is N-methyl-2-pyrrolidone. A paste-like positive electrode mixture slurry is dispersed in a negative electrode mixture slurry, and the negative electrode mixture slurry is uniformly applied to both sides of the negative electrode current collector 34A made of a strip-like electrolytic copper foil (thickness = 15 μm) using a bar coater and dried. After that, compression molding was performed using a roll press. At this time, the thickness of the negative electrode active material layer 34B on one side of the negative electrode current collector 34A was set to 72.5 μm.

(Comparative Examples 4-1 and 4-2)
The procedure was similar to that of Comparative Examples 1-1 and 1-2, except that artificial graphite was used as in Examples 5-1 to 5-11.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 5-1 to 5-11 and Comparative examples 4-1 and 4-2 were examined, the results shown in Table 5 were obtained.

  As shown in Table 5, the same results as in Table 1 were obtained even when artificial graphite was used as the negative electrode active material. That is, in Examples 5-1 to 5-11 in which the solvent contains the compound of Chemical Formula 15 (2) and the like, compared with Comparative Examples 4-1 and 4-2 that do not contain them, high room temperature cycle discharge capacity maintenance Rate and high temperature storage discharge capacity retention rate were obtained. In Examples 5-1 to 5-6, when the content of the nitrile compound in the solvent was 0.01% by weight or more and 10% by weight or less, the battery capacity was also increased.

  From these facts, in the secondary battery of the present invention, when the negative electrode 34 includes artificial graphite as the negative electrode active material, the solvent of the electrolytic solution is a nitrile compound (compound shown in chemical formula 4) shown in chemical formula 3 It was confirmed that the cycle characteristics and the storage characteristics were improved by containing at least one kind. In this case, it was also confirmed that if the content of the nitrile compound in the solvent is 0.01 wt% or more and 10 wt% or less, excellent battery capacity, cycle characteristics and storage characteristics can be obtained.

(Examples 6-1 to 6-7)
The same procedure as in Examples 2-1 to 2-7 was performed except that artificial graphite was used as the negative electrode active material in the same manner as in Examples 5-1 to 5-11.

(Comparative Examples 5-1 to 5-3)
A procedure similar to that of Comparative Examples 2-1 to 2-3 was performed except that artificial graphite was used as the negative electrode active material in the same manner as in Examples 5-1 to 5-11.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 6-1 to 6-7 and Comparative Examples 5-1 to 5-3 were examined, the results shown in Table 6 were obtained.

  As shown in Table 6, when artificial graphite was used as the negative electrode active material, the same results as in Table 2 were obtained. That is, also in Examples 6-1 to 6-7 in which the composition of the solvent was changed, as in Example 5-3, compared with Comparative Examples 4-1, 5-1 to 5-3, a higher room temperature cycle. A discharge capacity retention ratio and a high temperature storage discharge capacity retention ratio were obtained. In addition, in Examples 6-4 to 6-7 to which FEC, VC, and the like were added, the room temperature cycle discharge capacity maintenance rate and the high-temperature storage discharge capacity maintenance rate were higher than those in Example 5-3 not containing them. It was.

  From these, it was confirmed that in the secondary battery of the present invention, when the negative electrode 34 contains artificial graphite as the negative electrode active material, the cycle characteristics and the storage characteristics are improved even if the composition of the solvent is changed. In this case, as the solvent, at least one of a chain carbonate having a halogen shown in Chemical formula 32 and a cyclic carbonate having a halogen shown in Chemical formula 33, or the unsaturated compound shown in Chemical formulas 36 to 38 is used. It was also confirmed that if at least one of cyclic carbonates having a bond was used, the characteristics were further improved.

(Examples 7-1 to 7-3)
The same procedure as in Examples 3-1 to 3-3 was performed except that artificial graphite was used as the negative electrode active material in the same manner as in Examples 5-1 to 5-11.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 7-1 to 7-3 were examined, the results shown in Table 7 were obtained.

  As shown in Table 7, the same results as in Table 3 were obtained when artificial graphite was used as the negative electrode active material. That is, in Examples 7-1 to 7-3 in which the type of the electrolyte salt was changed, compared with Example 5-3, the room temperature cycle discharge capacity maintenance rate and the high temperature storage discharge capacity maintenance rate equal to or higher than that were obtained. .

  From these, it was confirmed that in the secondary battery of the present invention, when the negative electrode 34 includes artificial graphite as the negative electrode active material, the cycle characteristics and the storage characteristics are improved even if the type of the electrolyte salt is changed. . In this case, as the electrolyte salt, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, a compound shown in Chemical formula 39 to Chemical formula 41, or a compound shown in Chemical formula 45 to Chemical formula 47 can be used. It was also confirmed that the characteristics were further improved.

(Examples 8-1 to 8-3)
In forming the negative electrode active material layer 34B, Examples 1-5, 2-5, 2-, except that after forming a plurality of negative electrode active material particles, an oxide-containing film and a metal material were formed in this order. The same procedure as 6 was performed. In the case of forming an oxide-containing film, silicon oxide (SiO ₂ ) was deposited on the surface of the negative electrode active material particles by a liquid phase deposition method. At this time, the negative electrode current collector 34A on which the negative electrode active material particles are formed is immersed in a solution in which boron as an anion scavenger is dissolved in silicofluoric acid for 3 hours, and silicon is deposited on the surface of the negative electrode active material particles. After the oxide was precipitated, it was washed with water and dried under reduced pressure. In the case of forming a metal material, a cobalt (Co) plating film was grown by an electrolytic plating method. At this time, a cobalt plating solution manufactured by Nippon High Purity Chemical Co., Ltd. was used as the plating solution, the current density was set to 2 A / dm ^{2 to} 5 A / dm ² , the plating rate was set to 10 nm / second, and electricity was supplied while supplying air to the plating bath. Then, cobalt was deposited on both surfaces of the negative electrode current collector 34A.

(Comparative Examples 6-1 to 6-3)
Similar to Examples 8-1 to 8-3, the same procedure as Comparative Examples 1-1, 2-1, and 2-2 was performed, except that an oxide-containing film and a metal material were formed.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 8-1 to 8-3 and Comparative Examples 6-1 to 6-3 were examined, the results shown in Table 8 were obtained.

  As shown in Table 8, when the oxide-containing film and the metal material were formed, the same results as those shown in Table 1 and Table 2 were obtained. That is, in Examples 8-1 to 8-3, as in Example 1-5, compared with Comparative Examples 1-1 and 6-1 to 6-3, a high normal temperature cycle discharge capacity retention rate and high-temperature storage were achieved. A discharge capacity retention rate was obtained.

  In particular, in Example 8-1 in which the oxide-containing film and the metal material were formed, the room temperature cycle discharge maintenance rate and the high-temperature storage discharge capacity maintenance rate were higher than those in Example 1-5 in which they were not formed. It was.

  For these reasons, in the secondary battery of the present invention, even when the negative electrode active material layer 34B includes an oxide-containing film and a metal material, cycle characteristics and storage characteristics are improved, and the oxide-containing film and the metal are improved. It was confirmed that the characteristics were further improved by using the material.

Example 9
In the case of forming the negative electrode active material layer 34B, Example 1-5 except that only the oxide-containing film was formed after forming a plurality of negative electrode active material particles by the procedure described in Example 8-1. The same procedure was followed.

(Comparative Example 7)
As in Example 9, the same procedure as in Comparative Example 1-1 was performed except that an oxide-containing film was formed.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Example 9 and Comparative Example 7 were examined, the results shown in Table 9 were obtained.

  As shown in Table 9, even when only the oxide-containing film was formed, the same results as those shown in Table 1 were obtained. That is, in Example 9, as with Example 1-5, compared with Comparative Examples 1-1 and 7, a higher normal temperature cycle discharge capacity retention rate and high temperature storage discharge capacity retention rate were obtained.

  In particular, in Example 9 in which the oxide-containing film was formed, the room temperature cycle discharge retention rate and the high-temperature storage discharge capacity retention rate were higher than those in Example 1-5 in which the oxide-containing film was not formed.

  Here, only the result when a silicon oxide is formed as the oxide-containing film is shown, and the result when a germanium or tin oxide is formed is not shown. However, germanium and other oxides, like the silicon oxide, have the function of increasing the normal temperature cycle discharge capacity retention rate and the high temperature storage discharge capacity retention rate. It is clear that similar results are obtained. This also applies to the case where two or more kinds of the above series of oxides are mixed in an arbitrary combination.

  From these facts, in the secondary battery of the present invention, even when the negative electrode active material layer 34B includes only the oxide-containing film, the cycle characteristics and the storage characteristics are improved. Has been confirmed to improve.

(Example 10)
When forming the negative electrode active material layer 34B, the same procedure as in Example 1-5 is performed except that only a metal material is formed after forming a plurality of negative electrode active material particles by the procedure described in Example 8-1. I went through the procedure.

(Comparative Example 8)
As in Example 10, the same procedure as in Comparative Example 1-1 was performed except that a metal material was formed.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Example 10 and Comparative Example 8 were examined, the results shown in Table 10 were obtained.

  As shown in Table 10, even when only the metal material was formed, the same results as those shown in Table 1 were obtained. That is, in Example 10, as with Example 1-5, compared with Comparative Examples 1-1 and 8, a higher normal temperature cycle discharge capacity retention rate and high temperature storage discharge capacity retention rate were obtained.

  In particular, in Example 10 in which the metal material was formed, the room temperature cycle discharge maintenance rate and the high-temperature storage discharge capacity maintenance rate were higher than those in Example 1-5 in which the metal material was not formed.

  Here, only the result when a cobalt plating film is formed as a metal material is shown, and the result when an iron, nickel, zinc, or copper plating film is formed is not shown. However, the plating film of iron or the like, like the plating film of cobalt, functions to increase the normal temperature cycle discharge capacity retention rate and the high temperature storage discharge capacity retention rate. It is clear that similar results are obtained. The same applies to the case where two or more kinds of the above-described series of plating films are mixed in any combination.

  From these facts, in the secondary battery of the present invention, even when the negative electrode active material layer 34B contains a metal material, the cycle characteristics and the storage characteristics are improved, and if the metal material is used, the characteristics are further improved. Was confirmed.

  In Example 8-1 in which both the oxide-containing film and the metal material were formed, the normal temperature cycle was compared with Example 9 in which only the oxide-containing film was formed and Example 10 in which only the metal material was formed. Both the discharge capacity retention rate and the high-temperature storage discharge capacity retention rate were sufficiently high.

  Therefore, in the secondary battery of the present invention, when the negative electrode active material layer 34B includes an oxide-containing film and a metal material, excellent cycle characteristics and storage characteristics are obtained as compared with the case where only one of them is included. It was confirmed that it was obtained.

(2) Compound shown in Chemical formula 5 Next, using the compound shown in Chemical formula 5 as the nitrile compound shown in Chemical formula 3, a laminate film type secondary battery was produced.

(Examples 11-1 to 11-7)
A procedure similar to that of Examples 1-1 to 1-7 was performed, except that the compound of Chemical Formula 29 (2) was used as the compound of Chemical Formula 5 instead of the compound of Chemical Formula 15 (2).

(Examples 11-8 and 11-9)
The Example was used except that the compound of Chemical 29 (1) (Example 11-8) or the compound of Chemical 29 (3) (Example 11-9) was used instead of the compound of Chemical 29 (2). The same procedure as in 11-5 was performed.

(Comparative Example 9-1)
The same procedure as in Examples 11-1 to 11-9 was performed, except that the compound of Chemical Formula 29 (2) was not used.

(Comparative Example 9-2)
The same procedure as in Example 11-5 was performed, except that the compound of Formula 50 was used instead of the compound of Formula 29 (2).

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 11-1 to 11-9 and Comparative Examples 9-1 and 9-2 were examined, the results shown in Table 11 were obtained.

  As shown in Table 11, in the case of containing silicon as the negative electrode active material, in Examples 11-1 to 11-9 in which the solvent contains the compound of Chemical Formula 29 (2) and the like, Comparative Example 9 not containing them Compared with -1 and 9-2, a high normal temperature cycle discharge capacity retention ratio and a high temperature storage discharge capacity retention ratio were obtained.

  In particular, in Examples 11-1 to 11-7 having different contents of Chemical 29 (2), when the content is 0.01 wt% or more and 10 wt% or more, the normal temperature cycle discharge capacity maintenance rate and high temperature storage are achieved. The discharge capacity maintenance rate increased, and the battery capacity also increased.

  In addition, only the result at the time of using the compound etc. of Chemical formula 29 (2) independently is shown here, and the result at the time of using them in mixture of 2 or more types is not shown. However, as described above, when the compound of Chemical Formula 29 (2) or the like is used alone, it is clear that both the normal temperature cycle discharge capacity retention rate and the high temperature storage discharge capacity retention rate are increased. In addition, when the compound of Chemical Formula 29 (1) is combined, there is no special reason that the normal temperature cycle discharge capacity retention rate and the high temperature storage discharge capacity retention rate are decreased. Therefore, even when two or more compounds of the chemical formula 29 (2) are mixed, it is clear that the normal temperature cycle discharge capacity retention rate and the high temperature storage discharge capacity retention rate are increased.

  From these facts, in the secondary battery of the present invention, when the negative electrode 34 contains silicon as the negative electrode active material, the solvent of the electrolytic solution is at least one of the nitrile compounds shown in Chemical formula 3 (compounds shown in Chemical formula 5). It was confirmed that the inclusion of one kind improves the cycle characteristics and the storage characteristics. In this case, it was also confirmed that if the content of the nitrile compound in the solvent is 0.01 wt% or more and 10 wt% or less, excellent battery capacity, cycle characteristics and storage characteristics can be obtained.

(Examples 12-1 to 12-7)
The same procedure as in Examples 2-1 to 2-7 was performed except that the compound of Chemical Formula 29 (2) was used in the same manner as in Examples 11-1 to 11-9.

(Comparative Examples 10-1 to 10-3)
The same procedure as in Examples 12-5 to 12-7 was performed, except that the compound of Chemical Formula 29 (2) was not used.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 12-1 to 12-7 and Comparative Examples 10-1 to 10-3 were examined, the results shown in Table 12 were obtained.

  As shown in Table 12, also in Examples 12-1 to 12-7 in which the composition of the solvent was changed, it was compared with Comparative Examples 9-1 and 10-1 to 10-3 in the same manner as Example 11-5. Thus, a high normal temperature cycle discharge capacity maintenance rate and a high temperature storage discharge capacity maintenance rate were obtained.

  In particular, in Examples 12-1 to 12-7 in which DEC was changed to DMC or the like, PC was added, or FEC or VC was added, compared with Example 11-5, the normal temperature cycle discharge capacity retention rate In addition, the high-temperature storage discharge capacity retention rate increased.

  From these facts, it was confirmed that in the secondary battery of the present invention, when the negative electrode 34 contains silicon as the negative electrode active material, the cycle characteristics and the storage characteristics are improved even if the composition of the solvent is changed. In this case, as the solvent, at least one of a chain carbonate having a halogen shown in Chemical formula 32 and a cyclic carbonate having a halogen shown in Chemical formula 33, or the unsaturated compound shown in Chemical formulas 36 to 38 is used. It was also confirmed that if at least one of cyclic carbonates having a bond was used, the characteristics were further improved.

(Examples 13-1 to 13-3)
The same procedure as in Examples 3-1 to 3-3 was performed, except that the compound of Chemical Formula 29 (2) was used in the same manner as in Examples 11-1 to 11-9.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 13-1 to 13-3 were examined, the results shown in Table 13 were obtained.

  As shown in Table 13, in Examples 13-1 to 13-3 in which the type of the electrolyte salt was changed, compared with Example 11-5, the room temperature cycle discharge capacity retention rate and high-temperature storage discharge capacity equal to or higher than those of Example 11-5 A retention rate was obtained.

  From these, it was confirmed that in the secondary battery of the present invention, when the negative electrode 34 contains silicon as the negative electrode active material, the cycle characteristics and the storage characteristics are improved even if the type of the electrolyte salt is changed. In this case, as the electrolyte salt, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, a compound shown in Chemical formula 39 to Chemical formula 41, or a compound shown in Chemical formula 45 to Chemical formula 47 can be used. It was also confirmed that the characteristics were further improved.

(Examples 14-1 and 14-2)
The same procedure as in Examples 4-1 and 4-2 was performed, except that the compound of Chemical Formula 29 (2) was used as the compound of Chemical Formula 5 instead of the compound of Chemical Formula 15 (2).

(Comparative Examples 11-1 and 11-2)
The same procedure as in Examples 14-1 and 14-2 was performed, except that the compound of Chemical Formula 29 (2) was not used.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 14-1 and 14-2 and Comparative Examples 11-1 and 11-2 were examined, the results shown in Table 14 were obtained.

  As shown in Table 14, even when the SnCoC-containing material was used as the negative electrode active material, the same results as those shown in Table 11 and Table 12 were obtained. That is, in Examples 14-1 and 14-2 in which the solvent contains the compound of Chemical Formula 29 (2), compared with Comparative Examples 11-1 and 11-2 that do not contain the compound, a higher normal temperature cycle discharge capacity retention rate And the high temperature storage discharge capacity maintenance rate was obtained. Moreover, in Example 14-2 which added FEC as a solvent, compared with Example 14-1, the normal temperature cycle discharge capacity maintenance rate and the high temperature storage discharge capacity maintenance rate became high.

  From these facts, in the secondary battery of the present invention, when the negative electrode 34 includes a SnCoC-containing material as the negative electrode active material, the solvent of the electrolytic solution is the nitrile compound (compound shown in chemical formula 5) shown in chemical formula 3 It was confirmed that the cycle characteristics and the storage characteristics were improved by containing at least one of the above.

(Examples 15-1 to 15-8)
A procedure similar to that in Examples 11-1 to 11-4 and 11-6 to 11-9 was performed except that artificial graphite was used as in Examples 5-1 to 5-11.

(Comparative Examples 12-1, 12-2)
A procedure similar to that of Comparative Examples 9-1 and 9-2 was performed, except that artificial graphite was used as in Examples 5-1 to 5-11.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 15-1 to 15-8 and Comparative Examples 12-1 and 12-2 were examined, the results shown in Table 15 were obtained.

  As shown in Table 15, the same results as in Table 11 were obtained even when artificial graphite was used as the negative electrode active material. That is, in Examples 15-1 to 15-8 in which the solvent contains the compound of Chemical Formula 29 (2) and the like, compared with Comparative Examples 12-1 and 12-2 that do not contain them, the room temperature cycle discharge capacity is maintained high. Rate and high temperature storage discharge capacity retention rate were obtained. In Examples 15-1 to 15-6, when the content of the nitrile compound in the solvent was 0.01% by weight or more and 10% by weight or less, the battery capacity was also increased.

  From these facts, in the secondary battery of the present invention, when the negative electrode 34 contains artificial graphite as the negative electrode active material, the solvent of the electrolytic solution is the nitrile compound shown in Chemical formula 3 (compound shown in Chemical formula 5). It was confirmed that the cycle characteristics and the storage characteristics were improved by containing at least one kind. In this case, it was also confirmed that if the content of the nitrile compound in the solvent is 0.01 wt% or more and 10 wt% or less, excellent battery capacity, cycle characteristics and storage characteristics can be obtained.

(Examples 16-1 to 16-7)
The same procedure as in Examples 12-1 to 12-7 was performed except that artificial graphite was used as the negative electrode active material in the same manner as in Examples 5-1 to 5-11.

(Comparative Examples 13-1 to 13-3)
The same procedure as in Examples 16-5 to 16-7 was performed, except that the compound of Chemical Formula 29 (2) was not used.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 16-1 to 16-7 and Comparative Examples 13-1 to 13-3 were examined, the results shown in Table 16 were obtained.

  As shown in Table 16, the same results as in Table 12 were obtained when artificial graphite was used as the negative electrode active material. That is, also in Examples 16-1 to 16-7 in which the composition of the solvent was changed, as in Example 15-3, compared with Comparative Examples 12-1, 13-1 to 13-3, a higher room temperature cycle. A discharge capacity retention ratio and a high temperature storage discharge capacity retention ratio were obtained. Moreover, in Examples 16-4 to 16-7 to which FEC, VC, or the like was added, the room temperature cycle discharge capacity maintenance rate and the high-temperature storage discharge capacity maintenance rate were higher than those of Example 15-3 not containing them. It was.

  From these, it was confirmed that in the secondary battery of the present invention, when the negative electrode 34 contains artificial graphite as the negative electrode active material, the cycle characteristics and the storage characteristics are improved even if the composition of the solvent is changed. In this case, as the solvent, at least one of a chain carbonate having a halogen shown in Chemical formula 32 and a cyclic carbonate having a halogen shown in Chemical formula 33, or the unsaturated compound shown in Chemical formulas 36 to 38 is used. It was also confirmed that if at least one of cyclic carbonates having a bond was used, the characteristics were further improved.

(Examples 17-1 to 17-3)
Similar to Examples 5-1 to 5-11, the same procedure as in Examples 13-1 to 13-3 was performed, except that artificial graphite was used as the negative electrode active material.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 17-1 to 17-3 were examined, the results shown in Table 17 were obtained.

  As shown in Table 17, the same results as in Table 13 were obtained when artificial graphite was used as the negative electrode active material. That is, in Examples 17-1 to 17-3 in which the type of the electrolyte salt was changed, compared with Example 15-3, room temperature cycle discharge capacity retention rate and high-temperature storage discharge capacity retention rate equal to or higher than that were obtained. .

  From these, it was confirmed that in the secondary battery of the present invention, when the negative electrode 34 includes artificial graphite as the negative electrode active material, the cycle characteristics and the storage characteristics are improved even if the type of the electrolyte salt is changed. . In this case, as the electrolyte salt, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, a compound shown in Chemical formula 39 to Chemical formula 41, or a compound shown in Chemical formula 45 to Chemical formula 47 can be used. It was also confirmed that the characteristics were further improved.

  Here, only the result when the compound shown in Chemical formula 4 or Chemical formula 5 is used as the nitrile compound shown in Chemical formula 3 is shown, and the result when the compound shown in Chemical formula 6 is used is not shown. . However, since the compound shown in Chemical formula 6 has a part common to the chemical formula shown in Chemical formula 4 or Chemical formula 5 (site where nitrile group and electron-withdrawing group are directly bonded) in the chemical formula, It functions to increase the discharge capacity maintenance rate and the high temperature storage discharge capacity maintenance rate. Thus, it is clear that the same result can be obtained when the former is used as when the latter is used.

  From the results shown in Tables 1 to 17, in the secondary battery of the present invention, when the electrolyte solution contains at least one of the nitrile compounds shown in Chemical Formula 3, the type of the negative electrode active material, the solvent It was confirmed that the cycle characteristics and the storage characteristics were improved without depending on the composition of the electrolyte or the type of the electrolyte salt.

  In this case, as a negative electrode active material, a material that can occlude and release lithium and has at least one of a metal element and a metalloid element as compared with the case where a carbon material (artificial graphite) is used. In the case of using (silicon or SnCoC-containing material), the increasing rate of the discharge capacity retention rate was increased. From this, it was confirmed that a higher effect was obtained in the latter case than in the former case. This result suggests that the use of silicon, which is advantageous for increasing the capacity as the negative electrode active material, makes the electrolyte solution more easily decomposed than when a carbon material is used. It is done.

  The present invention has been described with reference to the embodiments and examples. However, the present invention is not limited to the embodiments described in the above embodiments and examples, and various modifications can be made. For example, the usage application of the electrolytic solution of the present invention is not necessarily limited to a secondary battery, but may be an electrochemical device other than the secondary battery. Other applications include, for example, capacitors.

  In the above-described embodiments and examples, the types of secondary batteries include lithium ion secondary batteries in which the negative electrode capacity is expressed based on insertion and extraction of lithium, and the negative electrode capacity is lithium deposition and dissolution. Although the lithium metal secondary battery expressed based on the above has been described, the present invention is not necessarily limited thereto. The secondary battery of the present invention includes a capacity of the negative electrode including a capacity associated with insertion and extraction of lithium and a capacity associated with precipitation and dissolution of lithium, and a secondary battery represented by the sum of these capacities. The same applies. In this case, a material capable of inserting and extracting lithium is used as the negative electrode active material, and the chargeable capacity of the negative electrode material capable of inserting and extracting lithium is smaller than the discharge capacity of the positive electrode. Thus, the capacity between the positive and negative electrodes is adjusted.

  In the above-described embodiments and examples, the case where the battery structure is a cylindrical type and a laminate film type and the case where the battery element has a winding structure have been described as examples. However, the secondary battery of the present invention is described. Can be similarly applied to cases where other battery structures such as a square shape, a coin shape, and a button shape are provided, and where battery elements have other structures such as a laminated structure.

  In the above-described embodiments and examples, the case where lithium is used as the electrode reactant has been described. However, other group 1 elements such as sodium (Na) or potassium (K), magnesium (Mg) or calcium ( Group 2 elements such as Ca) or other light metals such as aluminum may be used. In these cases, the negative electrode material described in the above embodiment can be used as the negative electrode active material.

  In the above-described embodiments and examples, the appropriate range derived from the results of the examples is described for the content of the nitrile compound shown in Chemical Formula 3 in the electrolytic solution or secondary battery of the present invention. The explanation does not completely deny the possibility that the content is outside the above range. In other words, the appropriate range described above is a particularly preferable range for obtaining the effect of the present invention, and the content may be slightly deviated from the above range as long as the effect of the present invention is obtained.

It is sectional drawing showing the structure of the 1st secondary battery provided with the electrolyte solution which concerns on one embodiment of this invention. It is sectional drawing which expands and represents a part of winding electrode body shown in FIG. FIG. 3 is an enlarged cross-sectional view illustrating a configuration of a negative electrode illustrated in FIG. 2. It is sectional drawing showing the structure of the negative electrode of a reference example. FIG. 3 is an SEM photograph showing a cross-sectional structure of the negative electrode shown in FIG. 2 and a schematic diagram thereof. FIG. 3 is an SEM photograph showing another cross-sectional structure of the negative electrode shown in FIG. 2 and a schematic diagram thereof. It is sectional drawing showing the structure of the 4th secondary battery provided with the electrolyte solution which concerns on one embodiment of this invention. It is sectional drawing along the VIII-VIII line of the wound electrode body shown in FIG. It is a figure showing the analysis result of SnCoC containing material by XPS.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Battery can, 12, 13 ... Insulation board, 14 ... Battery cover, 15 ... Safety valve mechanism, 15A ... Disc board, 16 ... Heat sensitive resistance element, 17 ... Gasket, 20, 30 ... Winding electrode body, 21, 33 ... Positive electrode, 21A, 33A ... Positive electrode current collector, 21B, 33B ... Positive electrode active material layer, 22, 34 ... Negative electrode, 22A, 34A ... Negative electrode current collector, 22B, 34B ... Negative electrode active material layer, 23, 35 ... Separator 24 ... Center pin, 25, 31 ... Positive electrode lead, 26, 32 ... Negative electrode lead, 36 ... Electrolyte, 37 ... Protective tape, 40 ... Exterior member, 41 ... Adhesive film, 221 ... Negative electrode active material particle, 222 ... Oxide Containing film, 224 (224A, 224B) ... gap, 225 ... gap, 226 ... metal material.

Claims (14)

An electrolyte is provided together with the positive electrode and the negative electrode,
The said electrolyte solution is a secondary battery containing the nonaqueous solvent containing at least 1 sort (s) of the nitrile compound represented by Chemical formula 1.

(R is a z-valent organic group having carbon (C) and at least one of hydrogen (H) and halogen as constituent elements , and X is -C (= O)-, -O-C (= O )-, -S (= O)-, -OS (= O)-, -S (= O) _2- , or -O-S (= O) _2- , and z is an integer of 1 or more. However, X is bonded to a carbon atom in R.) The secondary battery according to claim 1, wherein the nitrile compound represented by Chemical Formula 1 is a compound represented by Chemical Formulas 2 to 4.

(R1 is a monovalent organic group having carbon and at least one of hydrogen and halogen as constituent elements , and X1 is —C (═O) —, —O—C (═O) —, —S ( ═O) —, —O—S (═O) —, —S (═O) ₂ —, or —O—S (═O) ₂ —, wherein X 1 is bonded to the carbon atom in R 1. ing.)

(R 2 is a divalent organic group having carbon and at least one of hydrogen and halogen as constituent elements , and X 2 is —C (═O) —, —O—C (═O) —, —S ( ═O) —, —O—S (═O) —, —S (═O) ₂ —, or —O—S (═O) ₂ —, wherein X 2 is bonded to the carbon atom in R 2. ing.)

(R3 is a (z1 + z2) -valent organic group having carbon and at least one of hydrogen and halogen as constituent elements , and X3 and X4 are -C (= O)-, -O-C (= O)- , —S (═O) —, —O—S (═O) —, —S (═O) ₂ —, or —O—S (═O) ₂ —, and z1 and z2 are integers of 1 or more However, X3 and X4 are different types and they are bonded to the carbon atom in R3.)   The R1 in the chemical formula 2 is an alkyl group having 1 to 10 carbon atoms, an aryl group, a halogenated alkyl group having 1 to 10 carbon atoms, a halogenated aryl group, or a derivative thereof. Secondary battery.   The secondary battery according to claim 2, wherein R 2 in Chemical Formula 3 is an alkylene group having 1 to 3 carbon atoms or a halogenated alkylene group having 1 to 3 carbon atoms. The secondary battery according to claim 1, wherein the content of the nitrile compound shown in Chemical Formula 1 in the non-aqueous solvent is 0.01 wt% or more and 10 wt% or less. The non-aqueous solvent includes a chain carbonate having a halogen represented by Chemical Formula 5, a cyclic carbonate having a halogen represented by Chemical Formula 6, and a cyclic carbonate having an unsaturated bond represented by Chemical Formulas 7 to 9. The secondary battery according to claim 1, comprising at least one of sultone and acid anhydride.

(R11 to R16 are a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, and at least one of them is a halogen group or a halogenated alkyl group.)

(R17 to R20 are a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, and at least one of them is a halogen group or a halogenated alkyl group.)

(R21 and R22 are a hydrogen group or an alkyl group.)

(R23 to R26 are a hydrogen group, an alkyl group, a vinyl group, or an allyl group, and at least one of them is a vinyl group or an allyl group.)

(R27 is an alkylene group.)   The chain carbonate having a halogen shown in Chemical formula 5 is fluoromethyl methyl carbonate, difluoromethyl methyl carbonate or bis (fluoromethyl) carbonate, and the cyclic carbonate having halogen shown in Chemical formula 6 is 4- Fluoro-1,3-dioxolan-2-one or 4,5-difluoro-1,3-dioxolan-2-one, and the cyclic carbonate having an unsaturated bond shown in Chemical Formula 7 is vinylene carbonate The cyclic carbonate having an unsaturated bond shown in Chemical Formula 8 is vinylethylene carbonate, and the cyclic carbonate having an unsaturated bond shown in Chemical Formula 9 is methylene ethylene carbonate. Secondary battery. The electrolytic solution is at least one selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, and compounds represented by chemical formulas 10 to 15. The secondary battery according to claim 1, comprising an electrolyte salt containing

(X31 is a group 1 element or group 2 element in the long-period periodic table, or aluminum (Al). M31 is a transition metal element, or a group 13 element, group 14 element, or group 15 element in the long-period periodic table. R31 is a halogen group, Y31 is — (O═) C—R32—C (═O) —, — (O═) C—C (R33) ₂ — or — (O═) C—C ( ═O) —, wherein R32 is an alkylene group, a halogenated alkylene group, an arylene group or a halogenated arylene group, and R33 is an alkyl group, a halogenated alkyl group, an aryl group or a halogenated aryl group. A3 is an integer of 1 to 4, b3 is 0, 2 or 4, and c3, d3, m3 and n3 are integers of 1 to 3.)

(X41 is a group 1 element or group 2 element in the long periodic table. M41 is a transition metal element, or a group 13, element or group 15 element in the long period periodic table. Y41 is − ( O =) C- (C (R41 ) 2) b4 -C (= O) -, - (R43) 2 C- (C (R42) 2) c4 -C (= O) -, - (R43) 2 C -(C (R42) ₂ ) _c4 -C (R43) ₂ -,-(R43) ₂ C- (C (R42) ₂ ) _c4 -S (= O) ₂ -,-(O =) ₂ S- ( C (R42) ₂ ) _d4- S (= O) _2- or-(O =) C- (C (R42) ₂ ) _d4- S (= O) _2- where R41 and R43 are hydrogen groups. , An alkyl group, a halogen group or a halogenated alkyl group, at least one of each being a halogen group or a halogenated alkyl group. R42 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group, wherein a4, e4 and n4 are 1 or 2, b4 and d4 are integers of 1 to 4, and c4 Is an integer from 0 to 4, and f4 and m4 are integers from 1 to 3.)

(X51 is a group 1 element or group 2 element in the long-period periodic table. M51 is a transition metal element, or a group 13, element or group 15 element in the long-period periodic table. Rf is fluorinated. An alkyl group or a fluorinated aryl group, each having 1 to 10 carbon atoms Y51 is — (O═) C— (C (R51) ₂ ) _d5 —C (═O) —, — (R52); ₂ C- (C (R51) ₂ ) _d5 -C (= O)-,-(R52) ₂ C- (C (R51) ₂ ) _d5 -C (R52) ₂ -,-(R52) ₂ C- ( _{C (R51) 2) d5 -S} (= O) 2 -, - (O =) 2 S- (C (R51) 2) e5 -S (= O) 2 - or - (O =) C- (C _{(R51) 2) e5 -S (} = O) 2 -. is, however, R51 is a hydrogen group, an alkyl group, a halogen group, or a halogen Kaa R52 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group, at least one of which is a halogen group or a halogenated alkyl group, wherein a5, f5 and n5 are 1 or 2; B5, c5 and e5 are integers of 1 to 4, d5 is an integer of 0 to 4, and g5 and m5 are integers of 1 to 3.)

(M and n are integers of 1 or more.)

(R61 is a linear or branched perfluoroalkylene group having 2 to 4 carbon atoms.)

(P, q and r are integers of 1 or more.) The compounds represented by the chemical formula 10 are compounds represented by chemical formulas (1) to (6), and the compounds represented by the chemical formula 11 are represented by chemical formulas (1) to (8). The secondary battery according to claim 8, wherein the compound is a compound, and the compound represented by Chemical Formula 12 is a compound represented by Chemical Formula 18:

  The negative electrode is a negative electrode active material containing a carbon material, lithium metal (Li), or a material that can occlude and release lithium and has at least one of a metal element and a semi-metal element. The secondary battery according to claim 1, further comprising:   2. The negative electrode according to claim 1, wherein the negative electrode includes a negative electrode active material containing a simple substance, an alloy and a compound of silicon (Si), and at least one selected from the group consisting of a simple substance, an alloy and a compound of tin (Sn). Secondary battery.   The negative electrode has a negative electrode active material layer containing a negative electrode active material on a negative electrode current collector, and the negative electrode active material layer is at least one member selected from the group consisting of a vapor phase method, a liquid phase method, and a firing method. The secondary battery according to claim 1, which is formed by a method. The electrolyte solution for secondary batteries containing the nonaqueous solvent containing at least 1 sort (s) of the nitrile compound represented by Chemical formula 19.

(R is a z-valent organic group having carbon and at least one of hydrogen and halogen as constituent elements , and X is —C (═O) —, —O—C (═O) —, —S ( ═O) —, —O—S (═O) —, —S (═O) ₂ —, or —O—S (═O) ₂ —, and z is an integer of 1 or more, where X Is bonded to a carbon atom in R.)   An electronic apparatus comprising the secondary battery according to any one of claims 1 to 12.

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