JP4538753B2 - Electrolyte for lithium ion secondary battery and lithium ion secondary battery - Google Patents

Description

The present invention is a lithium ion secondary battery electrolyte solution containing a solvent, and a lithium ion secondary battery using the same.

  In recent years, portable electronic devices such as a camera-integrated VTR (video tape recorder), a mobile phone, or a laptop computer 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.

As an electrolytic solution for these secondary batteries, a combination of a carbonate ester solvent such as propylene carbonate or diethyl carbonate and an electrolyte salt such as lithium hexafluorophosphate is widely used (for example, Patent Document 1). reference.). This is because the conductivity is high and the potential is stable.
Japanese Patent No. 3294400

In addition, regarding the composition of the electrolytic solution, a technique for incorporating various sulfone compounds into the electrolytic solution has been proposed in order to improve cycle characteristics and storage characteristics. As this sulfone compound, a compound having a sulfonyl fluoride type structure (for example, see Patent Documents 2 to 5), a disulfonic acid anhydride (for example, see Patent Documents 6 to 8), a disulfonic acid ester derivative ( For example, see Patent Documents 9 to 11.).
JP 2002-359001 A JP 2006-049112 A JP 2006-049152 A JP 2006-294519 A JP 2004-022336 A JP 2006-344391 A Japanese Patent No. 3760539 JP 2000-133304 A JP 2006-351337 A JP 2007-080620 A

  In recent years, portable electronic devices have become more sophisticated and multifunctional, and power consumption tends to increase. Accordingly, charging and discharging of secondary batteries used in portable electronic devices 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 the storage characteristics are likely to deteriorate. It is in. 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 the above problems, its object is to provide a cycle characteristics and the storage characteristics can be improved lithium ion secondary battery electrolyte and a lithium ion secondary battery .

Lithium ion secondary battery electrolyte of the present invention, of 1 viewed contains a solvent containing a sulfone compound represented by the content of the sulfone compound shown in Chemical formula 1 in that the solvent is 0.01 wt% or more 10% by weight or less .

The lithium ion secondary battery of the present invention, a cathode and an anode with an electrolyte solution, viewed contains a solvent containing the sulfone compound electrolytic solution shown in Chemical formula 1, containing the sulfone compound shown in Chemical formula 1 in that the solvent The amount is 0.01 wt% or more and 10 wt% or less .

According to the electrolytic solution for a lithium ion secondary battery of the present invention, the solvent contains the sulfone compound shown in Chemical Formula 1 and the content of the sulfone compound shown in Chemical Formula 1 in the solvent is 0.01 wt. % Or more and 10% by weight or less , the chemical stability is improved as compared with the case where it is not contained or when other sulfone compound is contained. Thereby, according to the lithium ion secondary battery provided with the electrolyte solution for lithium ion secondary batteries of this invention, since the decomposition reaction of the electrolyte solution is suppressed, cycling characteristics and storage characteristics can be improved.

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

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

The solvent contains one or more of the sulfone compounds represented by Chemical Formula 3. This is because the chemical stability of the electrolytic solution is improved. The sulfone compound shown in Chemical Formula 3 has a sulfonyl fluoride type structure in which a sulfonyl group (—SO ₂ —) and a fluorine group (—F) are bonded.

（Ｒ１は炭素と水素、酸素およびハロゲンから選択される１種あるいは２種以上の元素とを含んで構成されるｚ価の基であり、スルホニル基中の硫黄原子はＲ１中の炭素原子に結合されている。ｚは２以上の整数である。ただし、Ｒ１が直鎖状のアルキレン基あるいはハロゲン化アルキレン基である場合、それらの炭素数は２以下である。）

(R1 is a z-valent group comprising carbon and one or more elements selected from hydrogen, oxygen and halogen, and the sulfur atom in the sulfonyl group is bonded to the carbon atom in R1. Z is an integer greater than or equal to 2. However, when R1 is a linear alkylene group or a halogenated alkylene group, those carbon number is 2 or less.)

  R1 in Chemical Formula 3 is a group having a carbon chain or carbocycle as a basic skeleton, and in the basic skeleton, any form of one or more elements selected from hydrogen, oxygen, and halogen is present. May be included. The carbon chain may be linear or branched having one or more side chains.

  The above-mentioned “form” means the number of elements, a combination of elements, and the like, which can be arbitrarily set. Specifically, examples of the form of hydrogen include an alkylene group and a part of an arylene group. Examples of the form of oxygen include an ether bond (—O—). Examples of the form of halogen include a part of a halogenated alkylene group. The type of the halogen is not particularly limited, but among them, fluorine is preferable. This is because the chemical stability of the electrolytic solution is higher than that of other halogens. The form of the halogen described above is one in which the hydrogen in R1 is substituted with a halogen. In this case, only a part of hydrogen may be replaced by halogen, or all of hydrogen may be replaced by halogen. Of course, the forms of hydrogen, oxygen and halogen may be other forms than those described above.

  R1 may be any group as long as it has the structure described above, but the sulfur atom in the z sulfonyl groups is bonded to an atom (for example, an oxygen atom) other than a carbon atom in R1. Not necessarily bonded to a carbon atom. Further, when R1 is a linear alkylene group or a halogenated alkylene group, the number of carbon atoms is limited to 2 or less (that is, 1 or 2). This is because the chemical stability of the electrolytic solution is increased and excellent compatibility is obtained as compared with the case where the number of carbon atoms is 3 or more. The “halogenated alkylene group” is a group in which at least a part of hydrogen in an alkylene group is substituted with a halogen.

  R1 may be a derivative of a group constituted by the series of forms described above. In this case, R1 may contain other elements other than hydrogen, oxygen, and halogen as constituent elements. 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.

  As long as it has a structure corresponding to the structure shown in Chemical Formula 3, the sulfone compound may have any structure as a whole, but among them, the compound represented by Chemical Formula 4 is preferable. This is because z (the number of sulfonyl fluoride moieties) can be suppressed to be small, so that high chemical stability can be obtained in the electrolytic solution and excellent compatibility can be obtained. The compound shown in Chemical formula 4 is a compound in which z in Chemical formula 3 is z = 2 and R1 is a divalent group.

（Ｒ２は炭素と水素、酸素およびハロゲンから選択される１種あるいは２種以上の元素とを含んで構成される２価の基であり、スルホニル基中の硫黄原子はＲ２中の炭素原子に結合されている。ただし、Ｒ２が直鎖状のアルキレン基あるいはハロゲン化アルキレン基である場合、それらの炭素数は２以下である。）

(R2 is a divalent group comprising carbon and one or more elements selected from hydrogen, oxygen and halogen, and the sulfur atom in the sulfonyl group is bonded to the carbon atom in R2. (However, when R2 is a linear alkylene group or a halogenated alkylene group, their carbon number is 2 or less.)

  As the divalent group R2, for example, a linear or branched alkylene group, an arylene group, a group in which an arylene group and an alkylene group are bonded, or an alkylene group and an ether bond are bonded. And groups obtained by halogenating them. The “divalent group having an arylene group and an alkylene group” may be a group in which one arylene group and one alkylene group are bonded, or two alkylene groups may be bonded via one arylene group. Or a bonded group. The “group in which an alkylene group and an ether bond 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 number and order of the above-described alkylene group, arylene group or ether bond can be arbitrarily set. Of course, R2 may be a group other than those described above.

  When R2 is a branched alkylene group, the number of carbon atoms can be arbitrarily set, but is preferably 2 or more and 10 or less, more preferably 2 or more and 6 or less, and further preferably 2 or more and 4 or less. When R2 is a group in which an arylene group and an alkylene group are bonded, a group in which two alkylene groups are bonded through one arylene group is preferable. The number of carbons in this case can be arbitrarily set, but 8 is particularly preferable. In any case, high chemical stability can be obtained in the electrolytic solution, and excellent compatibility can be obtained.

When R2 is a group in which an alkylene group and an ether bond are bonded, the number of carbon atoms can be arbitrarily set. Among them, it is preferably 2 or more and 12 or less, more preferably 4 or more and 12 or less. preferable. In this case, in particular, R ₂ is preferably a group represented by —CH ₂ —CH ₂ — (O—CH ₂ —CH ₂ ) _n —, and n is more preferably 1 or more and 3 or less. . This is because high chemical stability can be obtained in the electrolytic solution and excellent compatibility can be obtained.

  Specific examples of R2 include straight-chain alkylene groups represented by chemical formulas (1) and (2) (2 or less carbon atoms) and branches represented by chemical formulas (1) to (9). An alkylene group, an arylene group represented by chemical formulas (1) to (3), a group in which an arylene group represented by chemical formulas (1) to (3) and an alkylene group are bonded, And a group in which an alkylene group represented by chemical formulas (1) to (13) and an ether bond are bonded. In addition, as a group obtained by halogenating the above-described series of groups, a group obtained by halogenating a group in which an alkylene group and an ether bond are bonded as represented by Chemical Formulas (1) to (9) can be given. It is done. Of course, it is not limited to a group in which an alkylene group and an ether bond are bonded, and other alkylene groups and the like may be halogenated.

  Specific examples of the compound shown in Chemical Formula 3 include compounds represented by Chemical Formulas (1) to (5). This is because high chemical stability is obtained in the electrolytic solution, and excellent solubility is also obtained. For confirmation, R1 in Chemical Formula 3 is a linear alkylene group in Chemical Formulas 11 (1) and (2), and a linear fluorinated alkylene in Chemical Formulas 11 (3) and (4). The group is an arylene group in Chemical Formula 11 (5).

  The series of compounds described as the compounds shown in Chemical Formula 3 may be used alone or in combination of two or more. Needless to say, the compound shown in Chemical Formula 3 is not limited to the compounds shown in Chemical Formula 4 and Chemical Formula 11 as long as it has the structure shown in Chemical Formula 3.

  The content of the sulfone compound shown in Chemical Formula 3 in the solvent can be arbitrarily set, 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 amount is less than 0.01% by weight, the chemical stability of the electrolytic solution may not be sufficiently and stably obtained. If the amount is more than 10% by weight, the main electrical properties of the electrochemical device may be decreased. This is because performance (for example, capacity characteristics in a battery) may not be sufficiently obtained.

  This solvent preferably contains any one or more of non-aqueous solvents such as other organic solvents together with the sulfone compound shown in Chemical formula 3. 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, Methyl butyrate, methyl isobutyrate, methyl trimethylacetate, ethyl trimethylacetate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N, N-dimethylformamide, N-methylpyrrolidinone, N -Methyloxazolidinone, N, N'-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, dimethyl sulfoxide, or dimethyl sulfoxide phosphoric acid. Among them, at least one member selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate is preferable. Particularly, a high viscosity (high dielectric constant) solvent such as ethylene carbonate or propylene carbonate (for example, ratio A combination of a dielectric constant ε ≧ 30) and a low viscosity solvent such as dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate (for example, viscosity ≦ 1 mPa · s) is more preferable. This is because the dissociation property of the electrolyte salt and the ion mobility are improved.

  Moreover, the solvent may contain the cyclic carbonate which has an unsaturated bond. This is because the chemical stability of the electrolytic solution is further improved. Examples of the cyclic carbonate having an unsaturated bond include vinylene carbonate compounds, vinyl ethylene carbonate compounds, and methylene ethylene carbonate compounds.

  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-1,3 -Dioxol-2-one or 4-trifluoromethyl-1,3-dioxol-2-one and the like.

  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.

  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-one. And methylene-1,3-dioxolan-2-one.

  These may be used alone or in combination of two or more. Among these, vinylene carbonate is preferable. This is because a high effect can be obtained.

  The solvent may contain at least one of a chain carbonate having a halogen represented by Chemical Formula 12 as a constituent element and a cyclic carbonate having a halogen represented by Chemical Formula 13 as a constituent element. . This is because the chemical stability of the electrolytic solution is further improved.

（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.)

（Ｒ２１〜Ｒ２４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。）

(R21 to R24 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.)

  In addition, R11 to R16 in Chemical formula 12 may be the same as or different from each other. The same applies to R21 to R24 in Chemical formula 13. The “halogenated alkyl group” described for R11 to R16 or R21 to R24 is a group in which at least a part of hydrogen in the alkyl group is substituted with halogen. The type of the halogen is not particularly limited, and examples thereof include at least one selected from the group consisting of fluorine, chlorine and bromine, and among them, fluorine is preferable. This is because a high effect can be obtained. Of course, other halogens may be used.

  In particular, the halogenated carbonate is preferably a compound having two halogens (dihalogenated carbonate) rather than a compound having one halogen (monohalogenated carbonate). This is because a higher effect can be obtained.

  Examples of the chain carbonate having a halogen shown in Chemical formula 12 include fluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, difluoromethyl methyl carbonate, and the like. These may be used alone or in combination of two or more. Of these, bis (fluoromethyl) carbonate is preferred. This is because a high effect can be obtained.

  When at least one of R21 to R24 in Chemical formula 13 is an alkyl group or a halogenated alkyl group, they are preferably a methyl group, an ethyl group, a halogenated methyl group or a halogenated ethyl group. This is because a high effect can be obtained.

  Examples of the cyclic carbonate having a halogen shown in Chemical formula 13 include a series of compounds represented by Chemical formula 14 and Chemical formula 15. That is, 4-fluoro-1,3-dioxolan-2-one of (1) shown in Chemical formula 14, 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-fluoro-5-chloro-1,3-dioxolane-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-methyl-5 of (11) - difluoro-1,3-dioxolane-2-one, 4-ethyl-5,5-difluoro-1,3-dioxolane-2-one (12). Further, 4-trifluoromethyl-5-fluoro-1,3-dioxolan-2-one of (1) shown in Chemical formula 15, 4-trifluoromethyl-5-methyl-1,3-dioxolane of (2) 2-one, 4-fluoro-4,5-dimethyl-1,3-dioxolan-2-one of (3), 4,4-difluoro-5- (1,1-difluoroethyl)-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) , It is a 3-dioxolan-2-one.

  These may be used alone or in combination of two or more. 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. This is because it is easily available and a high effect can be obtained. In particular, 4,5-difluoro-1,3-dioxolan-2-one is preferably a trans isomer rather than a cis isomer.

  Further, the solvent may contain sultone (cyclic sulfonic acid ester) or an acid anhydride. This is because the chemical stability of the electrolytic solution is further improved.

  Examples of sultone include propane sultone and propene sultone. These may be used alone or in combination of two or more. Of these, propene sultone is preferable. Further, the sultone content in the solvent is preferably 0.5% by weight or more and 3% by weight or less. This is because a high effect can be obtained in any case.

  Examples of the acid anhydride include carboxylic acid anhydrides such as succinic anhydride, glutaric anhydride or maleic anhydride, disulfonic anhydrides such as ethanedisulfonic anhydride or propanedisulfonic anhydride, sulfobenzoic anhydride, anhydrous Examples thereof include anhydrides of carboxylic acid and sulfonic acid such as sulfopropionic acid or sulfobutyric anhydride. These may be used alone or in combination of two or more. Of these, anhydrous sulfobenzoic acid is preferable. Moreover, it is preferable that content of the acid anhydride in a solvent is 0.5 to 3 weight%. This is because a high effect can be obtained in any case.

  The intrinsic viscosity of the solvent is preferably 10.0 mPa · s or less at 25 ° C. This is because the dissociation property of the electrolyte salt and the ion mobility are improved. Note that the intrinsic viscosity of the electrolyte salt dissolved in the solvent (so-called intrinsic viscosity of the electrolytic solution) is preferably 10.0 mPa · s or less at 25 ° C. for the same reason.

The electrolyte salt contains, for example, one or more light metal salts such as a lithium salt. As this lithium salt, for example, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium tetraphenylborate (LiB (C ₆ H ₅ ) ₄ ), Lithium methanesulfonate (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). 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 the resistance of the electrolytic solution decreases. In particular, it is preferable to use lithium hexafluorophosphate and lithium tetrafluoroborate in combination. This is because a higher effect can be obtained.

  This electrolyte salt may contain at least one member selected from the group consisting of compounds represented by Chemical formula 16, Chemical formula 17 and Chemical formula 18. This is because a higher effect can be obtained when used together with the above-described lithium hexafluorophosphate or the like. In addition, R33 in Chemical formula 16 may be the same as or different from each other. The same applies to R41 to R43 in Chemical Formula 17 and R51 and R52 in Chemical Formula 18.

（Ｘ３１は短周期型周期表における１Ａ族元素あるいは２Ａ族元素、またはアルミニウムである。Ｍ３１は遷移金属、または短周期型周期表における３Ｂ族元素、４Ｂ族元素あるいは５Ｂ族元素である。Ｒ３１はハロゲン基である。Ｙ３１は−ＯＣ−Ｒ３２−ＣＯ−、−ＯＣ−ＣＲ３３₂ −あるいは−ＯＣ−ＣＯ−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の整数であり、ｃ３、ｄ３、ｍ３およびｎ３は１〜３の整数である。）

(X31 is 1A group element or 2A group element or aluminum in the short period type periodic table. M31 is a transition metal, or 3B group element, 4B group element or 5B group element in the short period type periodic table. R31 is R31. Y31 is —OC—R32—CO—, —OC—CR33 ₂ — or —OC—CO—, wherein 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, wherein a3 is an integer of 1 to 4, b3 is an integer of 0, 2 or 4, c3, d3, m3 and n3 are integers of 1 to 3.)

（Ｘ４１は短周期型周期表における１Ａ族元素あるいは２Ａ族元素である。Ｍ４１は遷移金属、または短周期型周期表における３Ｂ族元素、４Ｂ族元素あるいは５Ｂ族元素である。Ｙ４１は−ＯＣ−（ＣＲ４１₂ ）_b4−ＣＯ−、−Ｒ４３₂ Ｃ−（ＣＲ４２₂ ）_c4−ＣＯ−、−Ｒ４３₂ Ｃ−（ＣＲ４２₂ ）_c4−ＣＲ４３₂ −、−Ｒ４３₂ Ｃ−（ＣＲ４２₂ ）_c4−ＳＯ₂ −、−Ｏ₂ Ｓ−（ＣＲ４２₂ ）_d4−ＳＯ₂ −あるいは−ＯＣ−（ＣＲ４２₂ ）_d4−ＳＯ₂ −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の整数であり、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 1A element or a Group 2A element in the short period type periodic table. M41 is a transition metal, or a Group 3B element, a Group 4B element, or a Group 5B element in the short period type periodic table. Y41 is —OC—. _{(CR41 2) b4 -CO -,} - R43 2 C- (CR42 2) c4 -CO -, - R43 2 C- (CR42 2) c4 -CR43 2 -, - R43 2 C- (CR42 2) c4 -SO ₂ —, —O ₂ S— (CR42 ₂ ) _d4 —SO ₂ — or —OC— (CR42 ₂ ) _d4 —SO ₂ —, wherein R41 and R43 are hydrogen, alkyl, halogen or halogenated An alkyl group, at least one of which is a halogen group or a halogenated alkyl group, and R42 is a hydrogen group, an alkyl group, a halogen group, or a halogenated alkyl group. A4, e4 and n4 are integers of 1 or 2, b4 and d4 are integers of 1 to 4, c4 is an integer of 0 to 4, and f4 and m4 are integers of 1 to 3. )

（Ｘ５１は短周期型周期表における１Ａ族元素あるいは２Ａ族元素である。Ｍ５１は遷移金属、または短周期型周期表における３Ｂ族元素、４Ｂ族元素あるいは５Ｂ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−ＯＣ−（ＣＲ５１₂ ）_d5−ＣＯ−、−Ｒ５２₂ Ｃ−（ＣＲ５１₂ ）_d5−ＣＯ−、−Ｒ５２₂ Ｃ−（ＣＲ５１₂ ）_d5−ＣＲ５２₂ −、−Ｒ５２₂ Ｃ−（ＣＲ５１₂ ）_d5−ＳＯ₂ −、−Ｏ₂ Ｓ−（ＣＲ５１₂ ）_e5−ＳＯ₂ −あるいは−ＯＣ−（ＣＲ５１₂ ）_e5−ＳＯ₂ −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の整数であり、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 1A element or a group 2A element in the short period type periodic table. M51 is a transition metal, or a group 3B element, a group 4B element or a group 5B element in the short period type periodic table. Rf is a fluorinated alkyl. Or a fluorinated aryl group, each having 1 to 10 carbon atoms Y51 is —OC— (CR51 ₂ ) _d5 —CO—, —R52 ₂ C— (CR51 ₂ ) _d5 —CO—, —R52 _{2 C- (CR51 2) d5 -CR52} 2 -, - R52 2 C- (CR51 2) d5 -SO 2 -, - O 2 S- (CR51 2) e5 -SO 2 - or -OC- (CR51 _{2) e5} -SO ₂ -. is, however, R51 is a hydrogen group, an alkyl group, is .R52 is the halogen group or the halogenated alkyl group be a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group At least one of them is a halogen group or a halogenated alkyl group, wherein a5, f5 and n5 are integers of 1 or 2, b5, c5 and e5 are integers of 1 to 4, and d5 is 0 to 0. 4 is an integer, and g5 and m5 are integers of 1 to 3.)

  Examples of the compound represented by Chemical formula 16 include the compounds represented by Chemical formulas (1) to (6). Examples of the compound represented by Chemical formula 17 include the compounds represented by Chemical formulas (1) to (8). Examples of the compound represented by Chemical formula 18 include the compound represented by Chemical formula 21 and the like. Of these, the compounds shown in Chemical Formula 19 (6) or Chemical Formula 20 (6) are preferable. This is because a high effect can be obtained. Needless to say, the compounds shown in Chemical Formulas 16 to 18 are not limited to the compounds shown in Chemical Formulas 19 to 21.

  The electrolyte salt may contain at least one selected from the group consisting of compounds represented by Chemical Formula 22, Chemical Formula 23 and Chemical Formula 24. 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 22 may be the same as or different from each other. The same applies to p, q and r in Chemical Formula 24.

（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２〜４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 22 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 used alone or in combination of two or more.

  Examples of the cyclic compound represented by Chemical Formula 23 include a series of compounds represented by Chemical Formula 25. That is, 1,2-perfluoroethanedisulfonylimide lithium of (1) shown in Chemical Formula 25, 1,3-perfluoropropane disulfonylimide lithium of (2), 1,3-perfluorobutane of (3) Disulfonylimide lithium, 1,4-perfluorobutane disulfonylimide lithium of (4), and the like. These may be used alone or in combination of two or more. Among these, 1,3-perfluoropropane disulfonylimide lithium is preferable. This is because a high effect can be obtained.

Examples of the chain compound shown in Chemical Formula 24 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 sulfone compound shown in Chemical formula 3, it is compared with the case where it does not contain it or the case where it contains another sulfone compound represented by Chemical formula 26. Thus, chemical stability is improved. The other sulfone compound shown in Chemical formula 26 is a compound having 3 carbon atoms when R1 in Chemical formula 3 is a linear alkylene group. Therefore, when used in an electrochemical device such as a battery, the decomposition reaction is suppressed, which can contribute to improvement of cycle characteristics and storage characteristics. In this case, if the sulfone compound shown in Chemical formula 3 is the compound shown in Chemical formula 4 or the content of the sulfone compound shown in Chemical formula 3 in the solvent is 0.01 wt% or more and 10 wt% or less. High effect can be obtained.

  In particular, the solvent is at least one of a cyclic carbonate having an unsaturated bond, a chain carbonate having a halogen shown in Chemical formula 12 and a cyclic carbonate having a halogen shown in Chemical formula 13, sultone, If an acid anhydride is contained, a higher effect can be obtained. In particular, when the solvent contains at least one of a chain carbonate having a halogen shown in Chemical formula 12 and a cyclic carbonate having a halogen shown in Chemical formula 13, it is more dihalogenated than a monohalogenated carbonate. If the carbonate ester is contained, higher effects can be obtained.

  Further, the electrolyte salt is represented by at least one selected from the group consisting of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate and lithium hexafluoroarsenate, and chemical formulas 16 to 18. A higher effect can be obtained if it contains at least one member selected from the group consisting of compounds and at least one member selected from the group consisting of compounds shown in Chemical Formulas 22 to 24.

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

(First battery)
FIG. 1 shows a cross-sectional configuration of the first battery. This battery is, for example, a lithium ion secondary battery in which the capacity of the negative electrode is expressed based on insertion and extraction of lithium which is a battery reactant.

  This secondary battery mainly includes a wound electrode body 20 in which a positive electrode 21 and a negative electrode 22 are wound through a separator 23 inside a substantially hollow cylindrical battery can 11, a pair of insulating plates 12, 13 is stored. The battery can 11 is made of, for example, a metal material such as nickel (Ni) plated iron (Fe), and one end and the other end thereof are closed and opened, respectively. The pair of insulating plates 12 and 13 are arranged so as to extend perpendicular to the winding peripheral surface with the winding electrode body 20 interposed therebetween. The battery structure using the cylindrical battery can 11 is called a cylindrical type.

  A battery lid 14 and a safety valve mechanism 15 and a heat sensitive resistance element (Positive Temperature Coefficient; PTC element) 16 provided on the inside of the battery can 11 are caulked to the open end of the battery can 11 via a gasket 17. 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 this 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 15A is reversed and the electrical connection between the battery lid 14 and the wound electrode body 20 is cut. It has come to be. The heat sensitive resistive element 16 limits the current by increasing the resistance according to the temperature rise, and prevents abnormal heat generation due to a large current. 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 is electrically connected to the battery lid 14, and the negative electrode lead 26 is welded to and electrically connected to the battery can 11.

  FIG. 2 shows an enlarged part of the spirally wound electrode body 20 shown in FIG. 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 occluding and releasing lithium as a positive electrode active material, and a conductive agent, a binder, and the like as necessary. Other materials may be included.

Examples of positive electrode materials capable of inserting and extracting lithium include iron sulfide (FeS ₂ ), titanium sulfide (TiS ₂ ), molybdenum sulfide (MoS ₂ ), niobium selenide (NbSe ₂ ), and vanadium oxide (V Examples thereof include chalcogenides containing no lithium such as ₂ O ₅ ) or lithium-containing compounds containing lithium.

Among these, lithium-containing compounds are preferable because some compounds can obtain a high voltage and a high energy density. Examples of such a lithium-containing compound include a composite oxide containing lithium and a transition metal element, or a phosphate compound containing lithium and a transition metal element. In particular, the lithium-containing compound is made of cobalt, nickel, manganese, and iron. Those containing at least one of the groups are preferred. 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 of the battery, and are generally 0.05 ≦ x ≦ 1.10 and 0.05 ≦ y ≦ 1.10.

Specific 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 a spinel structure Examples thereof include lithium manganese composite oxide (LiMn ₂ O ₄ ). Among these, a composite oxide containing nickel is preferable. This is because a high capacity can be obtained and excellent cycle characteristics can be obtained. Specific examples of the phosphate compound containing lithium and a transition metal element include, for example, a lithium iron phosphate compound (LiFePO ₄ ) or a lithium iron manganese phosphate compound (LiFe _1-u Mn _u PO ₄ (u <1)). Etc.

  In addition, examples of the positive electrode material include oxides such as titanium oxide, vanadium oxide, and manganese dioxide, and conductive polymers such as sulfur, polyaniline, and polythiophene.

  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 preferably made of a metal material having good electrochemical stability, electrical conductivity, and mechanical strength. Examples of the metal material include copper (Cu), nickel, and stainless steel, and copper is particularly preferable. This is because high electrical conductivity can be obtained.

  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 conductive agent, a binder, and the like as necessary. Other materials may be included. Note that the charge capacity of the negative electrode material capable of inserting and extracting lithium is preferably larger than the charge capacity of the positive electrode active material.

  Examples of the negative electrode material capable of inserting and extracting lithium include a carbon material. Examples of such a carbon material include graphitizable carbon, non-graphitizable carbon having a (002) plane spacing of 0.37 nm or more, or graphite having a (002) plane spacing of 0.34 nm or less. Etc. More specifically, there are pyrolytic carbons, cokes, graphites, glassy carbon fibers, fired organic polymer compounds, carbon fibers, activated carbon, carbon blacks, and the like. Among these, coke includes pitch coke, needle coke, petroleum coke, and the like, and 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. A carbon material is preferable because it has a very small change in crystal structure due to insertion and extraction of lithium, so that a high energy density is obtained and an excellent cycle characteristic is obtained, and it also functions as a conductive agent.

  Examples of the negative electrode material capable of occluding and releasing lithium include, for example, a material capable of occluding and releasing lithium and having at least one of a metal element and a metalloid element as a constituent element. Can be mentioned. Such a negative electrode material is preferable because a high energy density is obtained. This negative electrode material may be a single element or an alloy or a compound of a metal element or a metalloid element, or may have at least a part of one or more of these phases. Here, 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. The alloy in the present invention may contain a nonmetallic element. This structure includes a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or a mixture of two or more of them.

  Examples of the metal element or metalloid element constituting the negative electrode material include a metal element or metalloid element capable of forming an alloy with lithium. Specifically, magnesium (Mg), boron (B), aluminum, gallium (Ga), indium (In), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), bismuth (Bi) ), Cadmium (Cd), silver (Ag), zinc (Zn), hafnium (Hf), zirconium (Zr), yttrium (Y), palladium (Pd) or platinum (Pt). Among these, at least one of silicon and tin is 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 at least one selected from the group consisting of a simple substance, an alloy and a compound of silicon, and a simple substance, an alloy and a compound of tin. That is, it is a material having at least a part of a simple substance, an alloy or a compound of silicon, a simple substance, an alloy or a compound of tin, or one or more phases thereof.

  Examples of the silicon alloy include tin, nickel, copper, iron, cobalt (Co), manganese (Mn), zinc, indium, silver, titanium, germanium, bismuth and antimony (second constituent elements other than silicon). Examples include those containing at least one of the group consisting of Sb) and chromium. 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 containing at least 1 sort (s) of these is mentioned.

  Examples of the silicon compound or tin compound include those containing oxygen or carbon, and may contain the second constituent element described above in addition to silicon or tin.

  In particular, as the material having at least one of silicon and tin, a material containing tin as the first constituent element and containing the second and third constituent elements in addition to the tin is preferable. The second constituent element is cobalt, iron, magnesium, titanium, vanadium (V), chromium, manganese, nickel, copper, zinc, gallium, zirconium, niobium (Nb), molybdenum (Mo), silver, indium, cerium ( Ce), 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. This is because the cycle characteristics are improved by including the second and third constituent elements.

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

  This CoSnC-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, or bismuth are preferable, and two or more of them may be included. This is because a higher effect can be obtained.

  The CoSnC-containing material has a phase containing tin, cobalt and carbon, and the phase preferably has a low crystalline structure or an amorphous structure. In the CoSnC-containing material, it is preferable that at least a part of carbon that is a constituent element is bonded to a metal element or a metalloid element that is another constituent element. This is because aggregation or crystallization of tin or the like is suppressed.

  Moreover, as a measuring method for examining the bonding state of elements, for example, X-ray photoelectron spectroscopy (XPS) can be cited. In this XPS, in the apparatus calibrated so that the 4f orbit (Au4f) peak of gold atom is obtained at 84.0 eV, the peak of 1s orbit (C1s) of carbon appears at 284.5 eV in the case of graphite. . 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 carbon is bonded to a metal element or a metalloid element, the peak of C1s appears in a region lower than 284.5 eV. That is, when the peak of the synthetic wave of C1s obtained for the CoSnC-containing material appears in a region lower than 284.5 eV, at least a part of the carbon contained in the CoSnC-containing material is a metal element or a half of other constituent elements. Combined with metal elements.

  In XPS, 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, the C1s peak of the surface-contaminated carbon is set to 284.8 eV, and this is used as an energy standard. In XPS, the waveform of the C1s peak is obtained as a form including the surface contamination carbon peak and the carbon peak in the CoSnC-containing material. For example, by analyzing using commercially available software, the surface contamination The carbon peak and the carbon peak in the CoSnC-containing material are separated. 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).

  Furthermore, examples of the negative electrode material capable of inserting and extracting lithium include metal oxides and polymer compounds capable of inserting and extracting 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, you may use combining the negative electrode material which can occlude and discharge | release the above-mentioned series of lithium.

  Examples of the conductive agent include carbon materials such as graphite, carbon black, and ketjen black. These may be used alone or in combination of two or more. Note that the conductive agent may be a metal material or a conductive polymer as long as it is a conductive material.

  Examples of the binder include synthetic rubbers such as styrene butadiene rubber, fluorine rubber or ethylene propylene diene, and polymer materials such as polyvinylidene fluoride. These may be used alone or in combination of two or more. However, as shown in FIG. 1, when the positive electrode 21 and the negative electrode 22 are wound, it is preferable to use a styrene butadiene rubber or a fluorine rubber having high flexibility.

  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 due to contact between both electrodes. The separator 23 is made of, for example, a porous film made of a synthetic resin made of polytetrafluoroethylene, polypropylene, polyethylene, or the like, or a porous film made of ceramic, and these two or more kinds of porous films are laminated. You may have the structure made. Among them, a porous film made of polyolefin is preferable because it is excellent in short-circuit preventing effect and can improve battery safety by a shutdown effect. In particular, polyethylene is preferable because a shutdown effect can be obtained at 100 ° C. or higher and 160 ° C. or lower and the electrochemical stability is excellent. Polypropylene is also preferable, and other resins having chemical stability may be copolymerized with polyethylene or polypropylene, or may be blended.

  The separator 23 is impregnated with the above-described electrolytic solution as a liquid electrolyte. This is because the cycle characteristics are improved.

  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. On the other hand, when discharging is performed, for example, lithium ions are extracted from the negative electrode 22 and inserted in the positive electrode 21 through the electrolytic solution.

  This secondary battery is manufactured as follows, for example.

  First, for example, the positive electrode active material layer 21B is formed on both surfaces of the positive electrode current collector 21A to produce the positive electrode 21. In this case, a positive electrode mixture in which a positive electrode active material, a conductive agent, and a binder are mixed is dispersed in a solvent to form a paste-like positive electrode mixture slurry, and the positive electrode mixture slurry is used as the positive electrode current collector 21A. After coating and drying, the positive electrode active material layer 21B is formed by compression molding with a roll press. For example, the negative electrode 22 is manufactured by forming the negative electrode active material layer 22B on both surfaces of the negative electrode current collector 22A by the same manufacturing procedure as that of the positive electrode 21.

  Subsequently, 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, the positive electrode 21 and the negative electrode 22 are wound through the separator 23 to form the wound electrode body 20, and 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 connected to the battery. After welding to the can 11, the wound electrode body 20 is housed inside the battery can 11 while being sandwiched between the pair of insulating plates 12 and 13. Subsequently, an electrolyte salt is dissolved in a solvent containing the sulfone compound shown in Chemical Formula 3 to prepare an electrolytic solution, and then the electrolytic solution 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 caulked and fixed to the opening end of the battery can 11 via the gasket 17. Thereby, the secondary battery shown in FIGS. 1 and 2 is completed.

  According to this cylindrical secondary battery, when the capacity of the negative electrode 22 is expressed based on insertion and extraction of lithium, since the above-described electrolytic solution is provided, the decomposition reaction of the electrolytic solution is suppressed. . Therefore, cycle characteristics and storage characteristics can be improved. In particular, if the negative electrode active material of the negative electrode 22 is capable of inserting and extracting lithium and contains a material having at least one of a metal element and a metalloid element as a constituent element, the electrolyte solution is more Since it becomes easy to decompose | disassemble, a higher effect than the case where a carbon material is contained can be acquired. Other effects relating to the secondary battery are the same as those described for the above-described electrolytic solution.

  Next, the second and third batteries will be described. Components that are the same as those of the first battery are denoted by the same reference numerals, and description thereof is omitted.

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

  The negative electrode 22 has a negative electrode active material layer 22B provided on both surfaces of a negative electrode current collector 22A, as in the first 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, it contains a silicon simple substance, an alloy or a compound, or a tin simple substance, an alloy or a compound, and may contain two or more of them.

  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, the constituent element of the negative electrode current collector 22A may be diffused into the negative electrode active material layer 22B at the interface, or the constituent element of the negative electrode active material layer 22B may be diffused 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 vapor deposition method, sputtering method, ion plating method, laser ablation method, thermal chemical vapor deposition (CVD; Chemical Vapor Deposition) Or plasma chemical vapor deposition. 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 battery)
The third battery is a lithium metal secondary battery in which the capacity of the negative electrode 22 is expressed based on the precipitation and dissolution of lithium. This secondary battery has the same configuration as that of the first 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 released from the positive electrode 21 and deposited as lithium metal on the surface of the negative electrode current collector 22A through the electrolytic solution. On the other hand, when discharging is performed, for example, lithium metal is eluted from the negative electrode active material layer 22B as lithium ions and inserted into the positive electrode 21 through the electrolytic solution.

  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 battery described above.

(4th battery)
FIG. 3 illustrates an exploded perspective configuration of the fourth battery. In this battery, a wound electrode body 30 to which a positive electrode lead 31 and a negative electrode lead 32 are attached is mainly housed in a film-shaped exterior member 40. 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 each 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. The negative electrode lead 32 is made of a metal material such as copper, nickel, or stainless steel, for example. Each metal material which comprises the positive electrode lead 31 and the negative electrode lead 32 is made into thin plate shape or mesh shape, for example.

  The exterior member 40 is made of, for example, a rectangular aluminum laminated film in which a nylon film, an aluminum foil, and a polyethylene film are bonded together in this order. In the exterior member 40, for example, a polyethylene film is opposed to the spirally wound electrode body 30, and each outer edge portion is in close contact with each other by fusion or an adhesive. 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, for example, a polyolefin resin such as polyethylene, polypropylene, modified polyethylene, or modified polypropylene.

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

  FIG. 4 shows a cross-sectional configuration along line IV-IV of the spirally wound electrode body 30 shown in FIG. The electrode winding body 30 is obtained by winding a positive electrode 33 and a negative electrode 34 after being laminated 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 configurations 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 are the same as the positive electrode current collector 21A and the positive electrode active material in the first to third batteries described above. The configurations of the layer 21B, the negative electrode current collector 22A, the negative electrode active material layer 22B, and the separator 23 are the same.

  The electrolyte 36 includes the above-described electrolytic solution and a polymer compound that holds the electrolytic solution, and is in a so-called gel form. A 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.

  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 used alone or in combination of two or more. In particular, from the viewpoint of electrochemical stability, polyacrylonitrile, polyvinylidene fluoride, polyhexafluoropropylene, polyethylene oxide, and the like are preferable. The addition amount of the polymer compound in the electrolytic solution varies depending on the compatibility between the two, but is preferably 5% by mass or more and 50% by mass or less.

  The composition of the electrolytic solution is the same as the composition of the electrolytic solution in the first battery described above. However, the term “solvent” as used herein is a broad concept including not only a liquid solvent but also one having ion conductivity capable of dissociating an electrolyte salt. Accordingly, when a polymer compound having ion conductivity is used, the polymer compound is also included in the solvent. In particular, when a liquid solvent is used, it is preferable to use propylene carbonate. This is because swelling of the secondary battery is suppressed.

  Instead of the 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 by, for example, the same procedure as in the first battery manufacturing method, and the positive electrode 33 is manufactured. A negative electrode active material layer 34B is formed on both sides of the current collector 34A to produce a negative electrode 34. Subsequently, a precursor solution containing the above-described electrolytic solution, a polymer compound, and a solvent is prepared and applied to the positive electrode 33 and the negative electrode 34, and then the solvent is volatilized to form the gel electrolyte 36. Subsequently, the positive electrode lead 31 and the negative electrode lead 32 are attached to the positive electrode current collector 33A and the negative electrode current collector 34A, respectively. 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 periphery thereof to form 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 that 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. 3 and 4 is completed.

  In the second manufacturing method, first, the positive electrode lead 31 and the negative electrode lead 32 are attached to the positive electrode 33 and the negative electrode 34, respectively, and then the positive electrode 33 and the negative electrode 34 are stacked and wound via the separator 35, and the outermost periphery is wound. A protective tape 37 is adhered to the part to form a wound body that is a precursor of the wound electrode body 30. Subsequently, after sandwiching the wound body between the two film-like exterior members 40, the remaining outer peripheral edge portion excluding the outer peripheral edge portion on one side is bonded by thermal fusion or the like to form a bag-like exterior member The wound body is accommodated inside 40. Subsequently, an electrolyte composition containing the above-described 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-like shape. After pouring into the exterior member 40, the opening 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 first 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, a binary copolymer containing vinylidene fluoride and hexafluoropropylene as components, and a ternary copolymer 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.

  The operations and effects of the laminate film type secondary battery are the same as those of the first to third batteries.

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

(Example 1-1)
Using artificial graphite as the negative electrode active material, the laminate film type secondary battery shown in FIGS. 3 and 4 was produced. 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, 91 parts by mass of lithium cobalt composite oxide as a positive electrode active material, 6 parts by mass of graphite as a conductive agent, and 3 parts by mass of polyvinylidene fluoride as a binder were mixed to form a positive electrode mixture. Dispersed in methyl-2-pyrrolidone to obtain a paste-like positive electrode mixture slurry. Finally, the positive electrode mixture slurry is uniformly applied to both surfaces of the positive electrode current collector 33A made of a strip-shaped aluminum foil (20 μm thick) and dried, and then the positive electrode active material layer 33B is formed by compression molding with a roll press. Formed.

  Next, the negative electrode 34 was produced. First, 90 parts by mass of artificial graphite as a negative electrode active material and 10 parts by mass of polyvinylidene fluoride as a binder were mixed to form a negative electrode mixture, which was then dispersed in N-methyl-2-pyrrolidone and pasty. A negative electrode mixture slurry was obtained. Finally, the negative electrode mixture slurry was uniformly applied to both surfaces of the negative electrode current collector 34A made of a strip-shaped copper foil (15 μm thick), dried, and then compression-molded with a roll press to form the negative electrode active material layer 34B. Formed.

Next, an electrolytic solution was prepared. First, as a solvent, ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a weight ratio of EC: DEC = 30: 70, and then the sulfone compound shown in Chemical formula 3 (compound shown in Chemical formula 4) was used. A compound of chemical formula 11 (2) was added and mixed. Under the present circumstances, content of the compound of Chemical formula 11 (2) in the solvent was 0.01 weight%. This “% by weight” is a unit when the entire solvent is 100% by weight, and the same applies hereinafter. Finally, lithium hexafluorophosphate (LiPF ₆ ) was dissolved in the solvent as an electrolyte salt. At this time, the concentration of the electrolyte salt in the electrolytic solution was set to 1 mol / kg.

  Next, a secondary battery was assembled using 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, the positive electrode 33, the separator 35 (thickness 25 μm) made of a microporous polypropylene film, and the negative electrode 34 are laminated in this order and wound in the longitudinal direction many times, and then the protective tape 37 made of an adhesive tape is used. The winding end part was fixed, and the wound body which is the precursor of the wound electrode body 30 was formed. Subsequently, an exterior member made of a laminate film having a three-layer structure (total thickness of 100 μm) in which a nylon film (30 μm thickness), an aluminum foil (40 μm thickness), and an unstretched polypropylene film (30 μm thickness) are laminated from the outside. After sandwiching the wound body between 40, the outer edge portions except for one side were heat-sealed to accommodate the wound body in the bag-shaped exterior member 40. Subsequently, an electrolytic solution was injected into the inside through the opening of the exterior member 40 and the separator 35 was impregnated with the electrolytic solution to form 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.

(Examples 1-2 to 1-5)
The content of the compound of Chemical Formula 11 (2) in the solvent is 1 wt% (Example 1-2), 2 wt% (Example 1-3), 5 wt% (Example 1-4), or 10 wt%. % (Example 1-5), except that the procedure was the same as Example 1-1.

(Examples 1-6 to 1-9)
In place of the compound of formula 11 (2), the compound of formula 11 (1) (Example 1-6), the compound of formula 11 (3) (Example 1-7), the compound of formula 11 (4) (implementation) The same procedure as in Example 1-2 was performed, except that the compound of Example 1-8) or the chemical formula 11 (5) (Example 1-9) was used.

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

(Comparative Example 1-2)
A procedure similar to that of Example 1-2 was performed except that another sulfone compound represented by Chemical Formula 26 was used instead of the sulfone compound represented by Chemical Formula 3.

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

  When investigating cycle characteristics, charge and discharge for 2 cycles in an atmosphere at 23 ° C. to measure discharge capacity, and then repeatedly charge and discharge in the same atmosphere until the total number of cycles reaches 100 cycles to measure discharge capacity. Then, normal temperature cycle discharge capacity maintenance rate (%) = (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 investigating the storage characteristics, charge and discharge for 2 cycles in an atmosphere at 23 ° C., measure the discharge capacity, and then store again in an 80 ° C. thermostatic bath for 10 days in a recharged state. After discharging in the medium and measuring the discharge capacity, the 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 Examples 1-1 to 1-9 in which the solvent contains the sulfone compound shown in Chemical Formula 3 (compounds of Chemical Formulas 11 (1) to (5)), Comparative Examples not containing them The room temperature cycle discharge capacity retention rate and the high temperature storage discharge capacity retention rate higher than those of 1-1 and 1-2 were obtained.

  Specifically, in Examples 1-1 to 1-5 in which the solvent contains the compound of Chemical Formula 11 (2), compared with Comparative Example 1-1 that does not contain the compound, normal temperature cycle discharge capacity retention rate and high-temperature storage The discharge maintenance rate increased. In this case, when the content of the compound of chemical formula 11 (2) in the solvent is 0.01 wt% or more and 10 wt% or more, a high normal temperature cycle discharge capacity maintenance ratio and a high temperature storage discharge capacity maintenance ratio can be obtained. It was. When the content of the compound of Chemical Formula 11 (2) is less than 0.01% by weight or more than 10% by weight, the normal temperature cycle discharge capacity maintenance rate and the high temperature storage discharge capacity maintenance rate are significantly reduced, exceeding 10% by weight. However, the capacity also showed a tendency to decrease significantly.

  Further, in Examples 1-6 to 1-9 in which the solvent contains a compound such as Chemical Formula 11 (1), the normal temperature cycle discharge capacity retention rate and the high-temperature storage discharge capacity are compared with Comparative Example 1-1 in which the solvent is not contained. The retention rate increased, and a room temperature cycle discharge capacity retention rate and a high-temperature storage discharge capacity retention rate substantially equivalent to those of Example 1-2 containing the compound of formula 11 (2) were obtained.

  In particular, Examples containing the sulfone compounds (compounds of Formulas 11 (1) and (2)) shown in Chemical Formula 3 on the basis of the normal temperature cycle discharge capacity retention rate and high-temperature storage discharge capacity retention rate of Comparative Example 1-1 When compared with 1-2, 1-6 and Comparative Example 1-2 containing the other sulfone compound shown in Chemical Formula 26, the room temperature cycle discharge capacity retention rate and the high temperature storage discharge capacity retention rate were slightly lower in the latter case. Only increased, but increased significantly in the former. This result shows that the sulfone compound shown in Chemical formula 3 and the other sulfone compound shown in Chemical formula 26 are common in that R1 in Chemical formula 3 is a linear alkylene group. This indicates that the former (carbon number 2 or less) is overwhelmingly advantageous over the latter (carbon number 3) in increasing the maintenance rate and the high-temperature storage discharge capacity maintenance rate. This tendency is the same when R1 is a linear halogenated alkylene group.

  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 contains the sulfone compound shown in Chemical Formula 3, whereby cycle characteristics and storage characteristics are obtained. Has been confirmed to improve. Further, when R1 in Chemical Formula 3 is a linear alkylene group or a halogenated alkylene group, it was confirmed that excellent characteristics can be obtained when the carbon number is 2 or less. In this case, if the content of the compound shown in Chemical Formula 3 in the solvent is 0.01% by weight or more and 10% by weight or less, good characteristics are obtained, and if the content is 1% by weight or more and 5% by weight or less, the characteristics are obtained. It has also been confirmed that

(Example 2-1)
The same procedure as in Example 1-2 was performed except that propylene carbonate (PC) was added as a solvent. At this time, the mixing ratio of EC, DEC, and PC was 20:60:20 by weight.

(Examples 2-2 and 2-3)
A procedure similar to that of Example 1-2 was performed except that ethylmethyl carbonate (EMC: Example 2-2) or dimethyl carbonate (DMC: Example 2-3) was used instead of DEC as a solvent. .

(Examples 2-4 to 2-10)
As a solvent, vinylene carbonate (VC: Example 2-4) which is a cyclic carbonate having an unsaturated bond, and 4-fluoro-1,3-dioxolane-2-2 which is a cyclic carbonate having a halogen shown in Chemical formula 13 are used. ON (FEC: Example 2-5), trans-4,5-difluoro-1,3-dioxolan-2-one (t-DFEC: Example 2-6), cis-4,5-difluoro-1, 3-dioxolan-2-one (c-DFEC: Example 2-7), bis (fluoromethyl) carbonate (BFDMC: Example 2-8), which is a chain carbonate having a halogen shown in Chemical formula 12, Sultone Propensultone (PRS: Example 2-9) or acid anhydride, sulfobenzoic anhydride (SBAH: Example 2-10), was added, but the same procedure as in Example 1-2 Through was. At this time, the content of VC or the like in the solvent was 1% by weight.

(Comparative Examples 2-1 and 2-2)
The same procedure as in Examples 2-5 and 2-6 was performed, except that the compound of Chemical Formula 11 (2) was not added.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 2-1 to 2-10 and Comparative Examples 2-1 and 2-2 were examined, the results shown in Table 2 were obtained.

  As shown in Table 2, in Examples 2-1 to 2-3 in which the solvent contains the compound of Chemical Formula 11 (2) and also contains PC and the like, Comparative Example 1 not containing the compound of Chemical Formula 11 (2) The normal temperature cycle discharge capacity maintenance rate and the high temperature storage discharge maintenance rate are higher than those of -1, and the normal temperature cycle discharge capacity maintenance rate and the high temperature storage discharge capacity maintenance rate almost the same as those of Example 1-2 not containing PC or the like are obtained. It was.

  Moreover, in Examples 2-4 to 2-10 in which the solvent contains VC or the like, the normal temperature cycle discharge capacity maintenance rate is much higher than that in Example 1-2 not containing them, and the high-temperature storage discharge maintenance rate is equal to or higher than that. Became. In this case, when compared between FEC, t-DFEC and c-DFEC, in the case of containing t-DFEC or the like which is a dihalogenated carbonate rather than the case of containing FEC which is a monohalogenated carbonate, The normal temperature cycle discharge capacity maintenance rate and the high temperature storage discharge maintenance rate tended to increase. Of course, in Examples 2-5 and 2-6 in which the solvent contains the compound of Chemical Formula 11 (2), the normal temperature cycle discharge capacity retention rate and the high-temperature storage discharge are higher than those in Comparative Examples 2-1 and 2-2 that do not contain the compound. The maintenance rate became high.

  From these results, it was confirmed that in the secondary battery of the present invention described above, the cycle characteristics and the storage characteristics were improved even when the composition of the solvent was changed. In this case, even when propylene carbonate or the like is added to the solvent, high characteristics are obtained, and the cyclic carbonate having an unsaturated bond in the solvent, the chain carbonate having a halogen shown in Chemical Formula 12, and Chemical Formula 13 are used. It was also confirmed that the properties were further improved by adding at least one of the above-mentioned cyclic carbonates having halogen, sultone, or acid anhydride.

(Examples 3-1 to 3-3)
Lithium tetrafluoroborate (LiBF ₄ : Example 3-1) as an electrolyte salt, a compound represented by Chemical Formula 19 (6) (Example 3-2) or a compound represented by Chemical Formula 17 The same procedure as in Example 1-2 was performed except that the compound of Example 20 (6) (Example 3-3) was added. At this time, the concentration of lithium hexafluorophosphate in the electrolyte was 0.9 mol / kg, and the concentration of lithium tetrafluoroborate and the like was 0.1 mol / kg.

  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 electrolyte salt contains lithium tetrafluoroborate and the like, the normal temperature cycle discharge capacity maintenance rate and The high-temperature storage discharge maintenance rate increased.

  From this, it was confirmed that in the secondary battery of the present invention described above, the cycle characteristics and the storage characteristics are improved even if the type of the electrolyte salt is changed. In this case, it was confirmed that the characteristics were further improved if the electrolyte salt contained lithium tetrafluoroborate, the compound shown in Chemical formula 16 or the compound shown in Chemical formula 17.

  Here, the electrolyte salt is at least one selected from the group consisting of lithium perchlorate and lithium hexafluoroarsenate, the compound shown in Chemical formula 18, and the group consisting of compounds shown in Chemical formulas 22-24. Although the results in the case of containing at least one kind of lithium perchlorate have the same function as lithium tetrafluoroborate etc., the same is true when lithium perchlorate etc. is contained. It is clear that the result is obtained. The same applies to the case where two or more kinds of the above-described electrolyte salts are mixed between the same or different types.

(Examples 4-1 to 4-5)
A procedure similar to that of Examples 1-1 to 1-5 was performed except that the negative electrode active material layer 34B was formed using silicon instead of artificial graphite as the negative electrode active material. In forming this negative electrode active material layer 34B, silicon was deposited on the negative electrode current collector 34A by electron beam evaporation.

(Examples 4-6 to 4-9)
In place of the compound of formula 11 (2), the compound of formula 11 (1) (Example 4-6), the compound of formula 11 (3) (Example 4-7), the compound of formula 11 (4) (implementation) The same procedure as in Example 4-3 was performed, except that the compound of Example 4-8) or chemical formula 17 (5) (Example 4-9) was used.

(Comparative Examples 4-1 and 4-2)
Similar to Examples 4-1 to 4-9, the same procedure as in Comparative Examples 1-1 and 1-2 was performed, except that the negative electrode active material layer 34B was formed using silicon as the negative electrode active material.

  When the cycle characteristics and the storage characteristics of the secondary batteries of Examples 4-1 to 4-9 and Comparative examples 4-1 and 4-2 were examined, the results shown in Table 4 were obtained.

  As shown in Table 4, even when silicon was used as the negative electrode active material, the same results as those shown in Table 1 were obtained. That is, in Examples 4-1 to 4-5 in which the solvent contains the compound of Chemical Formula 11 (2), the room temperature cycle discharge capacity retention rate and high-temperature storage are higher than those of Comparative Examples 4-1 and 4-2 not containing them. In Examples 4-6 to 4-9 in which the discharge capacity retention ratio was obtained and the solvent contained a compound such as Chemical Formula 11 (1), Example 4-3 containing a compound of Chemical Formula 11 (2) and Almost the same room temperature cycle discharge capacity maintenance rate and high temperature storage discharge capacity maintenance rate were obtained. In this case, when the content of the compound of chemical formula 11 (2) in the solvent is 0.01 wt% or more and 10 wt% or more, a high normal temperature cycle discharge capacity maintenance ratio and a high temperature storage discharge capacity maintenance ratio can be obtained. It was.

  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 contains the sulfone compound shown in Chemical Formula 3, thereby providing cycle characteristics and storage characteristics. It was confirmed to improve. In this case, if the content of the compound shown in Chemical Formula 3 in the solvent is 0.01% by weight or more and 10% by weight or less, good characteristics are obtained, and if the content is 1% by weight or more and 10% by weight or less, the characteristics are obtained. It has also been confirmed that

(Example 5-1)
The same procedure as in Example 4-3 was performed, except that PC was added as a solvent. At this time, the mixing ratio of EC, DEC, and PC was 20:60:20 by weight.

(Examples 5-2 and 5-3)
A procedure similar to that in Example 4-3 was performed except that EMC (Example 5-2) or DMC (Example 5-3) was used instead of DEC as a solvent.

(Example 5-4)
The same procedure as in Example 4-3 was performed except that FEC was used instead of EC as a solvent.

(Examples 5-5 to 5-11)
VC (Example 5-5), FEC (Example 5-6), t-DFEC (Example 5-7), c-DFEC (Example 5-8), BFDMC (Example 5-9) as solvents , PRS (Example 5-10) or SBAH (Example 5-11) was added, and the same procedure as in Example 4-2 was performed. At this time, the content of VC or the like in the solvent was 5% by weight.

(Comparative Examples 5-1 to 5-4)
The same procedure as in Examples 5-4 to 5-7 was performed, except that the compound of Chemical Formula 11 (2) was not added.

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

  As shown in Table 5, when silicon was used as the negative electrode active material, the same results as those shown in Table 2 were obtained. That is, in Examples 5-1 to 5-4 in which the solvent contains the compound of Chemical Formula 11 (2) and also contains PC and the like, the cycle at room temperature is higher than that of Comparative Example 4-1 that does not contain the compound of Chemical Formula 11 (2). The discharge capacity maintenance rate and the high temperature storage discharge capacity maintenance rate were increased, and a room temperature cycle discharge capacity maintenance rate and a high temperature storage discharge capacity maintenance rate almost equal to or higher than those of Example 4-3 not containing PC or the like were obtained. Further, in Examples 5-5 to 5-11 in which the solvent contains VC or the like, the normal temperature cycle discharge capacity retention rate is higher than that in Example 4-2 not containing them, and the high-temperature storage discharge capacity maintenance rate is almost the same. It became equal or better. In particular, when t-DFEC or the like which is a dihalogenated carbonate is contained than when FEC which is a monohalogenated carbonate is contained, the room temperature cycle discharge capacity maintenance rate and the high-temperature storage discharge capacity maintenance rate tend to be higher. Indicated.

  From these results, it was confirmed that in the secondary battery of the present invention described above, the cycle characteristics and the storage characteristics were improved even when the composition of the solvent was changed. In this case, even when propylene carbonate or the like is added to the solvent, high characteristics are obtained, and the cyclic carbonate having an unsaturated bond in the solvent, the chain carbonate having a halogen shown in Chemical Formula 12, and Chemical Formula 13 are used. It was also confirmed that the properties were further improved by adding at least one of the above-mentioned cyclic carbonates having halogen, sultone, or acid anhydride.

(Examples 6-1 to 6-3)
Except for adding LiBF ₄ (Example 6-1), a compound of Chemical Formula 19 (6) (Example 6-2), or a compound of Chemical Formula 20 (6) (Example 6-3) as an electrolyte salt, The same procedure as in Example 4-3 was performed. At this time, the concentration of lithium hexafluorophosphate in the electrolyte was 0.9 mol / kg, and the concentration of lithium tetrafluoroborate and the like was 0.1 mol / kg.

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

  As shown in Table 6, the same results as those shown in Table 3 were obtained when silicon was used as the negative electrode active material. That is, in Examples 6-1 to 6-3 in which the electrolyte salt contains lithium tetrafluoroborate and the like, the normal temperature cycle discharge capacity retention rate and the high-temperature storage discharge capacity retention rate are higher than those in Example 4-3 not containing them. Became high.

  From this, it was confirmed that in the secondary battery of the present invention described above, the cycle characteristics and the storage characteristics are improved even if the type of the electrolyte salt is changed. In this case, it was confirmed that the characteristics were further improved if the electrolyte salt contained lithium tetrafluoroborate, the compound shown in Chemical formula 16 or the compound shown in Chemical formula 17.

  From the results shown in Tables 1 to 6, in the secondary battery of the present invention, the solvent of the electrolytic solution contains the sulfone compound shown in Chemical Formula 3, regardless of the type of the negative electrode active material and the composition of the solvent. It was confirmed that cycle characteristics and storage characteristics were improved. In this case, silicon (a material that can occlude and release lithium and has at least one of a metal element and a metalloid element) is used as compared with a case where a carbon material is used as the negative electrode active material. In this case, since the increase rate of the discharge capacity retention rate was increased, it was confirmed that a higher effect was obtained in the latter 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 .

Further, in the above-described embodiments and examples, the case where the electrolytic solution or the gel electrolyte in which the electrolytic solution is held in the polymer compound is used as the electrolyte of the lithium ion secondary battery of the present invention has been described. These types of electrolytes may be used. Other electrolytes include, for example, a mixture of an ion conductive inorganic compound such as ion conductive ceramics, ion conductive glass or ionic crystal and an electrolyte, or a mixture of another inorganic compound and an electrolyte. Or a mixture of these inorganic compounds and a gel electrolyte.

In the above-described embodiments and examples, as the lithium ion secondary battery of the present invention, when the capacity of the negative electrode is expressed based on insertion and extraction of lithium ions, the capacity of the negative electrode is Although the case where it represents based on melt | dissolution was demonstrated, it is not necessarily restricted to this. The lithium ion secondary battery of the present invention has a negative electrode capacity based on insertion and extraction of lithium ions by making the charge capacity of the negative electrode material capable of inserting and extracting lithium ions smaller than the charge capacity of the positive electrode. The same applies to a case that includes a capacity and a capacity based on precipitation and dissolution of lithium metal and is expressed by the sum of the capacities.

In the above-described embodiments or examples, the lithium ion secondary battery of the present invention is exemplified by the case where the battery structure is a cylindrical type and the laminate film type, and the case where the battery element has a winding structure. As described above, the present invention can be similarly applied to a case where other battery structures such as a square shape, a coin shape, or a button shape are provided, and a case where the battery element has another structure such as a laminated structure.

Moreover, in the said embodiment and Example, about the content of the sulfone compound shown to Chemical formula 3 in the electrolyte solution for lithium ion secondary batteries of this invention or a lithium ion secondary battery, the appropriateness derived from the result of the Example Although the range is described, the description 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 battery using 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. It is a disassembled perspective view showing the structure of the 4th battery using the electrolyte solution which concerns on one embodiment of this invention. It is sectional drawing showing the structure along the IV-IV line of the wound electrode body shown in FIG.

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 ... adhesion film.

Claims (17)

A cathode and an anode with an electrolyte solution, the electrolyte solution saw contains a solvent containing a sulfone compound represented by Formula 1, the content of the sulfone compound shown in the Formula 1 in the solvent is 0.01 wt% A lithium ion secondary battery having a content of 10% by weight or less .

The solvent contains at least one of cyclic ester carbonate having halogen represented by chain carbonic ester and of 4 with a halogen represented by Chemical Formula 3, claim 1 lithium ion secondary battery according .

(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.)

(R21 to R24 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.) 3. The lithium ion secondary battery according to claim 2 , wherein the chain carbonate having halogen shown in Chemical Formula 3 and the cyclic carbonate having halogen shown in Chemical Formula 4 are compounds having one halogen. 4. The chain carbonate having halogen shown in Chemical Formula 3 is fluoromethyl methyl carbonate, and the cyclic carbonate having halogen shown in Chemical Formula 4 is 4-fluoro-1,3-dioxolan-2-one. there, the lithium ion secondary battery according to claim 3, wherein. 3. The lithium ion secondary battery according to claim 2 , wherein the chain carbonate having a halogen shown in Chemical Formula 3 and the cyclic carbonate having a halogen shown in Chemical Formula 4 are compounds having two halogens. The chain carbonate having halogen shown in Chemical Formula 3 is bis (fluoromethyl) carbonate, and the cyclic carbonate having halogen shown in Chemical Formula 4 is 4,5-difluoro-1,3-dioxolane- The lithium ion secondary battery according to claim 5 , which is 2-one. The solvent contains a cyclic ester carbonate having an unsaturated bond, a lithium ion secondary battery according to claim 1, wherein. The solvent contains sultone, the lithium ion secondary battery according to claim 1, wherein. The solvent contains an acid anhydride, a lithium ion secondary battery according to claim 1, wherein. Contains at least one of lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium perchlorate (LiClO ₄ ), and lithium hexafluoroarsenate (LiAsF ₆ ) The lithium ion secondary battery according to claim 1, comprising an electrolyte salt. Of 5, it is including at least one electrolyte salt containing lithium ion secondary battery according to claim 1, wherein one of the compounds represented by Formula 6 and Formula 7.

(X31 is a 1A group element or 2A group element or aluminum (Al) in the short period type periodic table. M31 is a transition metal, or a 3B group element, 4B group element or 5B group element in the short period type periodic table. R31 is a halogen group, Y31 is —OC—R32—CO—, —OC—CR33 ₂ — or —OC—CO—, wherein R32 is an alkylene group, a halogenated alkylene group, an arylene group or a halogenated group. R33 is an alkyl group, a halogenated alkyl group, an aryl group or a halogenated aryl group, wherein a3 is an integer of 1 to 4, b3 is an integer of 0, 2 or 4, and c3 , D3, m3 and n3 are integers of 1 to 3.)

(X41 is a Group 1A element or a Group 2A element in the short period type periodic table. M41 is a transition metal, or a Group 3B element, a Group 4B element, or a Group 5B element in the short period type periodic table. Y41 is —OC—. _{(CR41 2) b4 -CO -,} - R43 2 C- (CR42 2) c4 -CO -, - R43 2 C- (CR42 2) c4 -CR43 2 -, - R43 2 C- (CR42 2) c4 -SO ₂ —, —O ₂ S— (CR42 ₂ ) _d4 —SO ₂ — or —OC— (CR42 ₂ ) _d4 —SO ₂ —, wherein R41 and R43 are hydrogen, alkyl, halogen or halogenated An alkyl group, at least one of which is a halogen group or a halogenated alkyl group, and R42 is a hydrogen group, an alkyl group, a halogen group, or a halogenated alkyl group. A4, e4 and n4 are integers of 1 or 2, b4 and d4 are integers of 1 to 4, c4 is an integer of 0 to 4, and f4 and m4 are integers of 1 to 3. )

(X51 is a group 1A element or a group 2A element in the short period type periodic table. M51 is a transition metal, or a group 3B element, a group 4B element or a group 5B element in the short period type periodic table. Rf is a fluorinated alkyl. Or a fluorinated aryl group, each having 1 to 10 carbon atoms Y51 is —OC— (CR51 ₂ ) _d5 —CO—, —R52 ₂ C— (CR51 ₂ ) _d5 —CO—, —R52 _{2 C- (CR51 2) d5 -CR52} 2 -, - R52 2 C- (CR51 2) d5 -SO 2 -, - O 2 S- (CR51 2) e5 -SO 2 - or -OC- (CR51 _{2) e5} -SO ₂ -. is, however, R51 is a hydrogen group, an alkyl group, is .R52 is the halogen group or the halogenated alkyl group be a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group At least one of them is a halogen group or a halogenated alkyl group, wherein a5, f5 and n5 are integers of 1 or 2, b5, c5 and e5 are integers of 1 to 4, and d5 is 0 to 0. 4 is an integer, and g5 and m5 are integers of 1 to 3.) Compound shown in the Formula 5 is at least one of the compounds represented by formula 8, the compound shown in the formula 6 is at least one of the compounds represented by the formula 9 with There, the compound shown in the formula 7 is a compound represented by formula 10, claim 11 lithium ion secondary battery according.

Including at least one electrolyte salt containing lithium ion secondary battery according to claim 1, wherein one of the formula 11, Formula 12 and Formula 13 compounds represented by.

(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 negative electrode carbon material, Or, containing a negative electrode active material containing materials, comprising at least one of metal elements and semi-metal elements together can be inserting and extracting lithium ions, The lithium ion secondary battery according to claim 1. The negative electrode, elemental silicon (Si), alloys and compounds, as well as simple substance of tin (Sn), including a negative electrode active material containing at least one of alloys and compounds, according to claim 1 Lithium ion secondary according Next battery. The negative electrode includes a negative electrode active material layer on an anode current collector, the negative active material layer, a gas phase method are formed by at least one method of liquid-phase method and firing method, according to claim The lithium ion secondary battery according to 1. Of look-containing solvent containing a sulfone compound represented by 14, the content of the sulfone compound represented by the formula 14 in the solvent is 10 wt% or less than 0.01 wt%, a lithium ion secondary battery use electrolyte.

Images