JP2010165667A - Additive for electrolyte - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an additive for electrolyte forming a negative electrode protection film hardly decomposed even under high-temperature and overcharge conditions to improve the charge and discharge cycle characteristic. <P>SOLUTION: The additive for electrolyte contains a modified polysiloxane containing nitrogen atoms constituting onium salt and the modified polysiloxane (A) prepared by bonding the nitrogen atom with an organic group (a) having a polymerizable unsaturated bond, and preferably, further contains an electrolyte dissociation accelerator (B), a polycarbonate compound (C) having a polymerizable unsaturated bond and a compound (D) having a vinyl ether group or propenyl ether group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an additive for electrolytic solutions. More specifically, the present invention relates to an electrolytic solution additive for forming a negative electrode protective film and an electrolytic solution containing the same.

  In recent years, there is an increasing demand for secondary batteries that can be repeatedly charged and discharged as power supply devices for electronic products such as mobile phones and personal computers. Among them, lithium secondary batteries are actively developed because they can be increased in voltage, reduced in size, and reduced in weight. Conventionally, for the purpose of improving the battery characteristics of a lithium secondary battery, attempts have been made to mix various additives into the electrolytic solution. For example, in Patent Documents 1 and 2, vinylene carbonate (hereinafter abbreviated as VC) is used in order to prevent the carbonic acid ester used as the electrolyte from being decomposed at the negative electrode and deteriorating the charge / discharge cycle characteristics. ) And vinyl ethylene carbonate (hereinafter abbreviated as VEC) are added to the electrolytic solution, and VC, VEC, etc. are electropolymerized on the negative electrode to form a negative electrode protective film. ing.

  However, the negative electrode protective film produced from carbonates having double bonds is not sufficient in heat resistance and voltage resistance, and is thermally or electrically decomposed under high temperature conditions or overcharge conditions. Caused fire. In Patent Document 3, it is proposed to use a phosphite as a nonaqueous solvent for the purpose of enhancing the voltage resistance of the lithium secondary battery. However, even if phosphite is used as a non-aqueous solvent, there is a problem that the voltage resistance is not sufficient.

JP 2003-151621 A JP 2003-031259 A JP 9-167635 A

  An object of the present invention is to provide an additive for an electrolytic solution that forms a negative electrode protective film that is not easily decomposed even under high temperature and overcharge conditions, and improves charge / discharge cycle characteristics.

  The inventors of the present invention have reached the present invention as a result of studies to achieve the above object. That is, the present invention provides a modified polysiloxane having a nitrogen atom constituting an onium salt, wherein the nitrogen atom is bonded to an organic group (a) having a polymerizable unsaturated bond. And an electrolyte solution containing the electrolyte solution additive and the electrolyte solution additive.

  When the additive for electrolyte solution of the present invention is added to the electrolyte solution, it has an effect of suppressing deterioration of charge / discharge cycle characteristics under high temperature and overcharge conditions.

  Hereinafter, the present invention will be described in more detail. The onium salt in the present invention is an onium salt having one or more (preferably one or two) nitrogen atoms in the cation portion of the onium salt. In the onium salt, at least one nitrogen atom is bonded to an organic group (a) having a polymerizable unsaturated bond. Since the onium salt has the polymerizable unsaturated bond, it becomes easy to form a polymer as a protective film on the negative electrode surface of the secondary battery, and a protective film with good adhesion is formed. This has the effect of suppressing the deterioration of the characteristics. In the present invention, the polymerizable unsaturated bond means a polymerizable ethylenically unsaturated bond.

Examples of onium salts include amine salts, amidinium salts, and ammonium salts. Examples of the amine salt include salts obtained by adding protons to primary to tertiary amines. Examples of amidinium salts include imidazolinium salts, imidazolium salts, pyrimidinium salts, and tetrahydropyrimidinium salts. As the ammonium salt, salts and quaternary ammonium salts such as ammonium ion (NH4 ⁺⁾ and the like. Of the onium salts, amidinium salts and ammonium salts are preferable from the viewpoint of charge / discharge cycle characteristics, imidazolium salts and quaternary ammonium salts are more preferable, and imidazolium salts are particularly preferable.

  As modified polysiloxane (A) in this invention, the compound represented by General formula (1) or General formula (2) is mentioned. Among these, the modified polysiloxane represented by the general formula (2) is preferable from the viewpoint of battery output.

式中、Ｒ１、Ｒ２、Ｒ３、Ｒ４及びＲ５は、それぞれ独立して、アルキル基、ハロゲン化アルキル基、アリール基、アラルキル基、アルコキシ基及びアリールオキシ基からなる群から選ばれる少なくとも一種であり、Ｑ１はオニウム塩を構成する窒素原子及び重合性不飽和結合を有する基、ａは０〜２００の数、ｂは４〜２００の数であり、ｃ及びｄはそれぞれ独立して０又は１である。また、一般式（１）における［Ｓｉ（Ｒ²）（Ｒ³）Ｏ］_a、［Ｓｉ（Ｑ¹）（Ｒ⁴）Ｏ］_bの付加形式は、ブロック状でもランダム状でもよい。

In the formula, R1, R2, R3, R4 and R5 are each independently at least one selected from the group consisting of an alkyl group, a halogenated alkyl group, an aryl group, an aralkyl group, an alkoxy group and an aryloxy group, Q1 is a group having a nitrogen atom constituting a onium salt and a polymerizable unsaturated bond, a is a number from 0 to 200, b is a number from 4 to 200, and c and d are each independently 0 or 1 . The addition form of [Si (R ² ) (R ³ ) O] _a and [Si (Q ¹ ) (R ⁴ ) O] _{b in} the general formula (1) may be block or random.

  R1, R2, R3, R4 and R5 in the general formula (1) are preferably alkyl groups from the viewpoint of battery output. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. A methyl group is preferable from the viewpoint of battery output. a is preferably 0 to 20 from the viewpoint of battery output. b is preferably from 4 to 80 from the viewpoint of charge / discharge cycle characteristics. c and d are preferably 1 from the viewpoint of charge / discharge cycle characteristics.

式中、Ｒ６、Ｒ７及びＲ８は、それぞれ独立して、アルキル基、ハロゲン化アルキル基、アリール基、アラルキル基、アルコキシ基及びアリールオキシ基からなる群より選ばれる少なくとも一種であり、Ｑ２はオニウム塩を構成する窒素原子及び重合性不飽和結合を有する基、ｅは０〜１００の数、ｆは１〜１００の数であって、かつｅ＋ｆは７〜２００である。
また、一般式（２）における［Ｓｉ（Ｒ⁶）（Ｒ⁷）Ｏ］_e、［Ｓｉ（Ｑ²）（Ｒ⁸）Ｏ］_fの付加形式は、ブロック状でもランダム状でもよい。

In the formula, R6, R7 and R8 are each independently at least one selected from the group consisting of an alkyl group, a halogenated alkyl group, an aryl group, an aralkyl group, an alkoxy group and an aryloxy group, and Q2 is an onium salt. And a group having a polymerizable unsaturated bond, e is a number from 0 to 100, f is a number from 1 to 100, and e + f is 7 to 200.
In addition, the addition form of [Si (R ⁶ ) (R ⁷ ) O] _e and [Si (Q ² ) (R ⁸ ) O] _{f in} the general formula (2) may be block or random.

  R6, R7 and R8 in the general formula (2) are preferably alkyl groups from the viewpoint of battery output. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. A methyl group is preferable from the viewpoint of battery output. From the viewpoint of lithium ion stability and solubility in the electrolytic solution, e and f are preferably 5 to 20 for e and f, and 7 to 40 for e + f, more preferably 5 for each of e and f. -10 and e + f is 7-20.

  Examples of Q1 in the general formula (1) and Q2 in the general formula (2) include a group represented by the general formula (3).

式中、Ｒ９は水素原子、メチル基又はエチル基、Ａ１は重合性不飽和結合を有する有機基（ａ）、Ｘ−はアニオンを表す。

In the formula, R9 represents a hydrogen atom, a methyl group or an ethyl group, A1 represents an organic group (a) having a polymerizable unsaturated bond, and X- represents an anion.

  Examples of R9 in the general formula (3) include a hydrogen atom, a methyl group, and an ethyl group. From the viewpoint of heat resistance and alkali resistance, a methyl group and an ethyl group are preferable, and a methyl group is more preferable.

  A1 in the general formula (3) is an organic group (a) having a polymerizable unsaturated bond, and the organic group (a) is an organic group having a polymerizable ethylenically unsaturated bond. Examples of the organic group (a) include a group represented by the general formula (5), a group represented by the general formula (6), a (meth) acryloyloxyalkyl group, and a (meth) acryloylalkyl group. Among these, the group represented by the general formula (5), the group represented by the general formula (6), and the (meth) acryloyloxyalkyl group are preferable from the viewpoint of charge / discharge cycle characteristics.

式中、Ｒ１２は炭素数１〜３のアルキレン基、Ｑ３、Ｑ４及びＱ５は、それぞれ独立して水素原子、炭素数が１〜４のアルキル基、フェニル基、ハロゲン原子、フルオロアルキル基、シアノ基、カルボキシル基、アルコキシ基又はアルコキシカルボニル基である。

In the formula, R12 is an alkylene group having 1 to 3 carbon atoms, Q3, Q4 and Q5 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a halogen atom, a fluoroalkyl group, a cyano group. A carboxyl group, an alkoxy group or an alkoxycarbonyl group.

Examples of the alkylene group having 1 to 3 carbon atoms include a methylene group, an ethylene group, a 1,2-propylene group, and a 1,3-propylene group. Among these, a methylene group and an ethylene group are preferable from the viewpoint of compatibility with the electrolytic solution.
Examples of the alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, and t-butyl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the fluoroalkyl group include those in which 1 to 5 hydrogen atoms on a methyl group or an ethyl group are substituted with fluorine atoms. For example, a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a fluoroethyl group, Examples thereof include a difluoroethyl group, a trifluoroethyl group, a tetrafluoroethyl group, and a pentafluoroethyl group.
As an alkoxy group, a C1-C3 alkoxy group is mentioned, For example, a methoxy group, an ethoxy group, n-propoxy group, and an isopropoxy group are mentioned.
Examples of the alkoxycarbonyl group include those having 1 to 3 carbon atoms in the alkoxy group, such as a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, and an isopropoxycarbonyl group.

Preferred combinations of Q3, Q4 and Q5 include the following (1) to (6).
(1) Q3 = hydrogen atom, Q4 = hydrogen atom, Q5 = phenyl group (2) Q3 = hydrogen atom, Q4 = hydrogen atom, Q5 = alkoxycarbonyl group (3) Q3 = phenyl group, Q4 = hydrogen atom, Q5 = Phenyl group (4) Q3 = phenyl group, Q4 = hydrogen atom, Q5 = alkoxycarbonyl group (5) Q3 = alkoxycarbonyl group, Q4 = hydrogen atom, Q5 = phenyl group (6) Q3 = alkoxycarbonyl group, Q4 = hydrogen Atom, Q5 = alkoxycarbonyl group Among these combinations, the combination of (2) is more preferable.

式中、Ｒ１３は炭素数１〜３のアルキレン基であり、Ｑ６は水素原子又はハロゲン原子であり、Ｑ７、Ｑ８及びＱ９は、それぞれ独立して水素原子、炭素数が１〜４のアルキル基、フェニル基、ハロゲン原子、フルオロアルキル基、シアノ基、カルボキシル基、アルコキシ基又はアルコキシカルボニル基である。これらの基の具体例としては、前記Ｒ１３、Ｑ３、Ｑ４及びＱ５で例示した基と同じ基が挙げられる。Ｑ６のうち、充放電サイクル特性及び重合性不飽和結合を有する有機基（ａ）の安定性の観点から好ましいのは、水素原子、フッ素原子及び塩素原子であり、更に好ましいのは水素原子である。
Ｑ７のうち、充放電サイクル特性の観点から好ましいのは水素原子である。Ｑ８及びＱ９のうち、充放電サイクル特性の観点から好ましいのは水素原子及びメチル基であり、更に好ましいのは水素原子である。

In the formula, R13 is an alkylene group having 1 to 3 carbon atoms, Q6 is a hydrogen atom or a halogen atom, Q7, Q8 and Q9 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, A phenyl group, a halogen atom, a fluoroalkyl group, a cyano group, a carboxyl group, an alkoxy group or an alkoxycarbonyl group. Specific examples of these groups include the same groups as those exemplified for R13, Q3, Q4 and Q5. Of Q6, a hydrogen atom, a fluorine atom and a chlorine atom are preferred from the viewpoint of charge / discharge cycle characteristics and the stability of the organic group (a) having a polymerizable unsaturated bond, and a hydrogen atom is more preferred. .
Of Q7, a hydrogen atom is preferable from the viewpoint of charge / discharge cycle characteristics. Of Q8 and Q9, a hydrogen atom and a methyl group are preferable from the viewpoint of charge / discharge cycle characteristics, and a hydrogen atom is more preferable.

Preferred combinations of Q6, Q7, Q8 and Q9 include the following (1) to (12).
(1) Q6 = hydrogen atom, Q7 = hydrogen atom, Q8 = hydrogen atom, Q9 = hydrogen atom (2) Q6 = fluorine atom, Q7 = hydrogen atom, Q8 = hydrogen atom, Q9 = hydrogen atom (3) Q6 = chlorine Atom, Q7 = hydrogen atom, Q8 = hydrogen atom, Q9 = hydrogen atom (4) Q6 = hydrogen atom, Q7 = hydrogen atom, Q8 = methyl group, Q9 = hydrogen atom (5) Q6 = fluorine atom, Q7 = hydrogen atom Q8 = methyl group, Q9 = hydrogen atom (6) Q6 = chlorine atom, Q7 = hydrogen atom, Q8 = methyl group, Q9 = hydrogen atom (7) Q6 = hydrogen atom, Q7 = hydrogen atom, Q8 = hydrogen atom, Q9 = methyl group (8) Q6 = fluorine atom, Q7 = hydrogen atom, Q8 = hydrogen atom, Q9 = methyl group (9) Q6 = chlorine atom, Q7 = hydrogen atom, Q8 = hydrogen atom, Q9 = methyl group (10 Q6 = Hydrogen atom, Q7 = Hydrogen atom, Q8 = Me Q9 = methyl group (11) Q6 = fluorine atom, Q7 = hydrogen atom, Q8 = methyl group, Q9 = methyl group (12) Q6 = chlorine atom, Q7 = hydrogen atom, Q8 = methyl group, Q9 = methyl Group Among these combinations, the combination of (1) is more preferable.

  Examples of the (meth) acryloyloxyalkyl group in the organic group (a) having a polymerizable unsaturated bond in the present invention include an acryloyloxyethyl group, an acryloyloxypropyl group, and a methacryloyloxymethyl group.

  Examples of the (meth) acryloylalkyl group in the organic group (a) having a polymerizable unsaturated bond in the present invention include an acryloylethyl group and a methacryloylethyl group.

  X- in the general formula (3) includes Cl-, Br-, I-, PF6-, BF4-, SbF6-, AsF6-, ClO4-, N (CF3SO2) 2-, N (C2F5SO2) 2- and C. (CF3SO2) 3- and the like. Of these, PF6-, BF4-, SbF6-, AsF6- and ClO4- are preferable from the viewpoint of battery output, and PF6- is more preferable.

式中、Ｒ１０は炭素数２〜４のアルキレン基、Ｒ１１は炭素数１〜３のアルキル基、Ａ２は重合性不飽和結合を有する有機基（ａ）、ｍは１〜５の数、ｇは１〜３の整数、Ｙ−はアニオンを表す。 Examples of Q1 in the general formula (1) and Q2 in the general formula (2) include a group represented by the general formula (4).

In the formula, R10 is an alkylene group having 2 to 4 carbon atoms, R11 is an alkyl group having 1 to 3 carbon atoms, A2 is an organic group (a) having a polymerizable unsaturated bond, m is a number of 1 to 5, and g is An integer of 1 to 3, Y- represents an anion.

  R10 in the general formula (4) is preferably an ethylene group from the viewpoint of battery output. R11 is preferably a methyl group from the viewpoint of battery output and charge / discharge cycle characteristics. From the viewpoint of charge / discharge cycle characteristics, m is preferably 1 to 3, and more preferably 1 to 2. g is preferably 1 or 2 from the viewpoint of battery output and charge / discharge cycle characteristics.

  As A2 in General formula (4), the thing similar to A1 in the said General formula (3) is mentioned. Examples of Y- include the same as X- in the general formula (3).

  Specific examples of the modified polysiloxane represented by the general formula (1) include [N- (2-butenoic acid methyl) imidazolium hexafluorophosphate] modified polysiloxane [in the general formula (1), R1, R2, R3, R4 and R5 = methyl group, a and b = 5, c and d = 0, Q1 is a group represented by the general formula (3), R9 = hydrogen atom, X- is PF6-, and A1 is A compound represented by the general formula (5), wherein R12 is a methylene group, Q3 and Q4 are hydrogen atoms, and Q5 is a methoxycarbonyl group], [N- (3-acryloyloxypropyl) imidazolium hexafluoro Phosphate] modified polysiloxane [in general formula (1), R1, R2, R3, R4 and R5 = methyl group, a and b = 5, c and d = 0, Q1 is represented by general formula (3) Group R9 = a hydrogen atom, a compound in which X- is PF6- and A1 is an acryloyloxypropyl group], [N- (4-vinylbenzyl) imidazolium hexafluorophosphate] -modified polysiloxane [in the general formula (1) , R1, R2, R3, R4 and R5 = methyl group, a and b = 5, c and d = 0, Q1 is a group represented by the general formula (3), R9 = hydrogen atom, X— PF6-, A1 is a group represented by the general formula (6), and R18 = methylene group, Q6, Q7, Q8 and Q9 = a hydrogen atom], [N- (3-acryloyloxypropyl) imidazo [Rium tetrafluoroborate] modified polysiloxane [in the general formula (1), R1, R2 = methyl group, R3, R4 and R5 = ethyl group, a and b = 5, c and d = 0, Q1 is a general formula 3), wherein R9 = methyl group, X- is BF4-, and A1 is acryloyloxypropyl group] and (4-vinylbenzyl) imidazolium tetrafluoroborate-modified polysiloxane [general In the formula (1), R1, R2, R3, R4 and R5 = methyl group, a and b = 5, c and d = 0, Q1 is a group represented by the general formula (3), and R9 = methyl A group represented by formula (6), wherein R18 = methylene group, Q6, Q7, Q8 and Q9 = hydrogen atom], [N- (2- Methyl butenoate) imidazolium hexafluorophosphate] modified polysiloxane [in general formula (1), R1, R2, R3, R4 and R5 = methyl group, a and b = 5, c and d = 0, Q1 is general Expressed by equation (4) R10 = ethylene group, R11 = methyl group, g = 1, m = 2, Y- is PF6-, A2 is a group represented by the general formula (5), and R12 is methylene. Group, Q3 and Q4 are hydrogen atoms, Q5 is a methoxycarbonyl group], [N, N, N-di (3,6-dioxaheptyl) (3-acryloyloxypropyl) ammonium hexafluorophosphate] modification Polysiloxane [In the general formula (1), R1, R2, R3, R4 and R5 = methyl group, a and b = 5, c and d = 0, Q1 is a group represented by the general formula (4) , R10 = ethylene group, R11 = methyl group, g = 1, m = 2, Y- is PF6-, and A2 is an acryloyloxypropyl group], [N, N, N-di (3,6-di) Oxaheptyl) (4-vinylbenze) ) Ammonium hexafluorophosphate] modified polysiloxane [in the general formula (1), R1, R2, R3, R4 and R5 = methyl group, a and b = 5, c and d = 0, Q1 is the general formula (4) R10 = ethylene group, R11 = methyl group, g = 1, m = 2, Y- is PF6-, A2 is a group represented by the general formula (6), and R18 = Methylene group, Q6, Q7, Q8 and Q9 = compound in which hydrogen atom], N ′-[N, N, N-di (3,6-dioxaheptyl) (3-acryloyloxypropyl) ammonium tetrafluorobo Lat] modified polysiloxane [in general formula (1), R1, R2 = methyl group, R3, R4 and R5 = ethyl group, a and b = 5, c and d = 0, Q1 is represented by general formula (4) Wherein R9 = Compound wherein til group, Y- is BF4-, and A1 is acryloyloxypropyl group] and [N, N, N-di (3,6-dioxaheptyl) (4-vinylbenzyl) ammonium tetrafluoroborate] modified Polysiloxane [In the general formula (1), R1, R2, R3, R4 and R5 = methyl group, a and b = 5, c and d = 0, Q1 is a group represented by the general formula (4) R10 = ethylene group, R11 = methyl group, g = 1, m = 2, Y- is BF4-, A2 is a group represented by the general formula (6), and R13 = methylene group, Q6, Q7, Q8 and Q9 = compounds having a hydrogen atom] and the like.

  Specific examples of the modified polysiloxane represented by the general formula (2) include [N- (methyl 2-butenoate) imidazolium hexafluorophosphate] modified polysiloxane [in the general formula (2), R6, R7 and R8 = methyl group, e = 5, f = 5, Q2 is a group represented by the general formula (3), R9 = hydrogen atom, X- is PF6-, and A1 is represented by the general formula (5). A compound in which R12 is a methylene group, Q3 and Q4 are hydrogen atoms, and Q5 is a methoxycarbonyl group], [N- (3-acryloyloxypropyl) imidazolium hexafluorophosphate] -modified polysiloxane [general In the formula (2), R6, R7 and R8 = methyl group, e = 5, f = 5, Q2 is a group represented by the general formula (3), R9 = hydrogen atom, X- is PF6-, A1 is Compound that is a loyloxypropyl group], [N- (4-vinylbenzyl) imidazolium hexafluorophosphate] modified polysiloxane [in the general formula (2), R6, R7 and R8 = methyl group, e = 5, f = 5, Q2 is a group represented by the general formula (3), R9 = hydrogen atom, X- is PF6-, A1 is a group represented by the general formula (6), and R13 = methylene group , Q6, Q7, Q8 and Q9 = compounds wherein hydrogen atom], [N, N, N-di (3,6-dioxaheptyl) (methyl 2-butenoate) ammonium hexafluorophosphate] modified polysiloxane [ In general formula (2), R6, R7 and R8 = methyl group, e = 5, f = 5, Q2 is a group represented by general formula (4), R10 = ethylene group, R11 = methyl group, g = 1, m = , Y- is a group represented by PF6-, A2 is a group represented by the general formula (5), R12 is a methylene group, Q3 and Q4 are hydrogen atoms, and Q5 is a methoxycarbonyl group], [N, N, N-di (3,6-dioxaheptyl) (3-acryloyloxypropyl) ammonium hexafluorophosphate] modified polysiloxane [in general formula (2), R6, R7 and R8 = methyl group, e = 5, f = 5, Q2 is a group represented by the general formula (4), R10 = ethylene group, R11 = methyl group, g = 1, m = 2, Y- is PF6-, and A2 is acryloyloxypropyl group. A certain compound], [N, N, N-di (3,6-dioxaheptyl) (4-vinylbenzyl) ammonium hexafluoroborate] modified polysiloxane [in the general formula (2), R6, R7 and R8 = methyl group, e = 2, f = 4, Q2 is a group represented by the general formula (4), and R10 = ethylene group, R11 = methyl group, g = 1, m = 2, Y— Is a group represented by formula (6), wherein R13 = methylene group, Q6, Q7, Q8 and Q9 = hydrogen atoms], [N, N, N- (3, 6-dioxaheptyl) di (3-acryloyloxypropyl) ammonium hexafluoroborate] modified polysiloxane [in general formula (2), R6, R7 = methyl group, R8 = ethyl group, e = 5, f = 5 , Q2 is a group represented by the general formula (4), R10 = ethylene group, R11 = methyl group, g = 2, n = 2, Y- is BF4-, and A2 is an acryloyloxypropyl group ], [N, N, N-di (3,6-dioxaheptyl (4-Vinylbenzyl) ammonium hexafluorophosphate] modified polysiloxane [in general formula (2), R6, R7 and R8 = methyl group, e = 5, f = 5, Q2 is represented by general formula (4) R10 = ethylene group, R11 = methyl group, g = 2, n = 2, Y— is PF6-, A2 is a group represented by the general formula (6), and R13 = methylene group , Q6, Q7, Q8 and Q9 = compounds in which a hydrogen atom is present] and the like.

  There is no restriction | limiting in particular about the manufacturing method of the modified polysiloxane in this invention, It can manufacture by a normal method. For example, an alkyl halide-modified polysiloxane is synthesized by hydrolytic polycondensation of a mixture of an alkyl halide-modified silane and a hydrolyzable silane, and further reacted with an imidazole derivative or an amine derivative having a polymerizable unsaturated bond to produce an onium salt. In addition, after synthesizing a modified polysiloxane having a polymerizable unsaturated bond, an anion exchange reaction may be performed with a halogen ion which is a counter ion of an onium salt, if necessary.

  Examples of the alkyl halide-modified silane include chloromethyldimethoxymethylsilane, (2-bromoethyl) dimethoxymethylsilane, (3-bromopropyl) dimethoxymethylsilane, (4-bromobutyl) dimethoxymethylsilane, di (chloromethyl) dimethoxysilane, Di (2-bromoethyl) dimethoxysilane, di (3-bromopropyl) dimethoxysilane, di (4-bromobutyl) dimethoxysilane, chloromethyldimethylmethoxysilane, (2-bromoethyl) dimethylmethoxysilane, (3-bromopropyl) dimethyl Examples include methoxysilane and (4-bromobutyl) dimethylmethoxysilane.

  Examples of the hydrolyzable silane include dimethoxydimethylsilane, dimethoxyethylmethylsilane, dimethoxydiethylsilane, methoxyethyldimethylsilane, methoxydiethylmethylsilane, methoxytrimethylsilane, and methoxytriethylsilane.

  Hydrolysis polycondensation can be carried out by a known hydrolysis method, but the amount of water used is usually hydrolyzable per molecule of the modified silane with respect to 1 mol of the modified silane having the hydrolyzable group. Depending on the number of moles of the group, it is 0.3 to 3 moles, preferably 0.4 to 2.4 moles. Moreover, you may use organic solvents, such as alcohol, as a compatibilizing agent of modified silane and water, and the usage-amount of an organic solvent can use 0.2-100 mol with respect to 1 mol of said modified silane. . Examples of the hydrolysis catalyst include acidic catalysts such as sulfuric acid, methanesulfonic acid, hydrochloric acid, phosphoric acid, formic acid, acetic acid and trifluoroacetic acid, and alkaline catalysts such as sodium hydroxide, potassium hydroxide and magnesium hydroxide. The amount of the catalyst used is usually 0.1 to 10% by weight based on the total weight of the reaction solution. The reaction temperature is −50 to 40 ° C., preferably −20 to 20 ° C. The reaction time is usually 1 to 10 hours.

  There is no restriction | limiting in particular about the manufacturing method of the imidazole derivative or amine derivative which has the said polymerizable unsaturated bond, It can manufacture by a normal method. Examples thereof include a method of reacting an imidazole derivative or amine with an alkyl halide having an organic group (a) having a polymerizable unsaturated bond in an organic solvent in the absence of a catalyst or in the presence of a catalyst. Examples of organic solvents include nitrile organic solvents (acetonitrile, propiononitrile, benzonitrile, etc.), ketone organic solvents (acetone, methyl ethyl ketone, etc.), amide organic solvents (formamide, acetamide, dimethylformamide, dimethylacetamide, etc.) , Ether organic solvents (such as dimethyl ether, tetrahydrofuran and dioxane), ester organic solvents (such as ethyl acetate and diethyl maleate), sulfur-containing organic solvents (such as dimethyl sulfoxide and sulfolane), halogenated hydrocarbons (such as chloroform and dichloromethane) , Hydrocarbons (hexane, heptane, toluene, xylene, etc.) and mixtures of two or more of these solvents. Catalysts include alkali metal hydroxides (for example, lithium hydroxide, sodium hydroxide and potassium hydroxide), alkali metal carbonates (such as sodium bicarbonate, potassium bicarbonate, sodium carbonate and potassium carbonate) and alkali metal hydrides. (Such as sodium hydride and potassium hydride). The reaction temperature is usually 10 to 150 ° C., and the reaction time is usually 0.5 to 24 hours. After completion of the reaction, if necessary, the catalyst can be neutralized and treated with an adsorbent to remove and purify the catalyst.

  Examples of the halogenated alkyl having an organic group (a) having a polymerizable unsaturated bond include 4-bromo-2-butenoic acid methyl ester, 4-chloro-2-butenoic acid methyl ester, and 1-bromo-4. -Cyano-2-butene, 1-chloro-4-cyano-2-butene, acrylic acid chloromethyl ester, acrylic acid bromomethyl ester, acrylic acid-2-chloroethyl ester, acrylic acid-2-bromoethyl ester, methacrylic acid Acid chloromethyl ester, methacrylic acid bromomethyl ester, methacrylic acid-2-chloroethyl ester, methacrylic acid-2-bromoethyl ester, 4-chloromethylstyrene, 4- (2-chloroethyl) styrene and 1- (3-chloro Propyl) styrene and the like.

  The electrolyte salt dissociation accelerator (B) in the present invention comprises a sulfoxide compound and / or an ether compound, and examples of the sulfoxide compound include compounds represented by the general formula (7).

式中、Ｒ１４及びＲ１５はそれぞれ独立して炭素数１〜５のアルキル基である。炭素数が１〜５のアルキル基としては、メチル基、エチル基、ｎ−プロピル基、イソプロピル基、ｎ−ブチル基、イソブチル基及びｔ−ブチル基、ｎ−ペンチル基、イソペンチル基及び２，２−ジメチルプロピル基等が挙げられる。これらのうち、電池出力の観点から好ましいのはメチル基である。

In the formula, R14 and R15 are each independently an alkyl group having 1 to 5 carbon atoms. Examples of the alkyl group having 1 to 5 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group and t-butyl group, n-pentyl group, isopentyl group, and 2,2. -A dimethylpropyl group etc. are mentioned. Among these, a methyl group is preferable from the viewpoint of battery output.

  Specific examples of the sulfoxide compound include dimethyl sulfoxide, ethyl methyl sulfoxide, methyl n-propyl sulfoxide, butyl methyl sulfoxide, methyl pentyl sulfoxide, diethyl sulfoxide, ethyl isopropyl sulfoxide, n-butyl ethyl sulfoxide, ethyl n-pentyl sulfoxide, diisopropyl sulfoxide. N-butyl n-propyl sulfoxide, isopentyl n-propyl sulfoxide, di-n-butyl sulfoxide, butyl 2,2-dimethylpropyl sulfoxide, diisopentyl sulfoxide and the like.

  As a manufacturing method of a sulfoxide compound, the method of oxidizing and manufacturing the alkyl sulfide which has a C1-C5 alkyl with an oxidizing agent is mentioned. Examples of the oxidizing agent include hydrogen peroxide and perhalogenates (such as sodium perchlorate, sodium perbromate, and sodium periodate). The reaction temperature is usually 0 to 100 ° C., and the reaction time is usually 1 to 10 hours. After completion of the reaction, the oxidizing agent can be decomposed with a reducing agent (sodium thiosulfate, sodium hydrogensulfite, etc.) and then treated with an adsorbent for removal and purification.

As an ether compound in this invention, the compound shown by General formula (8) is mentioned.
R16-O- (CH2CH2O) n-R17 (8)
In the formula, R16 and R17 are each independently an alkyl group having 1 to 5 carbon atoms, and n is a number of 1 to 10. Examples of the alkyl group having 1 to 5 carbon atoms include the same groups as R14 and R15 in the general formula (7). Of R16 and R17, a methyl group is preferable from the viewpoint of battery output. n is preferably 1 or 2 from the viewpoint of the electrolyte solution viscosity.

  Specific examples of the ether compound include dimethoxyethane, diethoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, pentaethylene glycol dimethyl ether, penta Ethylene glycol diethyl ether, hexaethylene glycol ethyl methyl ether, hexaethylene glycol n-butylisopentyl ether, heptaethylene glycol isobutyl n-propyl ether, heptaethylene glycol ethyl 2,2-dimethylpropyl ether, octaethylene glycol ethyl n-propyl ether, Kuta ethylene glycol diisobutyl ether, nonaethylene glycol dimethyl ether, nonaethylene glycol t- butyl isopropyl ether, decaethylene glycol diisopropyl ether and decamethylene glycol 2,2-dimethylpropyl isopentyl ether, and the like.

As a manufacturing method of an ether compound, the method of manufacturing through the following processes is mentioned.
(1): A monohydric alcohol having 1 to 5 carbon atoms is charged into a pressurized reaction vessel, ethylene oxide is blown in the presence of no catalyst or a catalyst, and ethylene oxide is added in one step or multiple steps under normal pressure or pressure. Perform the reaction.
(2): The hydroxyl group of the ethylene oxide adduct of a monohydric alcohol having 1 to 5 carbon atoms obtained in (1) is etherified with an etherifying agent.
As a catalyst for the addition reaction of a monohydric alcohol having 1 to 5 carbon atoms and ethylene oxide, an alkali catalyst [for example, alkali metal (lithium, sodium, potassium, cesium, etc.)] hydroxide, acid [perhalogen acid (perchlorine Acid, perbromic acid and periodic acid), sulfuric acid, phosphoric acid and nitric acid (preferably perchloric acid)] and salts thereof [preferably divalent or trivalent metals (Mg, Ca, Sr, Ba) , Zn, Co, Ni, Cu and Al). The reaction temperature is usually 50 to 150 ° C., and the reaction time is usually 2 to 20 hours. After completion of the addition reaction of ethylene oxide, the catalyst can be neutralized if necessary and treated with an adsorbent to remove and purify the catalyst.
Examples of the catalyst for the etherification reaction of an ethylene oxide adduct of a monohydric alcohol having 1 to 5 carbon atoms include hydroxides of alkali catalysts [eg, alkali metals (lithium, sodium, potassium, cesium, etc.)]. Examples of the etherifying agent include alkyl chloride or alkyl bromide having 1 to 5 carbon atoms, such as methyl chloride, methyl bromide, ethyl chloride, ethyl bromide, n-propyl chloride, n-propyl bromide, and chloride. Isopropyl, isopropyl bromide, n-butyl chloride, n-butyl bromide, isobutyl chloride, isobutyl bromide, t-butyl chloride, t-butyl bromide, n-pentyl chloride, n-pentyl bromide, isopentyl chloride, odor Isopentyl chloride, 2,2-dimethylpropyl chloride, 2,2-dimethylpropyl bromide and the like. The reaction temperature is usually 50 to 100 ° C., and the reaction time is usually 6 to 24 hours. The equivalent ratio of the etherifying agent to the ethylene oxide adduct of a monohydric alcohol having 1 to 5 carbon atoms is preferably 1-2. In the etherification reaction, a solvent such as toluene or benzene can be used as necessary. After completion of the reaction, the unreacted etherifying agent and solvent can be distilled off under reduced pressure, the catalyst can be neutralized, and the catalyst can be removed and purified by treating with an adsorbent.

  Of the sulfoxide compounds and ether compounds, ether compounds are preferable from the viewpoint of battery capacity, and dimethoxyethane, diethoxyethane, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether are more preferable from the viewpoints of volatility and electrolyte viscosity.

  The number of donors of the sulfoxide compound and the polyether compound in the present invention represents the affinity between the sulfoxide compound or the polyether compound and the electrolyte, and the coordination stabilization enthalpy for SbCl5 in 1,2-dichloroethane. It is a number obtained by measuring (kcal / mol). As the number of donors of typical compounds, for example, those described in “V. Gutmann, Hitoshi Ohtsuki, Isao Okada,“ Donor and Acceptor ”Society Publishing Center, published in 1983” can be used. The larger the number of donors, the higher the dissociation ability of the electrolyte. From the viewpoint of battery output, the number of donors of the sulfoxide compound and the polyether compound is preferably 16 to 40 and more preferably 20 to 30 for both the sulfoxide compound and the polyether compound. In order to increase the donor number of the sulfoxide compound in the present invention, the carbon number of the alkyl group having 1 to 5 carbon atoms of R14 and R15 in the general formula (7) may be decreased. In order to increase the number of donors of the ether compound in the present invention, the number of carbon atoms in the alkyl group having 1 to 5 carbon atoms of R16 and R17 in the general formula (8) may be decreased, and the number of n may be increased. . In order to reduce the number of donors of the ether compound, the number of carbon atoms in the alkyl group having 1 to 5 carbon atoms of R16 and R17 in the general formula (8) may be increased, and the number of n may be decreased. If the number of donors is 16 or more, the affinity with lithium ions is above a certain level, and the battery output does not decrease.

  Examples of the carbonate compound (C) having a polymerizable unsaturated bond include a chain carbonate compound (C1) having 4 to 7 carbon atoms and a cyclic carbonate compound (C2) having 3 to 9 carbon atoms. Among these, (C2) is preferable from the viewpoint of charge / discharge cycle characteristics. Examples of (C1) include methyl vinyl carbonate, ethyl vinyl carbonate, n-propyl vinyl carbonate, isopropyl vinyl carbonate, divinyl carbonate, allyl methyl carbonate, allyl ethyl carbonate, allyl n-propyl carbonate, allyl isopropyl carbonate, and diallyl carbonate. It is done. These can be obtained commercially.

  As a C3-C9 cyclic carbonate compound (C2), the compound shown by the compound shown by General formula (9), and General formula (10) is mentioned.

式中、Ｒ１８及びＲ１９は、それぞれ独立して水素原子又は炭素数１〜３のアルキル基である。炭素数が１〜３のアルキル基としては、メチル基、エチル基、ｎ−プロピル基及びイソプロピル基が挙げられる。これらのうち、充放電サイクル特性の観点から好ましいのは水素原子である。

In the formula, R18 and R19 are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. Among these, a hydrogen atom is preferable from the viewpoint of charge / discharge cycle characteristics.

  Specific examples of the compound represented by the general formula (9) include vinylene carbonate, methyl vinylene carbonate, ethyl vinylene carbonate, n-propyl vinylene carbonate, isopropyl vinylene carbonate, dimethyl vinylene carbonate, diethyl vinylene carbonate, and di-n-propyl vinylene carbonate. , Diisopropyl vinylene carbonate, ethyl methyl vinylene carbonate, ethyl n-propyl vinylene carbonate, and ethyl isopropyl vinylene carbonate. These can be obtained commercially.

式中、Ｒ２０及びＲ２１は、それぞれ独立して水素原子又は炭素数２〜３のアルケニル基であり、Ｒ２０及びＲ２１が共に水素原子となることはない。炭素数が２〜３のアルケニル基としては、ビニル基及びアリル基が挙げられる。これらのうち、充放電サイクル特性の観点から好ましいのは、水素原子及びビニル基である。

In the formula, R20 and R21 are each independently a hydrogen atom or an alkenyl group having 2 to 3 carbon atoms, and R20 and R21 are not both hydrogen atoms. Examples of the alkenyl group having 2 to 3 carbon atoms include a vinyl group and an allyl group. Among these, a hydrogen atom and a vinyl group are preferable from the viewpoint of charge / discharge cycle characteristics.

  Specific examples of the compound represented by the general formula (10) include vinyl ethylene carbonate, allyl ethylene carbonate, divinyl ethylene carbonate, and diallyl ethylene carbonate. These can be obtained commercially.

  As the compound (D) having a vinyl ether group or a propenyl ether group, a linear alkyl compound having 4 to 10 carbon atoms (D1) having a vinyl ether group or a propenyl ether group at both ends, and a vinyl ether group or a propenyl ether group at both ends. And an oligoether compound (D2) having two or more vinyl ether groups or propenyl ether groups (D3). Among these, (D3) is preferable from the viewpoint of charge / discharge cycle characteristics.

  As a C4-C10 linear alkyl compound (D1) which has a vinyl ether group or a propenyl ether group at both ends, the compound shown by General formula (11) is mentioned.

R22-CH = CH-O- (CH2) p-O-CH = CH-R23 (11)
In the formula, R22 and R23 are each independently a hydrogen atom or a methyl group, and p is a number of 4 to 10. Among these, from the viewpoint of charge / discharge cycle characteristics, preferred are compounds in which R22 and R23 are hydrogen atoms and p is 6-8.

  Specific examples of the compound represented by the general formula (11) include 1,4-butanediol divinyl ether, 1,5-pentanediol divinyl ether, 1,6-hexanediol divinyl ether, 1,7-heptanediol divinyl ether. 1,8-octanediol divinyl ether, 1,9-nonanediol divinyl ether, 1,10-decanediol divinyl ether, 1,4-butanediol propenyl vinyl ether, 1,5-pentanediol propenyl vinyl ether, 1,6- Hexanediol propenyl vinyl ether, 1,7-heptanediol propenyl vinyl ether, 1,8-octanediol propenyl vinyl ether, 1,9-nonanediol propenyl vinyl ether, 1,10-decanediol propenyl Vinyl ether, 1,4-butanediol dipropenyl ether, 1,5-pentadiol dipropenyl ether, 1,6-hexanediol dipropenyl ether, 1,7-heptanediol dipropenyl ether, 1,8-octanediol dipropenyl ether Examples include ether, 1,9-nonanediol dipropenyl ether and 1,10-decanediol dipropenyl ether. These can be obtained commercially.

  Examples of the oligoether compound (D2) having a vinyl ether group or a propenyl ether group at both ends include a compound represented by the general formula (12).

R24—CH═CH—O— (C2H4O) q—O—CH═CH—R25 (12)
In formula, R24 and R25 are respectively independently a hydrogen atom or a methyl group, and q is a number of 1-5. Among these, preferred is a compound in which R24 and R25 are hydrogen atoms and q is 2 or 3 from the viewpoint of charge / discharge cycle characteristics.

  Specific examples of the compound represented by the general formula (12) include ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, tetraethylene glycol divinyl ether, pentaethylene glycol divinyl ether, ethylene glycol propenyl vinyl ether, diethylene glycol propenyl vinyl ether. , Triethylene glycol propenyl vinyl ether, tetraethylene glycol propenyl vinyl ether, pentaethylene glycol propenyl vinyl ether, ethylene glycol dipropenyl ether, diethylene glycol dipropenyl ether, triethylene glycol dipropenyl ether, tetraethylene glycol dipropenyl ether and pentaethylene Etc. glycol dipropionate propenyl ether and the like. These can be obtained commercially.

  Specific examples of (D3) include cyclohexylpropenyl ether, 1,2-bis (propenoxymethyl) cyclohexane, 1,3-bis (propenoxymethyl) cyclohexane, 1,4-bis (propenoxymethyl) Cyclohexane, 1,3,5-tris (propenoxymethyl) cyclohexane, 1,2-bis (vinyloxymethyl) cyclohexane, 1,3-bis (vinyloxymethyl) cyclohexane, 1,4-bis (vinyloxymethyl) ) Cyclohexane and 1,3,5-tris (vinyloxymethyl) cyclohexane. These can be obtained commercially.

Modified polysiloxane (A), electrolyte dissociation accelerator (B), carbonate compound (C) based on the total weight of the electrolyte additive in the electrolyte additive of the present invention, and a compound having a vinyl ether group or propenyl ether group The preferred contents (% by weight) of (D) are as follows.
The content of (A) is preferably 0.1 to 100% by weight, and more preferably 0.8 to 8.7% by weight from the viewpoints of charge / discharge cycle characteristics and battery capacity. The content of (B) is preferably 0 to 97% by weight, and more preferably 17.9 to 82.3% by weight from the viewpoint of battery output. The content of (C) is preferably 0 to 90% by weight, more preferably 15.9 to 71.4% by weight from the viewpoint of battery capacity, battery output, and charge / discharge cycle characteristics. The content of (D) is preferably 0 to 50% by weight, and more preferably 0.4 to 4.3 parts by weight from the viewpoint of battery capacity, battery output, and charge / discharge cycle characteristics.

  The additive for electrolytic solution of the present invention is useful for forming a negative electrode protective film of a secondary battery. The additive for electrolytic solution of the present invention forms an electric double layer on the negative electrode in the secondary battery during initial charging, and forms a protective film by being subjected to reduction polymerization. By forming a protective film on the negative electrode, the nonaqueous solvent is prevented from being decomposed at the negative electrode, the output of the secondary battery is increased, and the charge / discharge cycle characteristics are prevented from being deteriorated.

  The electrolytic solution of the present invention contains a nonaqueous solvent, an electrolyte, and the additive for electrolytic solution.

  As the non-aqueous solvent, those used in ordinary electrolytic solutions can be used, for example, cyclic or chain carbonate ester, chain carboxylate ester, cyclic or chain ether, phosphate ester, lactone compound, nitrile compound. Amide compounds, etc., and mixtures thereof can be used. Examples of the cyclic carbonate include propylene carbonate, ethylene carbonate and butylene carbonate. Examples of the chain carbonate include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl-n-propyl carbonate, ethyl-n-propyl carbonate, and di-n-propyl carbonate. Examples of chain carboxylic acid esters include methyl acetate, ethyl acetate, propyl acetate, and methyl propionate. Examples of the cyclic ether include tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,4-dioxane and the like. Examples of the chain ether include dimethoxymethane and 1,2-dimethoxyethane. Examples of phosphate esters include trimethyl phosphate, triethyl phosphate, ethyl dimethyl phosphate, diethyl methyl phosphate, tripropyl phosphate, tributyl phosphate, tri (trifluoromethyl) phosphate, tri (trichloromethyl) phosphate, Tri (trifluoroethyl) phosphate, tri (triperfluoroethyl) phosphate, 2-ethoxy-1,3,2-dioxaphospholan-2-one, 2-trifluoroethoxy-1,3,2- Examples include dioxaphospholan-2-one and 2-methoxyethoxy-1,3,2-dioxaphosphoran-2-one. Examples of the lactone compound include γ-butyrolactone and γ-valerolactone. A nitrile compound includes acetonitrile. Examples of the amide compound include dimethylformamide. Of the nonaqueous solvents, cyclic carbonates, chain carbonates and phosphates are preferable from the viewpoint of battery output and charge / discharge recycling characteristics, and cyclic carbonates are more preferable.

  The content of the non-aqueous solvent is preferably 20 to 99% by weight and more preferably 58 to 93% by weight based on the weight of the electrolytic solution from the viewpoint of battery output and charge / discharge cycle characteristics.

  As the electrolyte contained in the electrolytic solution of the present invention, those used in ordinary electrolytic solutions can be used. For example, lithium salts of inorganic acids such as LiPF6, LiBF4, LiSbF6, LiAsF6 and LiClO4, LiN (CF3SO2) 2 , LiN (C2F5SO2) 2, LiC (CF3SO2) 3, and other organic acid lithium salts. Among these, LiPF6 is preferable from the viewpoint of battery output and charge / discharge cycle characteristics.

  The concentration of the electrolyte in the electrolytic solution is preferably 0.01 to 3 mol / L, more preferably 0.05 to 1.5 mol / L from the viewpoint of battery output and charge / discharge cycle characteristics, based on the capacity of the electrolytic solution. L.

  The addition amount of the additive for electrolytic solution of the present invention is preferably 0.1 to 10% by weight, more preferably 2 to 5% by weight, based on the total weight of the electrolytic solution. If the added amount is less than 0.1% by weight, a negative electrode protective film cannot be formed. If the added amount exceeds 10% by weight, the additive remaining in the electrolyte after charging is oxidatively decomposed at the positive electrode, resulting in battery characteristics. Is unfavorable because of lowering.

  You may add another additive to the electrolyte solution of this invention as needed. Examples of other additives include an overcharge inhibitor, a dehydrating agent, and a capacity stabilizer.

  Examples of the overcharge inhibitor include biphenyl, alkylbiphenyl, terphenyl, partially hydrogenated terphenyl, aromatic compounds such as cyclohexylbenzene, t-butylbenzene, and t-amylbenzene. The usage-amount of an overcharge inhibitor is 0-5 weight% normally based on the total weight of electrolyte solution, Preferably it is 1-3 weight%.

  Examples of the dehydrating agent include zeolite, silica gel and calcium oxide. The usage-amount of a dehydrating agent is 0-5 weight% normally based on the total weight of electrolyte solution, Preferably it is 1-3 weight%.

  Examples of the capacity stabilizer include fluoroethylene carbonate, succinic anhydride, 1-methyl-2-piperidone, heptane, and fluorobenzene. The amount of the capacity stabilizer used is usually 0 to 5% by weight, preferably 1 to 3% by weight, based on the total weight of the electrolytic solution.

  The method for preparing the electrolytic solution of the present invention is not particularly limited, and can be prepared by dissolving the electrolyte, the additive for electrolytic solution of the present invention, and other additives in a non-aqueous solvent. Moreover, it is preferable to dehydrate each raw material in advance when preparing the electrolytic solution so that the amount of water in the electrolytic solution is 50 ppm or less.

  Hereinafter, although an example and a manufacture example explain the present invention further, the present invention is not limited to these. In the following, “%” means “% by weight” and “parts” means “parts by weight”.

<Production Example 1>
Production of positive electrode;
After thoroughly mixing 9.0 parts of LiCoO2 powder, 0.5 part of Ketjen Black [manufactured by Aldrich] and 0.5 part of polyvinylidene fluoride [manufactured by Aldrich] in a mortar, 1-methyl-2-pyrrolidone [Tokyo [Made by Kasei Kogyo Co., Ltd.] 7.0 parts was added and further mixed well in a mortar to obtain a slurry. The obtained slurry was applied to one side of an aluminum electrolytic foil having a thickness of 20 μm using a wire bar in the atmosphere, dried at 100 ° C. for 15 minutes, and further under reduced pressure (10 mmHg) at 80 ° C. for 5 minutes. It dried and punched out to 15.95 mm diameter and produced the positive electrode with a film thickness of 30 micrometers.

<Production Example 2>
Production of negative electrode;
A slurry was obtained by sufficiently mixing 92.5 parts of graphite powder having an average particle size of about 8 to 12 μm, 7.5 parts of polyvinylidene fluoride and 200 parts of N-methylpyrrolidone [manufactured by Tokyo Chemical Industry Co., Ltd.] in a mortar. The obtained slurry was applied to one side of a 20 μm thick copper foil, dried at 100 ° C. for 15 minutes to evaporate the solvent, punched to 16.15 mmφ, and made a negative electrode with a thickness of 30 μm using a press. did.

<Production Example 3>
Production of secondary battery cells;
A positive battery and a negative electrode obtained in Production Examples 1 and 2 were arranged at both ends in the 2032 type coin cell so that the respective coated surfaces faced to produce a secondary battery cell.

<Production Example 4>
Synthesis of linear polysiloxane (hereinafter abbreviated as Si-1);
In a reaction vessel equipped with a stirrer, a thermometer and a reflux tube, 1.53-part (8.3 mmol) of (3-chloropropyl) methyldimethoxysilane (manufactured by Aldrich), dimethyldimethoxysilane (manufactured by Aldrich) 1.0 Part (8.3 mmol), 0.35 part (3.3 mmol) of trimethylmethoxysilane (manufactured by Aldrich) and 2.5 parts of methanol were cooled to −10 ° C., and 0.05 part of concentrated sulfuric acid was added. While cooling to −10 ° C., 0.3 part of ion-exchanged water was added dropwise over 30 minutes for hydrolysis. After stirring for 2 hours, the temperature was returned to room temperature, 5 parts of toluene was added, and the mixture was stirred for 30 minutes and allowed to stand for 2 hours. The upper layer of the two separated layers was taken out, and the solvent was distilled off under reduced pressure to obtain 1.52 parts of linear polysiloxane (Si-1) (yield 72.3%).

<Production Example 5>
Synthesis of cyclic polysiloxane (hereinafter abbreviated as Si-2);
In a reaction vessel equipped with a stirrer, a thermometer and a reflux tube, 1.53-part (8.3 mmol) of (3-chloropropyl) methyldimethoxysilane (manufactured by Aldrich), dimethyldimethoxysilane (manufactured by Aldrich) 1.0 Parts (8.3 mmol) and 2.5 parts of methanol were charged, cooled to −10 ° C., and 0.05 parts of concentrated sulfuric acid was added. While cooling to −10 ° C., 0.3 part of ion-exchanged water was added dropwise over 30 minutes for hydrolysis. After stirring for 2 hours, the temperature was returned to room temperature, 5 parts of toluene was added and stirred for 2 hours, then returned to room temperature, 5 parts of toluene was added, stirred for 30 minutes, and allowed to stand for 2 hours. The upper layer of the two separated layers was taken out, and the solvent was distilled off under reduced pressure to obtain 1.32 parts (yield 75.4%) of cyclic polysiloxane (Si-2).

<Production Example 6>
Synthesis of N- (4-vinylbenzyl) imidazole (hereinafter abbreviated as Im-1);
A reaction vessel equipped with a stirrer, a thermometer, and a cooling tube was charged with 1.0 part (14.7 mmol) of imidazole (manufactured by Aldrich), 10 parts of acetonitrile and 0.5 part of sodium carbonate, and chloromethylstyrene (Aldrich). (Manufactured) 2.24 parts (14.7 mmol) was added dropwise over 1 hour, followed by further stirring for 1 hour. After the solvent was distilled off under reduced pressure, the residue was purified by an alumina column (150 mesh, Blockman 1, standard grade, manufactured by Aldrich) using acetone as a solvent, and 2.43 parts of N- (4-vinylbenzyl) imidazole (Im-1) ( Yield 89.8%) was obtained.

<Production Example 7>
Synthesis of di (3,6-dioxaheptyl) (4-vinylbenzyl) amine (hereinafter abbreviated as Am-1);
In a reaction vessel equipped with a stirrer, a thermometer and a condenser, 1.0 part (5.2 mmol) of di (3,6-dioxaheptyl) amine (Aldrich), 10 parts of acetonitrile and 0.5% of sodium carbonate Then, 0.79 part (5.2 mmol) of chloromethylstyrene (manufactured by Aldrich) was added dropwise over 1 hour, followed by further stirring for 1 hour. After the solvent was distilled off under reduced pressure, the residue was purified by an alumina column (150 mesh, Blockman 1, standard grade, manufactured by Aldrich) using acetone as a solvent, and di (3,6-dioxaheptyl) (4-vinylbenzyl) amine (Am -1) 1.12 parts (yield 70.2%) were obtained.

<Production Example 8>
Synthesis of N- (methyl 2-butenoate) imidazole (hereinafter abbreviated as Im-2);
In a reaction vessel equipped with a stirrer, a thermometer and a condenser, 1.0 part (14.7 mmol) of imidazole (manufactured by Aldrich), 10 parts of acetonitrile and 0.5 part of sodium carbonate were charged, and 4-bromo-2- 2.63 parts (14.7 mmol) of butenoic acid methyl ester [manufactured by Tokyo Chemical Industry Co., Ltd.] was added dropwise over 1 hour, followed by further stirring for 1 hour. After the solvent was distilled off under reduced pressure, the residue was purified by an alumina column (150 mesh, Blockman 1, standard grade, manufactured by Aldrich) using acetone as a solvent, and 2.06 parts of N- (methyl 2-butenoate) imidazole (Im-2). (Yield 91.0%) was obtained.

<Production Example 9>
Synthesis of N- (2-acryloyloxypropyl) imidazole (hereinafter abbreviated as Im-3);
In a reaction vessel equipped with a stirrer, a thermometer and a condenser tube, 1.0 part (14.7 mmol) of imidazole (manufactured by Aldrich), 10 parts of acetonitrile and 0.5 part of sodium carbonate were charged, and 3-chloropropyl acrylate was added. [Tokyo Chemical Industry Co., Ltd.] 2.01 parts (14.7 mmol) was added dropwise over 1 hour, and the mixture was further stirred for 1 hour after the addition. After the solvent was distilled off under reduced pressure, the residue was purified by an alumina column (150 mesh, Blockman 1, standard grade, manufactured by Aldrich) using acetone as a solvent, and 2.16 parts of N- (2-acryloyloxypropyl) imidazole (Im-3). (Yield 87.6%) was obtained.

<Production Example 10>
Synthesis of N- (4-vinylbenzyl) imidazolium hexafluorophosphate-modified linear polysiloxane (hereinafter abbreviated as A-1); [In the general formula (1), R1, R2, R3, R4 and R5 = A methyl group, a and b = 5, c and d = 0, Q1 is a group represented by the general formula (3), R9 = hydrogen atom, X- is PF6-, and A1 is the general formula (6). A compound represented by R13 = methylene group, Q6, Q7, Q8 and Q9 = hydrogen atom]
In a reaction vessel equipped with a stirrer, a thermometer and a cooling tube, 1.0 part (0.6 mmol) of (Si-1) synthesized in Production Example 4, 10 parts of acetonitrile and Synthesis in Production Example 6 (Im-1) ) 0.58 parts (2.9 mmol) was charged and dissolved uniformly with stirring, and then reacted at room temperature for 24 hours with stirring. Next, 0.48 part (3.2 mmol) of LiPF6 [manufactured by Tokyo Chemical Industry Co., Ltd.] was added to the reaction mixture, and the mixture was further reacted for 24 hours. Acetonitrile was removed by reduced pressure (10 mmHg) and then purified by an alumina column (150 mesh, Blockman1, standard grade, manufactured by Aldrich) using acetone as a solvent to obtain 1.50 parts of (A-1) (yield 79). .5%).

<Production Example 11>
Synthesis of N, N, N-di (3,6-dioxaheptyl) (4-vinylbenzyl) ammonium hexafluorophosphate-modified linear polysiloxane (hereinafter abbreviated as A-2); [general formula (1 ), R1, R2, R3, R4 and R5 = methyl group, a and b = 5, c and d = 0, Q1 is a group represented by the general formula (4), R10 = ethylene group, R11 = Methyl group, g = 1, m = 2, Y- is PF6-, A2 is a group represented by the general formula (6), R13 = methylene group, Q6, Q7, Q8 and Q9 = hydrogen atom Some compounds]
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, 1.0 part (0.6 mmol) of (Si-1) synthesized in Production Example 4, 10 parts of acetonitrile, and Synthesis in Production Example 7 (Am-1) ) 0.90 part (2.9 mmol) was charged and dissolved uniformly with stirring, and then reacted at room temperature for 24 hours with stirring. To the reaction mixture, 0.48 part (3.2 mmol) of LiPF6 [manufactured by Tokyo Chemical Industry Co., Ltd.] was added, and the mixture was further reacted for 24 hours. Acetonitrile was removed by reduced pressure (10 mmHg), and then purified by an alumina column (150 mesh, Blockman 1, standard grade, manufactured by Aldrich) using acetone as a solvent to obtain 1.74 parts of (A-2) (yield 78 .6%).

<Production Example 12>
Synthesis of N- (4-vinylbenzyl) imidazolium hexafluorophosphite-modified cyclic polysiloxane (hereinafter abbreviated as A-3); [In the general formula (2), R6, R7 and R8 = methyl group, e = 5 , F = 5, Q2 is a group represented by the general formula (3), R9 = hydrogen atom, X- is PF6-, A1 is a group represented by the general formula (6), and R13 = Methylene group, Q6, Q7, Q8 and Q9 = compound in which hydrogen atom]
In a reaction vessel equipped with a stirrer, a thermometer, and a condenser, 1.0 part (0.6 mmol) of (Si-2) synthesized in Production Example 5, 10 parts of acetonitrile, and Synthesis in Production Example 6 (Im-1 ) 0.65 part (3.3 mmol) was charged and dissolved uniformly with stirring, and then reacted at room temperature for 24 hours with stirring. To the reaction mixture, 0.55 part (3.6 mmol) of LiPF6 [manufactured by Tokyo Chemical Industry Co., Ltd.] was added, and the mixture was further reacted for 24 hours. Acetonitrile was removed under reduced pressure (10 mmHg) and then purified by an alumina column (150 mesh, Blockman 1, standard grade, manufactured by Aldrich) using acetone as a solvent to obtain 1.79 parts of (A-3) (yield 88). .7%).

<Production Example 13>
Synthesis of N, N, N-di (3,6-dioxaheptyl) (4-vinylbenzyl) ammonium hexafluorophosphite modified cyclic polysiloxane (hereinafter abbreviated as A-4); [general formula (2) R6, R7 and R8 = methyl group, e = 5, f = 5, Q2 is a group represented by the general formula (4), R10 = ethylene group, R11 = methyl group, g = 1, m = 2, Compounds in which Y- is BF4-, A2 is a group represented by the general formula (6), and R13 = methylene group, Q6, Q7, Q8 and Q9 = hydrogen atom]
In a reaction vessel equipped with a stirrer, a thermometer and a cooling tube, 1.0 part (0.6 mmol) of (Si-2) synthesized in Production Example 5, 10 parts of acetonitrile, and Synthesis in Production Example 7 (Am-1) ) 1.02 part (3.3 mmol) was charged and dissolved uniformly with stirring, and then reacted at room temperature for 24 hours with stirring. To the reaction mixture, 0.55 part (3.6 mmol) of LiPF6 [manufactured by Tokyo Chemical Industry Co., Ltd.] was added, and the mixture was further reacted for 24 hours. Acetonitrile was removed by reduced pressure (10 mmHg) and then purified by an alumina column (150 mesh, Blockman 1, standard grade, manufactured by Aldrich) using acetone as a solvent to obtain 2.11 parts of (A-4) (yield 88). .6%).

<Production Example 14>
Synthesis of N- (methyl 2-butenoate) imidazolium hexafluorophosphate-modified linear polysiloxane (hereinafter abbreviated as A-5); [In the general formula (1), R1, R2, R3, R4 and R5 = Methyl group, a and b = 5, c and d = 0, Q1 is a group represented by the general formula (4), and R10 = ethylene group, R11 = methyl group, g = 1, m = 2, Compound in which Y- is a group represented by PF6-, A1 is represented by the general formula (5), R12 is a methylene group, Q3 and Q4 are hydrogen atoms, and Q5 is a methoxycarbonyl group.
In a reaction vessel equipped with a stirrer, a thermometer and a cooling tube, 1.0 part (0.6 mmol) of (Si-1) synthesized in Production Example 4, 10 parts of acetonitrile and Synthesis in Production Example 8 (Im-2) ) 0.45 part (3.3 mmol) was charged and dissolved uniformly with stirring, and then reacted at room temperature for 24 hours with stirring. To the reaction mixture, 0.55 part (3.6 mmol) of LiPF6 [manufactured by Tokyo Chemical Industry Co., Ltd.] was added, and the mixture was further reacted for 24 hours. Acetonitrile was removed under reduced pressure (10 mmHg) and then purified by an alumina column (150 mesh, Blockman 1, standard grade, manufactured by Aldrich) using acetone as a solvent to obtain 1.51 parts of (A-5) (yield 85). .3%).

<Production Example 15>
Synthesis of N- (2-acryloyloxypropyl) imidazolium hexafluorophosphite-modified cyclic polysiloxane (hereinafter abbreviated as A-6); [in the general formula (2), R6, R7 and R8 = methyl group, e = 5, f = 5, Q2 is a group represented by the general formula (4), R10 = ethylene group, R11 = methyl group, g = 1, m = 2, Y- is PF6-, and A2 is acryloyl. Compound that is oxypropyl group]
In a reaction vessel equipped with a stirrer, a thermometer and a cooling tube, 1.0 part (0.6 mmol) of (Si-2) synthesized in Production Example 5, 10 parts of acetonitrile, and Synthesis in Production Example 9 (Im-3) ) 0.49 parts (3.3 mmol) was charged and dissolved uniformly with stirring, and then reacted at room temperature for 24 hours with stirring. To the reaction mixture, 0.55 part (3.6 mmol) of LiPF6 [manufactured by Tokyo Chemical Industry Co., Ltd.] was added, and the mixture was further reacted for 24 hours. Acetonitrile was removed by reduced pressure (10 mmHg) and then purified by an alumina column (150 mesh, Blockman 1, standard grade, manufactured by Aldrich) using acetone as a solvent to obtain 1.57 parts of (A-6) (yield 86 .9%).

<Examples 1 to 23>
Adjustment of electrolyte additives;
Each raw material of the additive for electrolyte solution described in Table 1 and Table 2 was mix | blended, and the additive for electrolyte solution (Examples 1-19) was produced. In addition, the following were used for each raw material described in Table 1 and Table 2.
(B-1): Dimethoxyethane (number of donors = 24)
(B-2): Diethylene glycol diethyl ether (donor number = 22)
(B-3): Triethylene glycol diethyl ether (donor number = 25)
(B-4): Decaethylene glycol dipentyl ether (number of donors = 25)
(B-5): Dimethyl sulfoxide (number of donors = 30)
(B-6): Dibutyl sulfoxide (donor number = 27)
(C-1): Vinylene carbonate (C-2): Di-n-propyl vinylene carbonate (C-3): Vinyl ethylene carbonate (C-4): Divinyl carbonate (D-1): 1,4-butanediol di Vinyl ether (D-2): Diethylene glycol divinyl ether (D-3): 1,4-bis (vinyloxymethyl) cyclohexane

<Examples 20 to 38>
Adjustment of the electrolyte;
An electrolyte solution was prepared by dissolving LiPF6 as an electrolyte in a mixed solvent of ethylene carbonate: diethyl carbonate = 1: 1 (weight ratio) to a concentration of 1 mol / L. To the obtained electrolyte solution, (X-1) to (X-19) obtained in Examples 1 to 19 were added so as to have the addition amounts shown in Table 3 and Table 4, respectively, until uniform and transparent. Stirring and adjusting the electrolyte solutions of Examples 20-40.

<Comparative Example 1>
The electrolyte solution of Comparative Example 1 was obtained using the electrolyte solution as it was (without adding an additive for electrolyte solution).

<Comparative example 2>
To 97 parts of the electrolyte solution, 3 parts of vinylene carbonate (VC) was added and stirred until uniform and transparent to prepare the electrolyte solution of Comparative Example 2.

  The electrolytic solutions prepared in Examples 20 to 40 and Comparative Examples 1 to 3 were sealed after being poured into secondary battery cells, respectively, and the battery output, charge / discharge cycle characteristics under high temperature and overcharge conditions were as follows. The charge / discharge cycle characteristics below were measured. The results are shown in Tables 3 and 4.

<Evaluation of battery output>
Using a charge / discharge measurement device “Battery Analyzer 1470” [manufactured by Toyo Technica Co., Ltd.], charge so that SOC (State of charge, the ratio of the capacity in a fully charged state to the capacity at a predetermined time) is 60%. Then, discharge at a constant current and read the voltage after 10 seconds. This operation is performed with several current values, and the current value is plotted on the horizontal axis and the voltage value after 10 seconds is plotted on the vertical axis to create an approximate line, and the current value (I3. The battery output is calculated from the following formula.
Battery output (W) = I3.0V × 3.0

<Evaluation of charge / discharge cycle characteristics at high temperature>
After putting the cell in a constant temperature bath at 50 ° C., using a charge / discharge measuring device “Battery Analyzer 1470 type” [manufactured by Toyo Technica Co., Ltd.], the battery is charged from 0 V to 2 V with a current of 0.2 mA / cm 2, After 10 minutes of rest, the battery voltage was discharged to 0 V with a current of 0.2 mA / cm2, and this charge / discharge was repeated. At this time, the battery capacity at the first charge and the battery capacity at the 500th charge are measured, and the charge / discharge cycle characteristics are calculated from the following equation. It shows that charging / discharging cycling characteristics are so favorable that a numerical value is large.
Charging / discharging cycle characteristics at high temperature (%)
= (Battery capacity at 500th cycle charge / Battery capacity at first charge) × 100

<Evaluation of charge / discharge cycle characteristics under overcharge conditions>
The cycle characteristics under overcharge conditions were evaluated by increasing the charge / discharge current. Using a charge / discharge measuring device “Battery Analyzer 1470 type” [manufactured by Toyo Technica Co., Ltd.], the battery was charged from 0 V to 2 V with a current of 0.8 mA / cm 2, and after resting for 10 minutes, 0.8 mA / cm 2 The battery voltage was discharged to 0 V with current, and this charge / discharge was repeated. At this time, the battery capacity at the first charge and the battery capacity at the 500th charge are measured, and the charge / discharge cycle characteristics are calculated from the following equation. It shows that charging / discharging cycling characteristics are so favorable that a numerical value is large.
Charging / discharging cycle characteristics (%) under overcharge conditions
= (Battery capacity at 500th cycle charge / Battery capacity at first charge) × 100

  The lithium secondary battery produced using the electrolyte solution additive of the present invention has a high battery output and excellent charge / discharge cycle characteristics under high temperature and overcharge conditions. The reason for the high output is considered to be that a polysilicon film having high lithium ion conductivity is formed on the negative electrode surface. The reason why the charge / discharge cycle characteristics are improved under high temperature and overcharge conditions is considered to be that the composition of the protective film is a polysilicon having excellent heat resistance and voltage resistance.

  When the additive for electrolytic solution of the present invention is added to a secondary battery, the battery output and charge / discharge cycle characteristics are improved. Therefore, the additive for electrolytic solution is useful as an additive for electrolytic solution of a secondary battery for mobile phones, personal computers, hybrid vehicles, etc It is. Further, it can be applied to a protective film for a positive electrode and an electrode protective film for a lithium ion capacitor.

Claims (16)

  An electrolytic solution comprising a modified polysiloxane having a nitrogen atom constituting an onium salt, wherein the nitrogen atom is bonded to an organic group (a) having a polymerizable unsaturated bond. Additives. The electrolyte solution additive according to claim 1, further comprising an electrolyte dissociation accelerator (B). Furthermore, the additive for electrolyte solutions containing the carbonate compound (C) which has a polymerizable unsaturated bond. Furthermore, the additive for electrolyte solutions in any one of Claims 1-3 formed by containing the compound (D) which has a vinyl ether group or a propenyl ether group. The additive for electrolytic solution according to any one of claims 1 to 4, wherein the modified polysiloxane is a modified polysiloxane represented by the general formula (1).

[Wherein R1, R2, R3, R4 and R5 are each independently at least one group selected from the group consisting of an alkyl group, a halogenated alkyl group, an aryl group, an aralkyl group, an alkoxy group and an aryloxy group. Q1 is a group having a nitrogen atom and a polymerizable unsaturated bond constituting an onium salt, a is a number from 0 to 200, b is a number from 4 to 200, and c and d are each independently 0 or 1. ] The additive for electrolyte solution according to any one of claims 1 to 4, wherein the modified polysiloxane is a polysiloxane represented by the general formula (2).

Wherein R6, R7 and R8 are each independently at least one selected from the group consisting of an alkyl group, a halogenated alkyl group, an aryl group, an aralkyl group, an alkoxy group and an aryloxy group, and Q2 is an onium A group having a nitrogen atom and a polymerizable unsaturated bond constituting the salt, e is a number of 0 to 100, f is a number of 1 to 100, and e + f is 7 to 200. ]   The additive for an electrolytic solution according to any one of claims 1 to 6, wherein the onium salt is an imidazolium salt and / or a quaternary ammonium salt. The additive for electrolytic solution according to claim 5 or 6, wherein Q1 in the general formula (1) or Q2 in the general formula (2) is a group represented by the general formula (3).

[Wherein R9 represents a hydrogen atom, a methyl group or an ethyl group, A1 represents an organic group (a) having a polymerizable unsaturated bond, and X- represents an anion. ] The additive for electrolytic solution according to claim 5 or 6, wherein Q1 in the general formula (1) or Q2 in the general formula (2) is a group represented by the general formula (4).

[Wherein R10 is an alkylene group having 2 to 4 carbon atoms, R11 is an alkyl group having 1 to 3 carbon atoms, A2 is an organic group (a) having a polymerizable unsaturated bond, m is a number of 1 to 5, g Represents an integer of 1 to 3, and Y- represents an anion. ] The addition for electrolyte solution according to claim 8 or 9, wherein the organic group (a) is a group represented by the general formula (5), a group represented by the general formula (6), or a (meth) acryloyloxyalkyl group. Agent.

[Wherein R12 is an alkylene group having 1 to 3 carbon atoms, and Q3, Q4 and Q5 are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a halogen atom, a fluoroalkyl group, A cyano group, a carboxyl group, an alkoxy group or an alkoxycarbonyl group; ]

[Wherein R13 is an alkylene group having 1 to 3 carbon atoms, Q6 is a hydrogen atom or a halogen atom, and Q7, Q8 and Q9 are each independently a hydrogen atom and an alkyl group having 1 to 4 carbon atoms. , Phenyl group, halogen atom, fluoroalkyl group, cyano group, carboxyl group, alkoxy group or alkoxycarbonyl group. ]   The electrolyte solution additive according to any one of claims 2 to 10, wherein the electrolyte dissociation accelerator (B) is a sulfoxide compound having a donor number of 16 to 40 and / or an ether compound having a donor number of 16 to 40. The additive for electrolytic solution according to claim 11, wherein the sulfoxide compound is a sulfoxide compound represented by the general formula (7).

[In formula, R14 and R15 are respectively independently a C1-C5 alkyl group. ] The additive for electrolytic solution according to claim 11, wherein the ether compound is an ether compound represented by the general formula (8).
R16-O- (CH2CH2O) n-R17 (8)
[In formula, R16 and R17 are respectively independently a C1-C5 alkyl group, and n is a number of 1-10. ] The additive for electrolytic solution according to any one of claims 3 to 13, wherein the carbonate compound (C) is a compound represented by the general formula (9) and / or a compound represented by the general formula (10).

[In formula, R18 and R19 are respectively independently a hydrogen atom or a C1-C3 alkyl group. ]

[Wherein, R20 and R21 are each independently a hydrogen atom or an alkenyl group having 2 to 3 carbon atoms, and R20 and R21 are not both hydrogen atoms. ] The compound (D) is a cyclohexane derivative having one or more vinyl ether groups or propenyl ether groups, a compound represented by the general formula (11), or a compound represented by the general formula (12). The additive for electrolyte solutions in any one.
R22-CH = CH-O- (CH2) p-O-CH = CH-R23 (11)
[In formula, R22 and R23 are respectively independently a hydrogen atom or a methyl group, and p is a number of 4-10. ]
R24—CH═CH—O— (C2H4O) q—O—CH═CH—R25 (12)
[In formula, R24 and R25 are respectively independently a hydrogen atom or a methyl group, and q is a number of 1-5. ]   An electrolytic solution comprising a nonaqueous solvent, an electrolyte, and the additive for electrolytic solution according to claim 1.