JP5875954B2 - Cyanoborate compound and electrolyte using the same - Google Patents

Description

  The present invention relates to a cyanoborate compound and an electrolyte using the same.

  An ionic compound and an electrolyte material containing the ionic compound are used for ion conductors such as various types of batteries by ion conduction. In addition to a battery having a charge / discharge mechanism such as a primary battery, a lithium ion secondary battery, and a fuel cell, an electric field is used. It is used for electrochemical devices such as capacitors, electric double layer capacitors, lithium ion capacitors, solar cells, and electrochromic display elements.

  Various ionic compounds that are suitably used for these electrochemical devices have been studied, such as hexafluorophosphate, tetrafluoroborate, trifluoromethylsulfonylimide (TFSI), dicyanoamide (DCA), Alkali metal salts or organic cation salts such as tricyanomethide (TCM) have been proposed.

In particular, with respect to an ionic compound having cyanoborate whose central element is boron as an anion, for example, Patent Documents 1 and 2 disclose tetracyanoborate ([B ⁻ (CN) ₄ ], hereinafter sometimes referred to as TCB). An ionic compound (TCB salt) in which is an anion is described. Since the TCB salt has properties as an ionic liquid, that is, it is liquid even at room temperature and is stable in terms of thermal, physical and electrochemical properties, it can be used for various purposes in addition to its production method. Applications have been studied (Patent Documents 1 and 2).

  Patent Document 3 discloses an ionic compound in which a part of a cyano group bonded to boron of TCB is substituted with an alkoxy group or a thioalkoxy group, and the ionic compound is useful as an ionic liquid or the like. It is described that.

JP-T-2006-517546 International Publication No. 2010/021391 Pamphlet International Publication No. 2010/086131 Pamphlet

  For example, as an application of the ionic compound, a cell phone, a personal computer, a household appliance, and an electricity storage device used for a power source of an automobile or the like are being studied. In these applications, demands for downsizing and high performance are increasing year by year, and power storage devices are required to have high output and to maintain stable capacity over a long period of time.

  For the improvement of the performance of the electricity storage device, an ionic compound may be considered. That is, if the cyanoborate substituent can be converted to an arbitrary substituent, the properties such as the melting point and solubility in an organic solvent can be changed according to the application while having the properties as a TCB. Therefore, it is considered that it is possible to provide an appropriate ionic compound.

  The present invention has been made by paying attention to the above-described circumstances, and as an electrolyte that enables high-output, long-term stable capacity maintenance in an electricity storage device by examining various substituents of cyanoborate. It is an object to provide a novel cyanoborate compound that can be suitably used. The present invention also provides an electrolyte using the same.

  As a result of various studies on cyanoborate compounds, the present inventors have found a novel cyanoborate compound having a specific substituent, and have found that the cyanoborate compound can be suitably used as an electrolyte for an electricity storage device. The cyanoborate of the present invention is characterized in that it is a cyanoborate compound represented by the general formula (1).

(In the formula, M ^{m +} represents a proton (H ⁺ ), a monovalent, divalent, or trivalent organic or inorganic cation, and Y represents the number of carbon atoms in the main chain which may have H, halogen, or halogen. 1 to 10 hydrocarbon group, cyano group, —C (O) R ¹⁴ , —S (O) ₁ R ¹⁴ , Z (R ¹⁴ ) ₂ or XR ¹⁴ , wherein R ¹⁴ represents H, halogen, or The main chain represents an organic substituent having 1 to 10 atoms, Z represents N or P, X represents O or S, l represents an integer of 1 to 2, and m represents an integer of 1 to 3. And n represents an integer of 0 to 10.)

In the ionic compound according to the present invention, in the general formula (1), Y is more preferably a cyano group or a halogen. In the general formula (1), an ionic compound in which M ^{m +} is a metal ion and an ionic compound in which the M ^{m +} is an organic cation are both preferred embodiments of the present invention.
The present invention also includes a composition containing a cyanoborate compound represented by the general formula (1) and a medium, and an electrolyte containing the cyanoborate compound.

  The cyanoborate compound according to the present invention has a structure in which a cyano group, an ester bond, and a substituent Y are bonded to boron, and has a different structure from a TCB salt in which only a cyano group is bonded directly to boron. It is expected to have different physical properties from TCB salts in terms of solubility in organic solvents. In addition, it is predicted that the ester bond bonded to boron is appropriately decomposed, and by using an electrolytic solution containing this cyanoborate salt as an electrolyte for various power storage devices, a film is formed on the electrode surface of the power storage device, It can be expected that decomposition of additives contained in the electrolytic solution is suppressed and stable capacity maintenance is exhibited. In addition, the presence of the cyano group can be expected to improve the working voltage band due to the improvement of the withstand voltage, similar to the TCB salt.

FIG. 1 is a diagram showing LSV measurement results of lithium cyano (fluoro) oxalatoborate. FIG. 2 is a diagram showing LSV measurement results of lithium dicyanooxalatoborate. FIG. 3 is a diagram showing LSV measurement results of lithium difluorooxalatoborate.

1. Cyanoborate Compound The ionic compound according to the present invention has the general formula (1):

Is a cyanoborate compound represented by the following (hereinafter referred to as compound (1)). In the above formula (1), M ^{m +} represents a proton, monovalent, divalent, or trivalent organic or inorganic cation, and Y represents the number of carbons in the main chain which may have H, halogen, or halogen. Represents a hydrocarbon group of 1 to 10, a cyano group, —C (O) R ¹⁴ , —S (O) ₁ R ¹⁴ , —Z (R ¹⁴ ) ₂ or —XR ¹⁴ , wherein R ¹⁴ represents H, halogen Or an organic substituent having 1 to 10 atoms in the main chain, Z represents N or P, X represents O or S, l represents an integer of 1 to 2, and m represents 1 to 3 N represents an integer of 0 to 10.

  In the cyanoborate compound (1) according to the present invention, the cyanoborate anion constituting the compound (1) has two ester-bonded substituents bonded to boron, and is bonded to each other to form a ring. It is characterized in that That is, while the TCB salt has a structure in which only a cyano group is bonded directly to boron, the compound (1) according to the present invention has a structure in which a cyano group, an ester bond, and a substituent Y are bonded to boron. doing. Therefore, from the difference in structure, it is expected to have physical properties different from those of the TCB salt in terms of melting point and solubility in organic solvents. In addition, it is predicted that the ester bond bonded to boron is appropriately decomposed. By using an electrolytic solution containing this cyanoborate salt as an electrolyte for various power storage devices, a film is formed on the electrode surface of the power storage device, and the solvent or the electrolyte It can be expected that the decomposition of additives contained therein is suppressed and stable capacity maintenance is exhibited. In addition, the presence of the cyano group can be expected to improve the working voltage band due to the improvement of the withstand voltage, similar to the TCB salt. Hereinafter, the anion and cation constituting the ionic compound according to the present invention will be described in order.

1-1. Cyanoborate anion In the cyanoborate anion represented by the above general formula (1), n represents an integer of 0 to 10, and is a direct bond or carbon of a methylene group in which two ester bonds bonded to boron are bonded to each other. Indicates a number. n is preferably 0 to 4, more preferably 0 to 2.

Accordingly, as the cyanoborate anion of the present invention, cyanooxalatoborate (n = 0), cyanomalonatoborate (n = 1), cyanosuccinateborate (n = 2), cyanoglutaratoborate (n = 3) And cyano adipolato borate (n = 4). In the cyanoborate anion represented by the above general formula, Y is H, halogen, a hydrocarbon group having 1 to 10 carbon atoms in the main chain which may have halogen, a cyano group, -C (O) R. ¹⁴ , -S (O) ₁ R ¹⁴ , -Z (R ¹⁴ ) ₂ or -XR ¹⁴ is represented.

  When the substituent Y constituting the cyanoborate anion is halogen, Y includes F, Cl, Br, or I. Among halogens, F (fluorine) is preferable because of its high affinity with boron atoms and stable BF bond.

  When the substituent Y is a hydrocarbon group having 1 to 10 carbon atoms in the main chain, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, sec- C 1-10 alkyl groups such as butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl; vinyl, propenyl, isopropenyl, allyl, 1- Carbon such as butenyl group, 2-butenyl group, 3-butenyl group, 1,3-butadienyl group, 1-cyclohexenyl group, 2-cyclohexenyl group, 3-cyclohexenyl group, methylcyclohexenyl group, ethylcyclohexenyl group An alkenyl group having 1 to 10 carbon atoms; an alkynyl having 1 to 10 carbon atoms such as an ethynyl group, a propargyl group, a cyclohexylethynyl group, and a phenylethynyl group; ; Include; phenyl group, a benzyl group, a thienyl group, a pyridyl group, an aryl group or a hetero atom-containing aryl group having 6 to 10 carbon atoms such as an imidazolyl group.

  Examples of the halogenated hydrocarbon group having 1 to 10 carbon atoms in the main chain include a fluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a chloromethyl group, a bromomethyl group, an iodomethyl group, a difluorochloromethyl group, and a fluorodichloromethyl group. , Fluoroethyl group, difluoroethyl group, trifluoroethyl group, tetrafluoroethyl group, perfluoroethyl group, fluorochloroethyl group, chloroethyl group, fluoropropyl group, perfluoropropyl group, fluorochloropropyl group, perfluorobutyl group Perfluorooctyl group, pentafluorocyclohexyl group, perfluorocyclohexyl group, pentafluorophenyl group, perchlorophenyl group, fluoromethylene group, fluoroethylene group, fluorocyclohexene group, etc. Some or all of the hydrogen atoms halogenated halogenated alkyl group or halogenated aryl groups substituted with (F, Cl, Br or I).

The hydrocarbon group Y having 1 to 10 carbon atoms in the main chain which may have a halogen has a substituent (for example, an alkoxy group, an amino group, a cyano group, a carbonyl group, a sulfonyl group, etc.). May be. Moreover, you may have a functional group containing hetero atoms, such as Si, B, O, N, and Al. Examples of the functional group containing a hetero atom include a cyano group, a trimethylsilyl group, a triethylsilyl group, a dimethoxyaluminum group, —CH ₂ CH ₂ B (CN) ₃ , —C ₃ H ₆ B (CN) _{3 and the} like. . When the substituent Y contains an electroattractive substituent such as a cyano group, the withstand voltage of the cyanoborate salt is expected to be high, which is preferable.

  As described above, when Y is a hydrocarbon group having 1 to 10 carbon atoms in the main chain which may have a halogen, the solubility of the cyanoborate salt in an organic solvent is improved. When used as an electrolytic solution, a high-performance electrolytic solution can be obtained, which is preferable.

In the above -C (O) R ¹⁴ , -S (O) ₁ R ¹⁴ , -Z (R ¹⁴ ) ₂ and -XR ¹⁴ , R ¹⁴ is H, halogen, or the number of atoms of the main chain is 1 to 10 Represents an organic substituent. As the halogen, fluorine, chlorine, bromine, iodine or the like is preferable. The organic substituent may be linear, branched or cyclic, and may have two or more of these structures, or may have a substituent. Furthermore, the organic substituent R ¹⁴ may contain an unsaturated bond. The number of atoms in the main chain of the organic substituent R ¹⁴ is as described above, but the number of carbons (including the substituent) contained in the organic substituent R ¹⁴ is preferably in the range of 1 to 20, more preferably. Is in the range of 1-10. The organic substituent R ¹⁴ may contain heteroatoms (O, N, S, Si, etc.) other than carbon and hydrogen, and halogen atoms (F, Cl, Br, etc.). There is no particular limitation. Therefore, for example, in the case of Y in the general formula (1), when Y is XR ¹⁴ , the type of atoms adjacent to X is not particularly limited to carbon, and is, for example, a heteroatom such as Si or Al. May be. Further, the organic substituent R ¹⁴ may be composed only of atoms other than carbon.

Specific examples of the organic substituent R ¹⁴ include organic groups including saturated hydrocarbon groups, unsaturated hydrocarbon groups, halogenated hydrocarbon groups, cyanated hydrocarbon groups, alkoxylated and / or aryloxylated hydrocarbon groups, and alkanoyl groups. Substituent, organic substituent having an ester bond, nitrogen-containing organic substituent, group having a thioalkoxy structure, organic substituent having a sulfinyl group, organic substituent having a sulfonyl group, organic substituent having a hetero atom, -CH ₂ CH ₂ OB (CN) ₃ , —C ₃ H ₆ OB (CN) ₃ ; The organic substituent R ¹⁴ may include linear, branched, cyclic, or a combination thereof.

If the Y is represented by -C (O) R ¹⁴ is, R ¹⁴ is a hydrocarbon group or a halogenated hydrocarbon group of saturated or unsaturated, alkoxylated or aryloxy hydrocarbon group, or a nitrogen-containing An organic substituent is preferable, and R ¹⁴ is more preferably a methyl group, an ethyl group, a phenyl group, a trifluoromethyl group, or a pentafluorophenyl group. Therefore, as the substituent Y, acetyl group, propanoyl group, butanoyl group, pentanoyl group, hexanoyl group, heptanoyl group, octanoyl group, isobutanoyl group, trifluoroacetyl group, benzoyl group, pentafluorobenzoyl group, acryloyl group, methacryloyl group Including linear, branched, cyclic, or combinations thereof, such as methyl oxalyl group (—COCOCH ₃ ), methyl malonyl group (—COCH ₂ COCH ₃ ), methyl succinyl group (—COCH ₂ CH ₂ COCH ₃ ) Organic substituents including alkanoyl groups, acetoxymethylcarbonyl group, acetoxyethylcarbonyl group, benzoyloxyethylcarbonyl group, methoxycarbonyl group, ethoxycarbonyl group, methoxyethyleneoxycarbonyl group, etc., linear, branched, ring Alternatively, an organic substituent having an ester bond including a combination thereof; a nitrogen-containing organic substituent including a linear, branched, cyclic, or combination thereof, such as an amide group, an N-alkylamide group, and an N-phenylamide group; Can be mentioned.

When Y is represented by —S (O) ₁ R ¹⁴ , R ¹⁴ is preferably a halogen, a saturated or unsaturated hydrocarbon group or a halogenated hydrocarbon group, more preferably a halogen, A halogenated hydrocarbon group; Specifically, as —S (O) ₁ R ¹⁴ , a fluorosulfinyl group, a chlorosulfinyl group, a trifluoromethylsulfinyl group, a pentafluoroethylsulfinyl group, a phenylsulfinyl group, a pentafluorophenylsulfinyl group, a tolylsulfinyl group, etc. Sulfonyl groups (l = 1), fluorosulfonyl groups, chlorosulfonyl groups, trifluoromethylsulfonyl groups, pentafluoroethylsulfonyl groups, tolylsulfonyl groups, phenylsulfonyl groups, pentafluorophenylsulfonyl groups and the like (l = 2) ) Is more preferable.

-C (O) R ¹⁴ and -S (O) ₁ R ¹⁴ are electron-withdrawing substituents like the cyano group and delocalize the negative charge charged in the central element. Therefore, the withstand voltage can be expected to be improved similarly to the cyano group.

When Y is represented by —Z (R ¹⁴ ) ₂ , amino groups such as dimethylamino group and ethylmethylamino group where Z is N; Z such as diphenylphosphino group and dicyclohexylphosphino group is P A certain phosphino group;

When Y is represented by —XR ¹⁴ , X is O, and R ¹⁴ may have a halogenated hydrocarbon group having 1 to 20 carbon atoms (for example, methyl group, ethyl group, phenyl group) A group that is a saturated hydrocarbon group or an unsaturated hydrocarbon group such as a pentafluorophenyl group, a trifluoromethyl group, or a pentafluoroethyl group); X is O, and R ¹⁴ is an alkylsilyl group (for example, trimethylsilyl) An alkanoyl group (for example, an acetyl group, a triethylsilyl group, etc.) selected from X, O, and R ¹⁴ is monovalent, linear, branched, cyclic, or a combination thereof. Fluoroacetyl, propanoyl, butanoyl, pentanoyl, hexanoyl, heptanoyl, octanoyl, isopropanoyl, isobutanoyl, benzoyl, pentaf Orobenzoiru group, an acryloyl group, a methacryloyl group, methyl oxalyl group, methylmalonyl group, group a Mechirusukushiniru group); a X is O, R ¹⁴ is a sulfinyl group (e.g., fluoro-sulfinyl group, chloro sulfinyl group, A trifluoromethylsulfinyl group, a tolylsulfinyl group, etc.) or a sulfonyl group (fluorosulfonyl group, chlorosulfonyl group, trifluoromethylsulfonyl group, tolylsulfonyl group, etc.); X is S, and R ¹⁴ is Groups (for example, a methylthio group, a trifluoromethylthio group, etc.) which are C1-C20 hydrocarbon groups which may have a halogen, etc. are mentioned. X is O or S, but X is preferably O from the viewpoint of easy availability of raw materials and cost.

When Z (R ¹⁴ ) ₂ or XR ¹⁴ is introduced into the cyanoborate salt, it becomes a salt with excellent withstand voltage as well as high withstand voltage. In this case, it is preferable that R ¹⁴ contains an electron-withdrawing substituent because the voltage resistance of the cyanoborate anion increases. Specifically, R ¹⁴ preferably contains an alkanoyl group, a sulfinyl group, or a sulfonyl group. Similarly, R ¹⁴ is preferably fluorine or a group containing fluorine such as a fluoroalkyl group.

  The anion of the cyanoborate compound of the present invention may be cyanoborate anions represented by the following general formulas (8-1) and (8-2).

(In the general formulas (8-1) and (8-2), X is O and p is an integer of 0 to 10. Preferably, X is O, p is 0 to 4, and p is 0. More preferably, it is ~ 1.)

  More specific examples of the anion of the cyanoborate compound of the present invention include those represented by the following formulas (10-1) to (10-14) (n is an integer of 0 to 2, 1 is preferable, and 0 is more preferable. Preferred anions include (10-1), (10-2), (10-3), (10-4), (10-7), (10-9) and (10-10).

1-2. Proton (H ⁺ ), organic or inorganic cation; M ^{m +}
The organic cation M ^{m +} constituting the ionic compound according to the present invention is represented by the general formula (2): L ⁺ -R _S (wherein L represents C, Si, N, P, S or O, R Are the same or different organic groups and may be bonded to each other, s represents the number of R bonded to L, and is 2, 3 or 4. Note that s is the valence of element L and L The onium cation represented by the number of double bonds directly bonded to is preferable.

  The “organic group” represented by R means a group having at least one hydrogen atom, fluorine atom, or carbon atom. The “group having at least one carbon atom” only needs to have at least one carbon atom, and may have another atom such as a halogen atom or a hetero atom, a substituent, or the like. Good. Examples of the substituent include amino group, imino group, amide group, ether bond group, thioether bond group, ester group, hydroxyl group, alkoxy group, carboxyl group, carbamoyl group, cyano group, disulfide group, nitro group. Group, nitroso group, sulfonyl group and the like.

  Examples of the onium cation represented by the general formula (2) include those represented by the following general formula.

(R in the formula is the same as in the general formula (2))

  Among the six onium cations represented by the above general formula, those in which L is N, P, S or O are more preferable, and onium cations in which L is N are more preferable. The said onium cation may be used independently and may use 2 or more types together. Specifically, examples of the onium cation in which L is N, P, S, or O include those represented by the following general formulas (3) to (5).

  General formula (3):

At least one of 15 types of heterocyclic onium cations represented by the formula:

Examples of the organic groups R ^{1 to} R ⁸ include the same organic groups R exemplified in the general formula (2). More specifically, R ^{1 to} R ⁸ are a hydrogen atom, a fluorine atom, or an organic group, and examples of the organic group include a straight chain, a branched chain, or a ring (provided that R ^{1 to} R ⁸ are bonded to each other to form a ring). Are preferably a hydrocarbon group having 1 to 18 carbon atoms or a fluorine group, and more preferably a hydrocarbon group having 1 to 8 carbon atoms or a fluorine group. Moreover, the organic group may contain the substituent illustrated about the said General formula (2), hetero atoms, such as N, O, and S, and a halogen atom.

  General formula (4):

(Wherein R ^{1 to} R ¹² are the same as R ^{1 to} R ^{8 in} the general formula (3))
At least one of nine types of saturated ring onium cations represented by the formula:

  General formula (5):

(Wherein R ^{1 to} R ⁴ are the same as R ^{1 to} R ^{8 in} the general formula (3))
A chain onium cation represented by

For example, as the chain onium cation represented by the general formula (5), tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, tetraheptylammonium, tetrahexylammonium, tetraoctylammonium, triethylmethylammonium, methoxy Ethyl diethylmethylammonium, trimethylphenylammonium, benzyltrimethylammonium, benzyltriethylammonium, benzyltributylammonium, dimethyldistearylammonium, diallyldimethylammonium, 2-methoxyethoxymethyltrimethylammonium and tetrakis (pentafluoroethyl) ammonium, N-methoxytrimethyl Ammonium, N-ethoxylate Quaternary ammoniums such as methylammonium and N-propoxytrimethylammonium, tertiary ammoniums such as trimethylammonium, triethylammonium, tributylammonium, diethylmethylammonium, dimethylethylammonium and dibutylmethylammonium, dimethylammonium and diethylammonium, Secondary ammoniums such as dibutylammonium, primary ammoniums such as methylammonium, ethylammonium, butylammonium, hexylammonium and octylammonium, and ammonium compounds represented by NH ₄ are included.

  Among the onium cations of the above general formulas (3) to (5), an onium cation containing a nitrogen atom is more preferable, and a more preferable one is the following general formula:

(Wherein, R ¹ to R ¹² are the same as R ¹ to R ⁸ of general formula (3).)
And at least one of six kinds of onium cations represented by the formula:

  Among the six kinds of onium cations, chain quaternary ammonium such as tetraethylammonium, tetrabutylammonium and triethylmethylammonium, chained tertiary ammonium such as triethylammonium, tributylammonium, dibutylmethylammonium and dimethylethylammonium, Pyrrolidiniums such as 1-ethyl-3-methylimidazolium and imidazolium such as 1,2,3-trimethylimidazolium, N, N-dimethylpyrrolidinium and N-ethyl-N-methylpyrrolidinium are readily available. It is more preferable because it exists. More preferred are quaternary ammonium and imidazolium. From the viewpoint of reduction resistance, quaternary ammonium such as tetraethylammonium, tetrabutylammonium and triethylmethylammonium classified into the chain onium cation is more preferable.

Examples of the inorganic cation M ^{m +} include monovalent inorganic cations M ¹⁺ such as Li ⁺ , Na ⁺ , K ⁺ , and Cs ⁺ ; Mg ²⁺ , Ca ²⁺ , Zn ²⁺ , Pd ²⁺ , Sn ²⁺ , ^{hg 2+, Rh 2+, Cu 2+} , Be 2+, Sr 2+, Ba 2+, 2 divalent inorganic cations M ²⁺ of Pb ²⁺ and the like; and trivalent inorganic cation of Ga ³⁺ etc. M ³⁺ is mentioned. Among these, Li ⁺ , Na ⁺ , Mg ^2+, and Ca ²⁺ are preferable because they have a small ionic radius and can be easily used for power storage devices and the like, and a more preferable inorganic cation M ^{m +} is Li ⁺ .

  The compound (1) according to the present invention includes all compounds composed of combinations of the above cations and anions. Specific examples of the ionic compound (1) include triethylmethylammonium cyanofluorooxalate borate, triethylammonium dicyanooxalatoborate, tributylammonium dicyanooxalatoborate, triethylammonium dicyanomalonatoborate, 1-ethyl-3-methylimidazo Rium dicyanooxalatoborate, triethylmethylammonium dicyanosuccinateborate, triethylmethylammonium dicyanooxalatoborate (triethylmethylammonium dicyanooxalylborate), triethylmethylammonium methylcyanooxalatoborate, triethylmethylammonium trifluoromethylcyanooxalatoborate, 1-ethyl-3-methylimidazolium cyanophenylmer Salts of organic cations such as natoborate; lithium cyanophenyl oxalate borate, sodium dicyano oxalate borate, magnesium bis (dicyano oxalate borate), lithium trifluoromethyl cyanosuccinate borate, lithium cyanophenyl oxalate ethoxyborate, lithium cyanopenta Fluorophenoxyoxalatobutoxyborate, lithium trifluoromethoxycyanomalonatoborate, lithium cyano (pentafluorophenoxy) succinateborate, lithium cyano (acetoxy) oxalatoborate, lithium cyano (trifluoroacetoxy) malonatoborate, lithium cyano ((methoxy Carbonyl) oxo) oxalatoborate, lithium cyano (fluorosulfonate) oxalatoborate Lithium cyano (trifluoromethanesulfonate) oxalatoborate, lithium cyano (methanesulfonate) oxalatoborate, lithium cyano (p-toluenesulfonate) oxalatoborate, lithium cyano (fluorosulfonyl) oxalatoborate, lithium Cyano (acetyl) oxalatoborate, lithium cyano (trifluoroacetyl) oxalatoborate, lithium cyano (trimethylsiloxy) oxalatoborate, lithium dicyanooxalatoborate (lithium dicyanooxalylborate), lithium cyanofluorooxalatoborate (lithium cyano) And salts of inorganic cations such as fluorooxalyl borate).

2-1. Production Method The present invention includes a production method of the compound (1).
The cyanoborate compound represented by the general formula (1) can be produced by reacting a specific boron compound with an alkylsilyl compound or a metal cyanide. In addition, you may use the halogen salt of an organic or inorganic cation for the said reaction as needed.

Preferred boron compounds that can be used in the production method of the present invention are represented by the general formula B (Y ′) _q (X ¹⁵ ) _{3 -q} or M ⁺ B (Y ′) _q (X ¹⁵ ) _{4 -q.} organic halogen compounds (Y ', M ⁺ similarly Y in the general formula (1), and M ^{m +} is an m = 1, X ¹⁵ is a halogen, q represents 2 or 3). Among these, B (Y) _t (X) _1-t (OCO (CH ₂ ) _n COO) or M ⁺ B (Y) _t (X) _2−t (OCO (CH ₂ ) _n COO) (where Y As in the definition in the general formula (1), X is a halogen, and n = 0 to 10, t = 0 or 1) can be suitably used. Specifically, LiB (F) ₂ (OCOCOO), LiB (F) (Me) (OCOCOO), LiB (F) (CF ₃ ) (OCOCOO), LiB (F) (OSO ₂ CF ₃ ) (OCOCOO) _{, LiB (F) 2 (OCOCH} 2 COO), LiB (Cl) (OCH 2 CH = CH 2) (OCOCOO), LiB (OSO 2 F) (F) (OCOCH 2 CH 2 COO), Et 3 NHB (F ) (OCOCF ₃ ) (OCOCOO), Et ₃ MeNB (Ph) (F) (OCOCOO), EMImB (OCOCH ₃ ) (Cl) (OCOCH ₂ COO), Et ₄ NB (OCF ₃ ) (F) (OCOCOO), _{Et 3 MeNB (OCOPh) (F} ) (OCOCOO), LiB (OMe) (F) (OCOCOO), LiB (CH 2 CH = CH 2) , such as (F) (OCOCOO), And androgenic, alkyl group, and an organic group such as an aryl group, or alkanoyl group, organic boron halide compound bonded to the boron and the like. In addition, said organic boron halide compound is, for example, Chemistry-A European Journal 2009, 15, 10, p2270-p2272. It can manufacture with reference to the method as described in (1).

  As a cyan source for introducing a cyano group into the organic boron halide compound, an alkylsilyl compound or a metal cyanide can be used. Specific examples of the alkylsilyl compound include trimethylsilylcyanide, triethylsilylcyanide, triisopropylsilylcyanide, alkyldimethylcyanide such as ethyldimethylsilylcyanide, isopropyldimethylsilyl chloride, tert-butyldimethylsilylcyanide; dimethyl Examples thereof include alkylarylsilyl cyanides such as phenylsilylcyanide and phenyldimethylsilylcyanide. Examples of the metal cyanide include copper cyanide, zinc cyanide, potassium cyanide, sodium cyanide, lithium cyanide and the like. Of these, alkylsilylcyanides or alkylarylsilylcyanides are preferably used. More preferred is trialkylsilyl cyanide. More preferred is trimethylsilylcyanide.

The production method of the present invention may be performed in the presence of a halogen salt of an organic or inorganic cation.
As the halogen constituting the halogen salt of the organic or inorganic cation, F, Cl, Br and I are preferable, and Cl or Br is more preferable. On the other hand, the organic or inorganic cation constituting the halogen salt of an organic or inorganic cation includes the organic or inorganic cation constituting the compound (1) described above.

  Preferred halogen salts of organic or inorganic cations include triethylammonium bromide, tributylammonium bromide, triethylmethylammonium bromide, 1-ethyl-3-methylimidazolium bromide, lithium bromide, triethylammonium chloride, tributylammonium chloride, triethylmethylammonium chloride. 1-ethyl-3-methylimidazolium chloride, triethylmethylammonium chloride, and lithium chloride. More preferred halogen salts of organic or inorganic cations are triethylammonium bromide, triethylmethylammonium bromide, lithium bromide, triethylammonium chloride, triethylmethylammonium chloride, lithium chloride, and more preferably triethylammonium bromide, triethylmethylammonium bromide, Lithium bromide.

  The amount of the halogen salt of the organic or inorganic cation used is preferably 1: 5 to 5: 1 (boron compound: halogen salt of organic or inorganic cation, molar ratio) with respect to the boron compound. More preferably, it is 1: 2 to 2: 1, and still more preferably 1: 0.8 to 1: 1.2. If the blending amount of the organic or inorganic cation halogen salt is too small, removal of by-products may be insufficient, or the target amount may not be efficiently generated due to insufficient cation amount. On the other hand, if the amount of the halogen salt of the organic or inorganic cation is too large, the halogen salt of the organic or inorganic cation tends to remain as an impurity.

  In the production method of the present invention, it is preferable to use a reaction solvent in order to allow the reaction to proceed uniformly. The reaction solvent is not particularly limited as long as it dissolves the above raw materials, and water or an organic solvent is used. Examples of organic solvents include hydrocarbon solvents such as toluene, xylene, benzene and hexane, chlorine solvents such as chloroform, dichloromethane, dichloroethane, chlorobenzene and dichlorobenzene, diethyl ether, cyclohexyl methyl ether, dibutyl ether, dimethoxyethane, and dioxane. , Ether solvents such as tetrahydrofuran and dioxolane, ester solvents such as ethyl acetate and butyl acetate, ketone solvents such as 2-butanone and methyl isobutyl ketone, alcohol solvents such as methanol, ethanol, 2-propanol and butanol, acetonitrile , Nitrile solvents such as isobutyronitrile, valeronitrile, benzonitrile, γ-butyrolactone, ε-caprolactone, ethylene carbonate, propylene carbonate, dimethyl Examples include carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl sulfoxide, dimethylformamide, N-methyl-2-pyrrolidone and the like. These reaction solvents may be used alone or in combination of two or more. Preferred are chlorinated solvents such as chloroform, dichloromethane, dichloroethane, chlorobenzene and dichlorobenzene, and nitrile solvents such as acetonitrile, isobutyronitrile, valeronitrile and benzonitrile. More preferred are nitrile solvents. The reaction conditions are not particularly limited. For example, the reaction temperature may be 20 ° C. to 150 ° C. (more preferably 30 ° C. to 120 ° C., still more preferably 50 ° C. to 100 ° C.), and the reaction time may be 1 hour to 50 hours. (More preferably 2 hours to 10 hours).

2-2. Cation Exchange Reaction The cyanoborate compound obtained by the above production method may further undergo a cation exchange reaction. Since the characteristics of the cyanoborate compound represented by the general formula (1) depend on the cation species, cyanoborate salts having different characteristics can be easily obtained by performing a cation exchange reaction.

  The cation exchange reaction may be performed by reacting the cyanoborate compound represented by the general formula (1) obtained by the above production method with an ionic substance having a desired cation. The ionic substance may be a compound having a desired cation, such as hydroxide, halogen salt, tetrafluoroborate, hexafluorophosphate, perchlorate, bis (trifluoromethanesulfonyl). ) Imide salts and the like. The conditions for the cation exchange reaction are not particularly limited, and the reaction temperature and time may be appropriately adjusted according to the progress of the reaction. Moreover, you may use a solvent as needed, for example, the reaction solvent mentioned above is used preferably.

2-3. Purification In the production method of the present invention, after the above reaction, purification may be performed to further reduce the amount of impurities in the produced compound (1) (crude product) and increase the purity. The purification method is not particularly limited. For example, the product is washed with water, an organic solvent, and a mixed solvent thereof, the oxidizing agent treatment in which the product is brought into contact with an oxidizing agent, the adsorption purification method, the reprecipitation method, the liquid separation. Any conventionally known purification method such as extraction, recrystallization, crystallization, and purification by chromatography can be employed.

  These purification methods may be implemented individually by 1 type, or may combine 2 or more types. In addition, from the viewpoint of reducing the impurities, it is preferable to employ at least one of an oxidant treatment, an adsorption purification method, a liquid separation extraction method, and a crystallization method, and it is particularly preferable to implement all of them.

3. Composition The present invention also includes a composition comprising the cyanoborate compound of the present invention and a medium.
Although it does not specifically limit as said medium, A nonaqueous solvent, a polymer, a polymer gel, etc. are mentioned. As the non-aqueous solvent, a solvent having a large dielectric constant, high solubility of the compound (1), a boiling point of 60 ° C. or higher, and a wide electrochemical stability range is preferable. More preferably, it is an organic solvent (non-aqueous solvent) having a low water content. Examples of such organic solvents include ethylene glycol dimethyl ether (1,2-dimethoxyethane), ethylene glycol diethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 2,6-dimethyltetrahydrofuran, tetrahydropyran, crown ether, triethylene glycol dimethyl ether, Ethers such as tetraethylene glycol dimethyl ether, 1,4-dioxane, 1,3-dioxolane; dimethyl carbonate, ethyl methyl carbonate (methyl ethyl carbonate), diethyl carbonate (diethyl carbonate), diphenyl carbonate, methyl phenyl carbonate, etc. Chain carbonates of ethylene carbonate (ethylene carbonate), propylene carbonate (propylene carbonate), 2,3-dimethylethylene carbonate, butyrate , Cyclic carbonates such as vinylene carbonate and 2-vinylethylene carbonate; aliphatic carboxylic acid esters such as methyl formate, methyl acetate, propionic acid, methyl propionate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate; Aromatic carboxylic acid esters such as methyl acid and ethyl benzoate; carboxylic acid esters such as γ-butyrolactone, γ-valerolactone, and δ-valerolactone; trimethyl phosphate, ethyldimethyl phosphate, diethylmethyl phosphate, phosphorus Phosphate esters such as triethyl acid; Nitriles such as acetonitrile, propionitrile, methoxypropionitrile, glutaronitrile, adiponitrile, 2-methylglutaronitrile, valeronitrile, butyronitrile, isobutylnitrile; N-methylformamide, N-Echi Amides such as formamide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidinone, N-vinylpyrrolidone; dimethylsulfone, ethylmethylsulfone, diethylsulfone, sulfolane, 3-methylsulfolane, 2,4 -Sulfur compounds such as dimethylsulfolane: alcohols such as ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether; sulfoxides such as dimethyl sulfoxide, methyl ethyl sulfoxide, diethyl sulfoxide; benzonitrile, tolunitrile, etc. Aromatic nitriles; nitromethane, 1,3-dimethyl-2-imidazolidinone, 1,3-dimethyl-3,4,5,6-tetrahydro-2 (1H) -pyrimidinone , 3-methyl-2-oxazolidinone and the like. Among these, chain carbonic acid esters, cyclic carbonic acid esters, aliphatic carboxylic acid esters, carboxylic acid esters, and ethers are preferable, and dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, γ- Butyrolactone, γ-valerolactone and the like are more preferable. The said solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

  As a polymer used as a medium, an epoxy compound (polyethylene oxide (PEO), which is a homopolymer or copolymer of ethylene oxide, propylene oxide, butylene oxide, allyl glycidyl ether, etc.) or a polyether polymer such as polypropylene oxide), Methacrylic polymers such as polymethyl methacrylate (PMMA), nitrile polymers such as polyacrylonitrile (PAN), fluoropolymers such as polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene, and copolymers thereof Etc. In addition, a polymer gel obtained by mixing these polymers with another organic solvent can also be used as the medium according to the present invention. Examples of the other organic solvent include the aprotic solvents described above.

  When the polymer gel is used as a medium, a solution in which the compound (1) is dissolved in the above-mentioned aprotic solvent is added dropwise to a polymer formed by a conventionally known method, so that the compound (1) and aprotic A method of impregnating and supporting a solvent; a method in which a polymer and the compound (1) are melted and mixed at a temperature equal to or higher than the melting point of the polymer, and then formed into a film and impregnated with an aprotic organic solvent; (1) A method in which a solution and a polymer are mixed and then formed into a film by a casting method or a coating method, and the organic solvent is volatilized (the gel electrolyte); the polymer and the compound (at a temperature equal to or higher than the melting point of the polymer). 1) and a method of melting and mixing (intrinsic polymer electrolyte); and the like.

  The composition of the present invention may contain only the cyanoborate compound (1) and the medium according to the present invention, but may contain an electrolyte other than the cyanoborate compound (1). By using another electrolyte, the absolute amount of ions in the composition can be increased, and when the composition is used as an electrolyte or an electrolytic solution material, the electrical conductivity can be improved.

As other electrolytes, those having a large dissociation constant in the composition and having an anion that is difficult to solvate with the non-aqueous solvent are preferable. Examples of the cation species constituting other electrolytes include alkali metal ions such as Li ⁺ , Na ⁺ and K ⁺ , alkaline earth metal ions such as Ca ²⁺ and Mg ²⁺ , and the above-described onium cation. In particular, chain quaternary ammonium or lithium ions are preferred. On the other hand, as anion species, PF ₆ ⁻ , BF ₄ ⁻ , Cl ⁻ , Br ⁻ , ClO ₄ ⁻ , AlCl ₄ ⁻ , C [(CN) ₃ ] ⁻ , N [(CN) ₂ ] ⁻ , N [( SO ₂ CF ₃ ) ₂ ] ⁻ , N [(SO ₂ F) ₂ ] ⁻ , CF ₃ (SO ₃ ) ⁻ , C [(CF ₃ SO ₂ ) ₃ ] ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ and dicyanotri An azolate ion (DCTA) etc. are mentioned. Among these, PF ₆ ⁻ and BF ₄ ⁻ are more preferable. Specifically, triethylmethylammonium as cationic component, an anionic component as BF ₄ ^- triethylmethylammonium tetrafluoroborate containing, tetraethylammonium as a cationic component, BF ₄ as an anion component ^- tetraethylammonium tetrafluoroborate containing, triethyl as a cationic component hexafluorophosphate triethylmethylammonium containing lithium as a cation component, PF ₆ as an anion component ^{- -} methylammonium, PF ₆ as an anion component lithium hexafluorophosphate or the like including a can be mentioned as preferable other electrolytes.

Specific examples of other electrolytes include alkali metal salts and alkaline earth metal salts of trifluoromethanesulfonic acid such as LiCF ₃ SO ₃ , NaCF ₃ SO ₃ , KCF ₃ SO ₃ ; LiC (CF ₃ SO ₂ ) ₃ , Alkali metal salts and alkaline earth metal salts of perfluoroalkanesulfonic imides such as LiN (CF ₃ CF ₂ SO ₂ ) ₂ and LiN (FSO ₂ ) ₂ ; hexafluorophosphoric acids such as LiPF ₆ , NaPF ₆ and KPF ₆ alkali metal salts and alkaline earth metal salts of; tetrafluoroborate salt LiBF _4, NaBF _4, etc.; perchlorate alkali metal salts and alkaline earth metal salts of _4, NaClO _4, etc. LiClO LiAsF _6, LiI, LiSbF ₆ Alkali metal salts such as LiAlO ₄ , LiAlCl ₄ , LiCl, NaI, NaAsF ₆ and KI; tetraethylammonium perchlorate Quaternary ammonium salts of perchloric acid such as: (C ₂ H ₅ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₃ (CH ₃ ) quaternary ammonium salts of tetrafluoroboric acid such as NBF ₄ , (C ₂ Quaternary ammonium salts such as H ₅ ) ₄ NPF ₆ ; quaternary phosphonium salts such as (CH ₃ ) ₄ P · BF ₄ and (C ₂ H ₅ ) ₄ P · BF ₄ are suitable as other electrolytes. is there. Among these, alkali metal salts and / or alkaline earth metal salts are preferable. Further, from the viewpoint of solubility in an aprotic organic solvent and ion conductivity, LiPF ₆ , LiBF ₄ , LiAsF ₆ , alkali metal salt or alkaline earth metal salt of perfluoroalkanesulfonic acid imide, A quaternary ammonium salt is preferable, and a chain quaternary ammonium salt is preferable from the viewpoint of reduction resistance. As the alkali metal salt, a lithium salt, a sodium salt, and a potassium salt are preferable, and as the alkaline earth metal salt, a calcium salt and a magnesium salt are preferable. More preferred is a lithium salt.

  In addition, when using other electrolyte together, it is preferable that the usage-amount is 0.1 mass part or more with respect to 100 mass parts of said cyanoborate compounds (1), More preferably, it is 1 mass part or more, Furthermore, Preferably it is 10 mass parts or more, Preferably it is 100 mass parts or less, More preferably, it is 50 mass parts or less, More preferably, it is 30 mass parts or less.

4). Use The cyanoborate compound of the present invention and the composition of the present invention containing the compound are suitably used as an electrolyte or an electrolyte solution material for various power storage devices. As an electricity storage device provided with the electrolytic solution of the present invention, in addition to batteries having charging and discharging mechanisms such as primary batteries, lithium (ion) secondary batteries, fuel cells, molten salt batteries, electrolytic capacitors, electric double layer capacitors, It can be suitably used as an electrolyte for lithium ion capacitors, solar cells and the like. As the electrolyte or electrolyte solution material, it can be used as the main electrolyte or sub-electrolyte of the electrolyte solution of the above various electric storage devices, and further as an additive of the electrolyte solution.

The compound (1) according to the present invention is expected to become an ionic liquid that takes a liquid state at 100 ° C. or lower by selecting the cation M ^{m +} . In general, an ionic liquid has a high electrochemical and thermal stability because it is a liquid having an ionic bond, and further has a property of selectively absorbing a specific gas such as carbon dioxide. It is known that the compound (1) according to the present invention also has the same characteristics as these. Therefore, the cyanoborate compound (1) of the present invention can be used repeatedly as an organic synthesis reaction solvent that utilizes high thermal stability, in addition to the above-described electrochemical material applications such as various power storage devices. Use as a sealant and lubricant for moving parts of machines, use as a cationic dye for color filters for optical filters such as color filters, cationic polymerization initiators for paints, adhesives and coatings, and chemical amplification Use as an acid generator that can be used as an acid generator for mold resists, antistatic agents, electrolytes for chemical sensors, conductivity to resins, paints, glass, etc. using both electrochemical properties and thermal stability Use as a property-imparting agent and use as a gas absorbent such as carbon dioxide are expected because of its ability to absorb gas.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.

[NMR measurement]
Using “Unity Plus” (400 MHz) manufactured by Varian, ¹ H-NMR, ¹³ C-NMR, and ¹⁹ F-NMR spectra were measured, and the structure of the sample was analyzed based on the peak intensities of proton, carbon, and fluorine. . ^For the measurement of ¹¹ B-NMR spectrum, “Advanced 400M” (400 MHz) manufactured by Bruker was used.

In addition, the measurement of a NMR spectrum measured the measurement sample which dissolved the reaction solution or the obtained salt so that the density | concentration might be 1 mass%-5 mass% in heavy dimethyl sulfoxide, and does not contain a boron element, but is made from aluminum oxide. Were measured at room temperature (25 ° C.) and 64 times of integration. In the measurement of ¹ H-NMR and ¹³ C-NMR spectrum, tetramethylsilane is used as a standard substance, in the measurement of ¹⁹ F-NMR spectrum, trichlorofluoromethane is used as a standard substance, and in the measurement of ¹¹ B-NMR spectrum, 1-ethyl-3-methylimidazolium tetrafluoroborane was quantified as a standard substance for calibration.

Experimental Example 1 A synthetic structural formula of lithium cyano (fluoro) oxalatoborate (LiB (CN) (F) (OC (O) C (O) O)) is shown in the following formula.

  To a 100 mL three-necked flask equipped with a stirrer, 2.19 g (15.2 mmol of lithium difluorooxalatoborate) (15.2 mmol, lithium difluorooxalatoborate was added to Chemistry-A European Journal, 2009, 15). , 10, p2270-p2272.), And the inside of the flask was replaced with nitrogen gas. To this, 20 mL of isobutyronitrile was added, and while stirring the resulting mixed solution, 4.7 mL (37.9 mmol, 2.5 equivalents relative to the boron compound) of trimethylsilylcyanide was added dropwise at room temperature. After that, the reaction solution was heated to 80 ° C. with an oil bath, and stirring was continued at this temperature for 2.5 hours to carry out the reaction.

Thereafter, the organic solvent was distilled off under reduced pressure from the obtained yellow solution and concentrated to obtain a pale yellow solid (lithium cyano (fluoro) oxalatoborate). (Yield: 0.55 g (3.65 mmol), yield: 73%).
¹⁹ F-NMR (d6-DMSO) δ-140.79 (q, J = 30.8 Hz)
¹¹ B-NMR (d6-DMSO) δ-0.37 (d, J = 30.8 Hz)

Experimental Example 2 Synthesis of lithium dicyanooxalatoborate (LiB (CN) ₂ (OC (O) C (O) O)) The structural formula is shown below.

  To a 100 mL three-necked flask equipped with a stirrer, 0.72 g (5.0 mmol) of lithium difluorooxalatoborate (lithium difluorooxalylborate) was added, and the inside of the flask was replaced with nitrogen gas. To this, 5 mL of benzonitrile was added. While stirring the obtained mixed solution, 1.6 mL (12.9 mmol, 2.4 equivalents relative to the boron compound) of trimethylsilylcyanide was added dropwise at room temperature (25 ° C.). Thereafter, the reaction solution was heated to 80 ° C. with an oil bath, and stirred at the same temperature for 47 hours to be reacted.

Thereafter, the organic solvent was distilled off under reduced pressure from the obtained yellow solution and concentrated to obtain a pale yellow solid (lithium dicyanooxalatoborate). (Yield: 0.40 g (2.53 mmol), yield: 51%).
¹¹ B-NMR (d6-DMSO) δ-6.9 (s)

Experimental Example 3 LSV Measurement Lithium cyano (fluoro) oxalatoborate synthesized in Experimental Example 1, lithium dicyanooxalatoborate synthesized in Experimental Example 2, and lithium difluorooxalatoborate resistance by linear sweep voltammetry (LSV) measurement The voltage range was measured. As the measurement solution, the salt obtained in Experimental Examples 1 and 2 was dissolved in dehydrated ethylene carbonate / ethyl methyl carbonate (1: 1 v / v%) (manufactured by Kishida Chemical Co., Ltd.), and the concentration was 1.0 M (= mol / L). ) Was used. The measurement conditions are shown below, and the results are shown in FIGS.

[LSV measurement]
The withstand voltage range was measured using a standard voltammetric tool HZ-3000 (trade name, manufactured by Hokuto Denko) using a three-pole cell in a dry room set at 20 ° C. The measurement conditions are as follows.
Working electrode: Glassy carbon electrode (electrode area: 7.85 × 10 ⁻³ cm ² )
Reference electrode: Ag electrode, counter electrode: platinum electrode Solution concentration: 1.0 M (= mol / L)
Solvent: ethylene carbonate / ethyl methyl carbonate (1: 1 v / v%)
Sweep speed: 100 mV / s
Sweep range: Natural potential to + 10V
Reference current value: 0.1 mA

From the results shown in FIG. 1, no current (0.1 mA or more, converted to 12.7 mA / cm ² or more from the above measurement conditions) up to 10 V (silver electrode reference) was observed, and the lithium dicyanooxax of the present invention was not observed. It is considered that an electrolytic solution containing latoborate as an electrolyte hardly causes decomposition of the electrolytic solution even when used in a high voltage range.

  Further, from the results shown in FIG. 2 and FIG. 3, the voltage resistance is improved by introducing a cyano group into the borate compound, and the electrolytic solution using lithium cyano (fluoro) oxalatoborate as an electrolyte is lithium. It is considered that the electrolytic solution is hardly decomposed even when used in a higher voltage range than the electrolytic solution using difluorooxalatoborate as an electrolyte.

Experimental Example 4 Battery Characteristic Evaluation <Preparation of Nonaqueous Electrolyte>
Lithium hexafluorophosphate as an electrolyte (LiPF ₆ , manufactured by Kishida Chemical Co., Ltd., LBG grade), lithium cyano (fluoro) oxalatoborate (LiBFCN (C ₂ O ₄ )) obtained in Experimental Examples 1 and 2 above, Lithium dicyanooxalatoborate (LiB (CN) ₂ (C ₂ O ₄ )) is added to a mixed solvent of ethylene carbonate (EC) / ethyl methyl carbonate (EMC) which is a non-aqueous solvent so as to have the composition shown in Table 1. (EC: EMC = 3: 7 (volume ratio), all were manufactured by Kishida Chemical Co., Ltd., LBG grade) to prepare non-aqueous electrolytes A to E.

<Production of coin-type lithium battery>
Commercially available ternary positive electrode sheet (positive electrode current collector; aluminum foil, positive electrode active material: LNMC, initial charge capacity: 2.0 mAh / cm ² ) and commercially available negative electrode sheet (negative electrode current collector; copper foil, negative electrode active material) : Artificial graphite, initial charge capacity: 2.4 mAh / cm ² ) was punched into a circle. A polyethylene separator was also punched out into a circle. The above-mentioned positive electrode, negative electrode sheet, separator and CR 2032 coin type battery parts purchased from Hosen Co., Ltd. (positive electrode case (SUS316L, aluminum clad treated product), negative electrode sealing plate (SUS316L), spacer (1 mm thickness, SUS316L) , A wave washer (made of SUS316L), a gasket (made of polypropylene)), a gasket-attached negative electrode sealing plate, a wave washer, a spacer, a negative electrode current collector, and a separator were stacked in this order. E was impregnated on each separator. Next, the positive electrode was placed so that the positive electrode active material layer formation surface was opposed to the negative electrode active material layer formation surface, and a positive electrode case was further stacked thereon, and caulking was performed to produce a coin-type lithium battery.

<High temperature storage test>
About each coin type lithium battery using non-aqueous electrolytes A to E, using a charge / discharge test apparatus (“ACD-01”, manufactured by Asuka Electronics Co., Ltd.), under a temperature condition of 25 ° C., a charge rate of 0.5 C In (constant current constant voltage mode), the battery was charged to 4.4 V, and then discharged to 3.0 V at a discharge rate of 0.5 C (constant current mode). The discharge capacity at this time is defined as the initial discharge capacity (A). Next, each coin-type lithium battery was again charged to 4.4 V under a temperature condition of 25 ° C. at a charging rate of 0.5 C (constant current constant voltage mode), and then stored at 60 ° C. for one week. Thereafter, the battery is discharged at a discharge rate of 0.5 C (constant current mode) to a 3.0 V cut, charged at a charge rate of 0.5 C (constant current and constant voltage mode), and then discharged at a discharge rate of 0.5 C (constant current). In mode), discharging was performed up to 3.0V cut. The discharge capacity at this time is the recovery capacity (B) after high-temperature storage. The capacity recovery rate (storage characteristics) after high-temperature storage was calculated from the following formula. The results are shown in Table 2.
Capacity recovery rate (%) = (recovery capacity after high temperature storage (B) / initial discharge capacity (A)) × 100

A coin-type lithium battery of the present invention employing non-aqueous electrolytes B to E containing (LiBFCN (C ₂ O ₄ )) and (LiB (CN) ₂ (C ₂ O ₄ )) as electrolytes shown in Table 2, From the comparison with a coin-type lithium battery that employs a non-aqueous electrolyte A containing only LiPF ₆ as an electrolyte, by using the cyanoborate compound, an increase in impedance can be suppressed even after high-temperature storage, and the capacity recovery rate can be reduced. It can be seen that it can be improved.

Claims (3)

A cyanoborate compound represented by the general formula (1).

(In formula (1), M ^{m +} represents a proton, monovalent, divalent, or trivalent organic or inorganic cation, Y represents a halogen or a cyano group , m represents an integer of 1 to 3, and n represents Represents 0. ) A composition comprising the compound of claim 1 and a medium. An electrolyte comprising the compound according to claim 1 .