JP5798509B2 - Electrolyte material and method for producing the same - Google Patents

Description

  The present invention relates to an electrolyte material and a manufacturing method thereof.

  Electrolyte materials including ionic compounds are used in ion conductors such as various types of batteries by ion conduction, in addition to batteries having charge / discharge mechanisms such as primary batteries, lithium ion secondary batteries and fuel cells, electric field capacitors. It is used in electrochemical devices such as 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 Patent Documents 1 and 2, among the above ionic compounds, an ionic compound having an anion having a structure in which N, C, B, or the like is a central element and a cyano group is bonded thereto is studied. However, it has been shown to be suitably used as an electrolyte for various electrochemical devices since it has excellent ion conductivity and exhibits properties such as thermal, physical, and electrochemical stability.

In particular, regarding ionic compounds having cyanoborate whose central element is boron as an anion, for example, Patent Documents 3 and 4 disclose tetracyanoborate ([B ⁻ (CN) ₄ ], hereinafter sometimes referred to as TCB). An ionic compound in which is an anion is described. Patent Document 5 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 2004-165131 A JP 2004-6240 A JP-T-2006-517546 International Publication No. 2010/021391 Pamphlet International Publication No. 2010/086131 Pamphlet

  Among the above ionic compounds, cyanoborate salts having anions having a structure in which a cyano group and another organic group are bonded to boron are excellent in ionic conductivity and are known to be suitably used as electrolytes for various power storage devices. Yes.

  However, the present inventors have clarified that the above cyanoborate salt has a very high affinity with water and it is difficult to reduce the amount of water even when heated to a high temperature. As described above, when the cyanoborate salt in which moisture remains is used in the electrolytic solution provided in the above-described power storage device, the voltage resistance of the electrolytic solution is reduced, or the electrode provided in the power storage device or other As a result, the surrounding materials are corroded, and as a result, there is a problem that the performance such as the cycle characteristics of the electricity storage device is deteriorated.

  The present invention has been made paying attention to the above-described circumstances, and an object thereof is to provide an electrolyte material having a reduced water content that adversely affects the electrochemical characteristics of the electricity storage device and a method for producing the same. There is.

The electrolyte material according to the present invention is
(I) an ionic compound represented by the following general formula (1) and a medium, wherein the concentration of the ionic compound is 1% by mass or more and the water content is 50 ppm or less, or
(Ii) an ionic compound represented by the following general formula (1), and the water content is 500 ppm or less,
However, it has characteristics.
_{^{Kt 1 m + [B - (}} CN) 4-n Y n] m (1)
(Wherein Kt ₁ represents an inorganic cation, m is an integer of 1 to 3, n is 0, Y is halogen or (X ² R), X ² is O or S, and R is H or a hydrocarbon group having 1 to 10 carbon atoms is represented.)
When the electrolyte material having a low water content is used in various power storage devices, the withstand voltage characteristics of the electrolytic solution are not easily deteriorated, and the members of the power storage device such as electrodes are not easily generated. Therefore, it is considered that the performance of the electricity storage device is hardly lowered.

The electrolyte material (ii) preferably further contains a medium. In the above (i) and (ii), the medium is preferably an aprotic solvent. Further, the electrolyte material has a 3.8 V to 13.8 V (vs. Li / Li ⁺ ) region when a linear sweep voltammetry measurement is performed under the following conditions using a tripolar electrochemical cell. The observed peak current value is preferably ² mA / cm ² or less.
Measurement conditions Working electrode: Glassy carbon electrode Reference electrode: Ag electrode Counter electrode: Pt electrode Solution concentration based on ionic compound contained in electrolyte material: 7% by mass
Solvent: Solvent for electricity storage device Sweeping range: Natural potential to 10V
Sweep speed: 100 mV / sec

  The production method of the present invention is a production method of the above electrolyte material, and after mixing the ionic compound represented by the general formula (1) with a lactone solvent and / or a carbonate solvent, (i) distillation And / or (ii) contacting with the molecular sieve.

In the present invention, the ionic compound represented by the general formula (1) is mixed solvent A in which the mixing ratio of the organic solvent for phase separation with water and water is 20: 1 to 2: 1 by mass ratio. An electrolyte having an extraction step, and an extraction step (extraction step (iii)) in which the mixing ratio of the organic solvent that is phase-separated from water and water is 1: 2 to 1:20 by mass ratio. Also included are a method for producing a material, and a method for producing an electrolyte material represented by the following general formula (2), in which an electrolyte material obtained by the production method is reacted with a salt of an onium cation.
_{^{Kt 2 m + [B - (}} CN) 4-n Y n] m (2)
(Wherein Kt ₂ represents an onium cation, m is an integer of 1 to 3, n is 0, Y is halogen or (X ² R), X ² is O or S, and R is H or a hydrocarbon group having 1 to 10 carbon atoms is represented.)

  An electricity storage device using the above electrolyte material is a preferred embodiment of the present invention.

  According to the present invention, an electrolyte material having a reduced water content that adversely affects the electrochemical characteristics of an electricity storage device can be obtained. Therefore, by using the electrolyte material of the present invention as an electrolytic solution, an electrolytic solution having good withstand voltage characteristics can be obtained. In addition, it is considered that this electrolytic solution is unlikely to cause corrosion deterioration of an electricity storage device member such as an electrode, and as a result, deterioration of electrochemical characteristics of the electricity storage device can also be suppressed.

FIG. 1 is a diagram showing the LSV measurement results of Experimental Example 1. FIG. 2 is a diagram showing the LSV measurement result of Experimental Example 7-1. FIG. 3 is a diagram showing the LSV measurement result of Experimental Example 7-2. FIG. 4 is a diagram showing the LSV measurement result of Experimental Example 7-3. FIG. 5 is a diagram showing the LSV measurement results of Experimental Example 7-4.

The electrolyte material according to the present invention includes (i) an ionic compound represented by the following general formula (1) (hereinafter sometimes referred to as ionic compound (1)) and a medium, and the concentration of the ionic compound. Is 1 mass% or more and the water content is 50 ppm or less (electrolyte material (i)), or (ii) contains an ionic compound represented by the following general formula (1), and The water content is 500 ppm or less (electrolyte material (ii)).
_{^{Kt 1 m + [B - (}} CN) 4-n Y n] m (1)
(Wherein Kt ₁ represents an inorganic cation, m represents an integer of 1 to 3, n represents an integer of 0 to 3, Y is a halogen or (X ² R), and X ² is O or S. And R represents H or a hydrocarbon group having 1 to 10 carbon atoms.)

  First, the electrolyte material (i) of the present invention will be described.

≪Electrolyte material (i) ≫
The electrolyte material (i) of the present invention includes an ionic compound represented by the general formula (1) and a medium, and the concentration of the ionic compound in the electrolyte material (i) is 1% by mass or more. And it has the characteristics in content of water being 50 ppm or less.

  The inventors of the present invention have repeatedly studied the characteristics of the ionic compound represented by the general formula (1). As a result, the amount of water contained in the electrolyte material (i) depends on the resistance of the electrolytic solution and also the electricity storage device. As a result of further investigations in order to provide an ionic compound that has been found to have an influence on the deterioration of electrochemical characteristics such as voltage characteristics and cycle characteristics and to prevent such characteristic deterioration, it is represented by the general formula (1). If the water content of the electrolyte material (i) containing the ionic compound and the medium so that the concentration of the ionic compound is 1% by mass or more is 50 ppm or less (mass basis, the same applies hereinafter), The present inventors completed the present invention by discovering that deterioration of characteristics, and consequently, deterioration of constituent members and electrochemical characteristics of various power storage devices using this ionic compound hardly occur.

  The water contained in the electrolyte material is, for example, water mixed in the electrolyte material production process due to moisture absorption from the environment such as water or solvent used in the synthesis reaction of the ionic compound (1) or purification, or air. It is thought that it remained. Applications of the electrolyte material of the present invention include electrolytes for the above various power storage devices. If the electrolyte material contains moisture, the withstand voltage characteristics of the electrolyte may be reduced, or moisture may be generated during operation of the power storage device. Electrolysis results in the formation of hydrogen ions, which lowers the pH of the electrolyte (acidic). As a result, the electrode material dissolves, reacts with the electrode material, and corrodes due to the acidic components generated in the electrolyte. There arises a problem that the performance of the electricity storage device deteriorates. Further, when water is electrolyzed, gas is generated, which may increase the internal pressure of various power storage devices having a sealed structure, leading to deformation or breakage. As a result, the device becomes unusable and may cause a safety problem.

  Accordingly, the lower the water content, the better. The water content contained in the electrolyte material (i) is preferably 30 ppm or less, more preferably 20 ppm or less, still more preferably 15 ppm or less, and particularly preferably 10 ppm. It is as follows. The lower limit of the moisture content is not particularly limited and is most preferably 0 ppm, but it is technically difficult to reduce it to 0 ppm, which may not be preferable for economic reasons. Therefore, the lower limit of the water content of the electrolyte material (i) of the present invention may be about 0.1 ppm. This is because if the water content is about 0.1 ppm, the influence on the characteristics of the electrolyte material (i) is small. The lower limit may be about 1 ppm. This is because a remarkable deterioration in characteristics is hardly seen and practical problems are unlikely to occur.

  The water content in the present invention is, for example, described in the examples described later using a Karl Fischer moisture measuring device (for example, a Karl Fischer moisture meter manufactured by Hiranuma Sangyo Co., Ltd.) by coulometric titration or volumetric titration. It is a value measured by the procedure.

  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 ionic compound (1), a boiling point of 60 ° C. or higher, and a wide electrochemical stability range is preferable. More preferably, an aprotic organic solvent having a low water content is used. 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 Chain carbonates such as 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 more 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.

  As a method for producing the electrolyte material (i) when the polymer gel is used as a medium, a solution in which the ionic compound (1) is dissolved in the above-mentioned aprotic solvent in a polymer formed by a conventionally known method is used. A method of dripping and impregnating and supporting the ionic compound (1) and the aprotic solvent; the polymer and the ionic compound (1) are melted and mixed at a temperature equal to or higher than the melting point of the polymer, and a film is formed. A method of impregnating an organic solvent with an aprotic organic solvent; an ionic compound (1) solution previously dissolved in an organic solvent and a polymer are mixed, and then a film is formed by a casting method or a coating method to volatilize the organic solvent. A method (gel electrolyte); a method in which a polymer and an ionic compound (1) are melted at a temperature equal to or higher than the melting point of the polymer, mixed and molded (intrinsic polymer electrolyte);

  The amount of the medium is such that the concentration of the ionic compound (1) in the electrolyte material (i) according to the present invention is 1% by mass or more. In addition, it is preferable that the upper limit of the amount of the medium is such that the concentration of the ionic compound (1) in the electrolyte material (i) is equal to or lower than the saturation concentration. For example, the saturation concentration of lithium tetracyanoborate with respect to γ-butyrolactone is 8.1% by mass, and the saturation concentration of lithium tricyanomethoxyborate is 20.2% by mass. More preferably, in the case of an ionic compound in which n is 0 in the general formula (1), the concentration of the ionic compound (1) in the electrolyte material (i) is more preferably 2% by mass or more, and still more preferably. Is 5% by mass or more, and more preferably 6% by mass or more. The concentration of the ionic compound (1) in the electrolyte material (i) is more preferably 10% by mass or less. On the other hand, in the case of an ionic compound in which n is 1 to 3 in the general formula (1), the concentration of the ionic compound (1) in the electrolyte material (i) is preferably 5% by mass or more, more preferably It is 6 mass% or more, It is more preferable that it is 30 mass% or less, More preferably, it is 25 mass% or less.

≪Electrolyte material (ii) ≫
The present invention also includes an electrolyte material (ii) containing the ionic compound represented by the general formula (1) and having a water content of 500 ppm or less.

  Similarly to the electrolyte material (i), when the electrolyte material (ii) contains moisture, the electric withstand characteristics of the electrolytic solution are deteriorated, and as a result, the cause of the failure of the electrochemical device provided with the electrolyte material (ii) Become. Accordingly, the lower the moisture content, the better. The moisture content contained in the electrolyte material (ii) of the present invention is preferably 300 ppm or less, more preferably 200 ppm, still more preferably 150 ppm or less, particularly preferably 100 ppm. It is as follows. The lower limit of the moisture content is not particularly limited, and is most preferably 0 ppm. However, it is technically difficult to reduce it to 0 ppm, and it may not be preferable for economic reasons. Therefore, in the present invention, the lower limit of the water content may be about 0.1 ppm. This is because if the water content is about 0.1 ppm, the influence on the characteristics of the ionic compound contained in the electrolyte material (ii) is small. The lower limit may be about 1 ppm. This is because a remarkable deterioration in characteristics is hardly seen and practical problems are unlikely to occur.

  Here, the electrolyte material (ii) of the present invention only needs to contain the ionic compound (1). Therefore, in the present invention, it is desirable that the water content contained in the ionic compound (1) (solid form) is in the above range.

  Similarly to the electrolyte material (i), the water content in the electrolyte material (ii) can also be measured by the method described in Examples described later.

  In addition, the method of setting the water content of the electrolyte material in the above range is not particularly limited, but includes, for example, the ionic compound (1) having a reduced water content by adopting the production method of the present invention described later. Electrolyte materials (i) and (ii) can be obtained.

In the electrolyte material (i), (ii) of the present invention, the electrolyte material (i) or (i) is added to the solvent (medium) for the electricity storage device so that the concentration of the ionic compound (1) is in the range of 5 mass% to the saturated concentration. The electrolytic solution prepared by dissolving ii) uses a tripolar electrochemical cell in which the working electrode is a glassy carbon electrode, the reference electrode is an Ag electrode, and the counter electrode is a Pt electrode. When the linear sweep voltammetry measurement is performed at a sweep rate of 100 mV / sec, the peak current value observed in the 3.8 V to 13.8 V (vs. Li / Li ⁺ ) region is ² mA / cm ² or less. Preferably there is.

  Here, the “solvent for an electricity storage device” is a solvent selected from a lactone solvent and a carbonate solvent, and these may be used singly or may be a mixture of two or more solvents. Examples include, but are not limited to, one or more solvents or mixed solvents selected from the group consisting of γ-butyrolactone, propylene carbonate, ethylene carbonate, and ethyl methyl carbonate.

  The electrolytic solution used for the LSV measurement is obtained by dispersing and dissolving the electrolyte material (i) or (ii) in a solvent for an electricity storage device, or a lactone solvent and / or a carbonate solvent as a solvent by a production method described later. Using the solvent used as the solvent for the electricity storage device from the solvent, the ionicity obtained by carrying out the step (i) and / or the step (ii) so that the concentration of the ionic compound (1) is 7% by mass A compound (1) solution (electrolyte material (i)) is mentioned. In the present invention, it is preferable that the peak current value observed when LSV measurement is performed for these electrolytes is in the above range.

As described above, since the electrolyte materials (i) and (ii) of the present invention have a reduced water content, the electrolytic solution caused by water is hardly decomposed, and a high potential side of 13.8 V on the basis of lithium. Even when the potential is scanned up to 1, the observed peak current value (resolved current value) can be kept low. Therefore, it can be seen that the electrolyte materials (i) and (ii) of the present invention can be used as an electrolyte solution material or an electrolyte solution having excellent withstand voltage characteristics. Incidentally, this means that the peak current value is excellent in low enough withstand voltage characteristic, the peak current value is more preferably at 1.5 mA / cm ² or less, more preferably at 1.3 mA / cm ² or less . Particularly preferably, it is 1.0 mA / cm ² or less.

  In addition, when LSV measurement is performed on an electrolytic solution prepared by dissolving the electrolyte materials (i) and (ii) in a solvent, it is preferable that moisture derived from the solvent does not affect the measured value. Specifically, the solvent used for the LSV measurement may be a dehydrated grade solvent having a water content of 30 ppm or less.

<Ionic compound (1)>
Next, the ionic compound of the present invention represented by the general formula (1) will be described. The ionic compound (1) according to the present invention is represented by an inorganic cation represented by Kt ₁ ^{m +} and [B (CN) _4−n Y _n ] ⁻ as represented by the general formula (1). It is an ionic compound composed of a cyanoborate anion.

Cyanoborate anion: [B (CN) _4-n Y _n ] ⁻
Cyano anions according to the present invention, the boron, a cyano group: and -CN, -Y are bonded to the general formula: [B (CN) 4- n Y n] - has a structure represented by. In the above general formula, since n is an integer of 0 to 3, the cyanoborate anion according to the present invention includes a tetracyanoborate anion in which n is 0: [B (CN) ₄ ] ⁻ ; A tricyanoborate anion: [B (CN) ₃ Y] ⁻ ; a dicyanoborate anion in which n is 2: [B (CN) ₂ Y ₂ ] ⁻ ; a monocyanoborate anion in which n is 3: [B ( CN) Y ₃ ] ^- ; cyanoborate anions. As the cyanoborate anion, in the above general formula, n is preferably 0 or 1.

In the anion represented by the above general formula, Y is halogen or (X ² R), and examples of the halogen include F, Cl, Br and I. X ² represents O or S. X ² is preferably O. R represents H or a hydrocarbon group having 1 to 10 carbon atoms. Note that the hydrocarbon group may have a substituent, and in this case, the number of carbons constituting the substituent is not included in the above-described number of carbons. In addition, the hydrocarbon group may contain a hetero atom (O, N, Si, etc.) in a part thereof, and further, a part or all of the hydrogen atoms of the hydrocarbon group may be F, Cl, Br and It may be substituted with a halogen atom such as I. As the hydrocarbon group, a linear, branched or cyclic saturated and / or unsaturated hydrocarbon group having 1 to 10 carbon atoms is preferable, and a more preferable hydrocarbon group is an alkyl group having 1 to 10 carbon atoms, Examples thereof include an alkylsilyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an aryl group, and a benzyl group. Specific examples of the hydrocarbon group R include straight groups such as methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, tert-butyl group, sec-butyl group, pentyl group, hexyl group and octyl group. Chain or branched alkyl groups; cycloalkyl groups such as cyclohexyl groups and cyclopentyl groups; alkenyl groups such as vinyl groups; aryl groups such as phenyl groups, methylphenyl groups, methoxyphenyl groups, dimethylphenyl groups, naphthyl groups; Is mentioned. Preferred are methyl group, ethyl group, propyl group, isopropyl group, butyl group and phenyl group.

Specific cyanoborate anions include tetracyanoborate anions represented by [B (CN) ₄ ] ⁻ ; [B (CN) ₃ (OMe)] ⁻ , [B (CN) ₃ (OEt)] ⁻ , [B (CN) ₃ (Oi-Pr)] ⁻ (“-i-” indicates “iso”, the same applies hereinafter), [B (CN) ₃ (OBu)] ⁻ , [B ( CN) ₃ (OPh)] ⁻ etc .; alkoxytricyanoborate anions such as [B (CN) ₃ (SMe)] ⁻ etc .; thioalkoxytricyanoborate anions such as [B (CN) ₂ (OMe) ₂ ] ⁻ , [ _{B (CN) 2 (OEt)} 2] -, [B (CN) 2 (O-i-Pr) 2] -, [B (CN) 2 (OBu) 2] -, [B (CN) 2 (OPh ) _2] ^-, etc. dialkoxy dicyano borate anion; [B (CN) (OMe ) 3] -, [B (CN) ( ^{_{Et) 3] -, [B}} (CN) (O-i-Pr) 3] -, [B (CN) (OBu) 3] -, [B (CN) (OPh) 3] - or the like of the trialkoxy cyano Borate anion.

Inorganic cation: Kt ₁ ^{m +}
As the inorganic cation Kt ₁ ^{m +} constituting the ionic compound (1) according to the present invention, monovalent inorganic cation Kt ₁ ¹⁺ such as Li ⁺ , Na ⁺ , K ⁺ , Cs ⁺ , Pb ^+, etc .; Mg ^{2+ , Ca 2+, Zn 2+, Pd} 2+, Sn 2+, Hg 2+, Rh 2+, Cu 2+, Be 2+, Sr 2+, 2 divalent inorganic cations of Ba ^2+, etc. Kt ₁ ^{2 +} ; And trivalent inorganic cations Kt ₁ ³⁺ such as Ga ³⁺ . Among these, Li ⁺ , Na ⁺ , Mg ²⁺ and Ca ²⁺ are preferable because they have a small ionic radius and can be easily used as an electricity storage device, and a more preferable inorganic cation is Li ⁺ .

Ionic compound ^{_{(1): Kt 1 m +}} [B - (CN) 4-n Y n] m
The ionic compound (1) according to the present invention includes all compounds composed of a combination of the inorganic cation and the cyanoborate anion. Specific examples of the ionic compound (1) include lithium tetracyanoborate, lithium tricyanomethoxyborate, lithium tricyanoethoxyborate, sodium tetracyanoborate, sodium tricyanomethoxyborate, magnesium bis (tricyanomethoxyborate), lithium Tricyanoisopropoxyborate, lithium tricyanobutoxyborate, lithium tricyanophenoxyborate, lithium tricyano (pentafluorophenoxy) borate, lithium tricyano (trimethylsiloxy) borate, lithium tricyano (hexafluoroisopropoxy) borate, lithium tricia Nomethylthioborate, lithium dicyanodimethoxyborate, lithium cyanotrimethoxyborate and the like. Among these, lithium tricyanomethoxyborate, lithium tricyanoethoxyborate, lithium tricyanophenoxyborate, lithium tricyanobutoxyborate, and lithium tetracyanoborate are preferable. Particularly preferred is lithium tetracyanoborate.

  The electrolyte materials (i) and (ii) of the present invention may contain only the ionic compound represented by the general formula (1) and the medium or the ionic compound (1). An electrolyte other than (1) may be included. By using another electrolyte, the absolute amount of ions in the electrolyte material can be increased, and the electrical conductivity of the ion conductive material using the electrolyte material of the present invention can be improved.

As other electrolytes, those having a large dissociation constant in the electrolyte and having an anion that is difficult to solvate with an aprotic solvent described later are preferable. Examples of 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 onium cations. 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, and BF ₄ ⁻ is particularly preferable.

Specifically, alkali metal salts or 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 , LiN (CF ₃ Alkali metal salts and alkaline earth metal salts of perfluoroalkanesulfonic acid imides such as CF ₂ SO ₂ ) ₂ and LiN (FSO ₂ ) ₂ ; Alkali metal salts of hexafluorophosphoric acid such as LiPF ₆ , NaPF ₆ and KPF ₆ and alkaline earth metal salts; LiClO _4, NaClO ₄ perchlorate alkali metal salt or an alkaline earth metal such as salts; LiBF _4, tetrafluoroborate of NaBF _{4 such; LiAsF 6, LiI, LiSbF 6} , LiAlO 4, Alkali metal salts such as LiAlCl ₄ , LiCl, NaI, NaAsF ₆ , and KI; fourth of perchloric acid such as tetraethylammonium perchlorate Quaternary ammonium salts; quaternary ammonium salts of tetrafluoroboric acid such as (C ₂ H ₅ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₃ (CH ₃ ) NBF ₄ , and (C ₂ H ₅ ) ₄ NPF ₆ Quaternary ammonium salts; quaternary phosphonium salts such as (CH ₃ ) ₄ P · BF ₄ and (C ₂ H ₅ ) ₄ P · BF ₄ are preferred. 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.

  The abundance of the other electrolyte is preferably 0.1% by mass or 90% by mass or less in a total of 100% by mass of the ionic compound represented by the general formula (1) and the other electrolyte. It is. If the amount of other electrolytes is too small, it may be difficult to obtain the effect of using other electrolytes (for example, the absolute amount of ions is not sufficient and the electrical conductivity is reduced). When there is too much quantity, there exists a possibility that the movement of ion may be inhibited greatly. More preferably, it is 1 mass% or more, More preferably, it is 5 mass% or more, More preferably, it is 80 mass% or less, More preferably, it is 70 mass% or less.

<< Production Method of Electrolyte Material (i), (ii) >>
The production method of the present invention is a production method of the electrolyte materials (i) and (ii), wherein the ionic compound represented by the general formula (1) is selected from a lactone solvent and / or a carbonate solvent. After mixing with the solvent
(I) a step of performing distillation, and / or (ii) a step of contacting with a molecular sieve,
It has the characteristic in including.

  The ionic compound (1) contained in the electrolyte materials (i) and (ii) of the present invention has a very high affinity for water, and even if heating is continued at a temperature exceeding 100 ° C. under high vacuum, It is difficult to sufficiently reduce the amount of water contained in compound (1). Therefore, the present inventors have repeatedly studied on a method for reducing the amount of water, and can effectively reduce the amount of water by treating the ionic compound (1) in a state dissolved in an organic solvent. I found out. However, the organic solvent having a boiling point lower than that of water has a problem that the solvent is distilled off prior to the removal of water, and the organic solvent having a low solubility of the ionic compound (1) is in the middle of dehydration treatment. There is a problem that the ionic compound is precipitated on the surface, and it is difficult to sufficiently reduce the water content. Furthermore, it is conceivable to use a polar solvent from the viewpoint of solubility of the ionic compound, but in this case, the polar solvent remains in the ionic compound after drying. When the ionic compound contains a polar solvent, if it is used for electrochemical applications, problems such as generation of abnormal current due to decomposition of the solvent and deterioration of electrochemical characteristics such as reduction of ionic conductivity occur. Then, as a result of repeated further studies, the present inventors surprisingly, in a state where the ionic compound is dissolved in a solvent selected from a lactone solvent or a carbonate solvent used also as a solvent for an electrolyte solution, When (i) distillation step and / or (ii) contact step with molecular sieve can sufficiently reduce water content while preventing precipitation of ionic compound, and when used for electrochemical applications In addition, the present inventors have found that an electrolyte material in which electrochemical characteristics are hardly deteriorated can be obtained, and the present invention has been completed. Hereinafter, the synthesis method of the ionic compound (1) will be described in order.

  The ionic compound (1) according to the present invention may be synthesized by, for example, the method described in International Publication No. 2010/021391, etc. Specifically, the cyan compound and the boron compound are reacted. Can be manufactured.

Cyanide compound As the CN source of the ionic compound (1) represented by the general formula (1), it is preferable to use a cyanide compound. Examples of the cyanide include metal cyanides; ammonium cyanide compounds; silyl cyanides; hydrogen cyanide.

The metal cyanide, and inorganic cations Kt ₁ ^{m +} cyanide above. Preferred metal cyanides include KCN, NaCN, LiCN, Zn (CN) ₂ , Ga (CN) ₃ , Pd (CN) ₂ , Sn (CN) ₂ , Hg (CN) ₂ , Rh (CN) ₂ , Cu ( CN) ₂ and PbCN.

As the ammonium cyanide compound, an onium cation (for example, an ammonium cation represented by R ₄ N ⁺ ; a nitrogen-containing heterocyclic cation such as an imidazolium derivative or a pyrrolidinium derivative) and a cyanide ion (CN) are used. ^- )).

  Examples of silyl cyanides include trimethylsilyl cyanide, triethylsilyl cyanide, triisopropylsilyl cyanide, alkyldimethyl cyanide such as ethyldimethylsilyl cyanide, isopropyldimethylsilyl chloride, tert-butyldimethylsilyl cyanide; dimethylphenylsilyl cyanide; And alkylarylsilyl cyanides such as phenyldimethylsilyl cyanide.

  In addition, a commercially available thing may be used for a cyanide compound, and what was synthesize | combined by the well-known method may be used.

Boron compound A boron compound becomes a boron source of the ionic compound (1) based on this invention. Accordingly, the boron compound is not particularly limited as long as it contains boron. For example, ZBX ¹ ₄ (Z represents a hydrogen atom or an alkali metal atom, and X ¹ represents a hydrogen atom or a halogen atom. The same, and ZB (X ² R) ₄ (R is the same as the hydrocarbon group R in the general formula (1), and X ² is O or S. The same applies hereinafter), BX ¹ ₃ , BX ¹ ₃ -complex, B (X ² R) ₃ , B (X ² R) ₃ -complex, Na ₂ B ₄ O ₇ , ZnO.B ₂ O ₃ and at least one selected from the group consisting of NaBO ₃ Preferably there is.

The ^{_{ZBX 1 4, HBF 4, KBF}} 4, KBBr 4, LiBF 4, NaBH 4 , and examples of the _{^{ZB (X 2 R) 4,}} NaB (OH) 4, KB (OH) 4, LiB (OH ₄ ) and the like, and BX ¹ ₃ includes BH ₃ , BF ₃ , BCl ₃ , BBr ₃ , BI _{3 and the} like, and B (X ² R) ₃ includes boric acid; B (OMe) ₃ and _{B (OEt) 3, B (} O-i-Pr) 3, B (O-t-Bu) 3 ( Note,-t-indicates a "tert". _{Similarly.), B (OPh) 3} , B (OTMS) ₃ , B (O (C ₆ F ₅ )) ₃ , B (OCH (CF ₃ ) ₂ ) ₃ , B (On-Bu) ₃ , (-n- is “normal”. .. shown hereinafter the same) borate esters such as; B (SMe) ₃ and _{B (SEt) 3, B (} S-i-Pr) 3, B (S-t-Bu) 3, B ( Ph) ₃ Boric acid such as thioester; and the like, BX ¹ ₃ - _{^{complex, B (X 2 R) 3}} - The complex, diethyl ether, tripropyl ether, tri-butyl ether, tetrahydrofuran, ammonia, Methylamine, ethylamine, butylamine, hexylamine, octylamine, dimethylamine, diethylamine, dibutylamine, dihexylamine, dicyclohexylamine, trimethylamine, triethylamine, tributylamine, triphenylamine, guanidine, aniline, morpholine, pyrrolidine, methylpyrrolidine, etc. Examples include complexes of amines with the above BX ¹ ₃ or B (X ² R) ₃ . Among these, NaBH ₄ , BH ₃ , BF ₃ , BCl ₃ , BBr ₃ , B (OMe) ₃ , B (OEt) ₃ , B (SMe) ₃ , B (SEt) ₃ , Na having relatively high reactivity ₂ B ₄ O ₇ and B (OH) ₃ are preferable, and BF ₁ , BCl ₃ , BBr _3, etc., where X ¹ is a halogen atom, BX ¹ ₃ , B (OMe) ₃ , B (OEt) _3, etc. Boric acid ester ² in which R is O and R has an alkoxy group having 1 to 4 carbon atoms: B (OR) ₃ is more preferred, and most preferred are BCl ₃ , B (OMe) ₃ and B (OEt) ₃ Is mentioned. The said boron compound may be used independently and may be used in combination of 2 or more type.

  The blending ratio of the raw material may be changed in accordance with the number of cyano groups bonded to boron in the ionic compound (1). Thereby, from a monocyanoborate salt that is a monosubstituted cyano group, Dicyanoborate salt (disubstituted product), tricyanoborate salt (trisubstituted product), and tetracyanoborate salt that is tetrasubstituted product of cyano group can be obtained. For example, the amount of the boron compound used relative to the cyan compound is preferably 0.5: 1 to 100: 1 (cyan compound: boron compound, molar ratio). More preferably, the ratio is 0.8: 1 to 80: 1, still more preferably 1: 1 to 50: 1, still more preferably 1: 1 to 40: 1, and still more preferably 3: 1 to 1. 40: 1, particularly preferably 4: 1 to 20: 1, even more preferably 4: 1 to 10: 1, and most preferably 4: 1 to 5: 1. If the amount of the cyan compound is too small, the amount of the target ionic compound (1) may be reduced or a by-product may be formed. On the other hand, if the amount is too large, the amount of impurities derived from CN increases. The product tends to be difficult to purify.

  The reaction between the cyanide compound and the boron compound is preferably carried out in the presence of an organic or inorganic cation salt or an amine. In particular, when a metal cyanide is a cyanide, an amine or an organic or inorganic cation salt is used in the presence of an organic or inorganic cation salt, and when an alkylsilyl cyanide or alkylarylsilyl cyanide is a cyanide. When hydrogen cyanide is used as a cyanide in the presence of, it is recommended to carry out the reaction between the cyanide compound and the boron compound in the presence of an amine.

The organic cation constituting the salt of the organic or inorganic cation is preferably an ammonium cation represented by R ₄ N ⁺ ; a nitrogen-containing heterocyclic cation such as an imidazolium derivative. Examples of the inorganic cation include the inorganic cation Kt ₁ ^{m +} .

On the other hand, the anion constituting the salt of the organic or inorganic cation includes halide ion, hydroxide ion (OH ⁻ ), cyanate ion (OCN ⁻ ), thiocyanate ion (SCN ⁻ ), alkoxy ion (RO ⁻ ). Sulfate ion, nitrate ion, acetate ion, carbonate ion, perchlorate ion, alkyl sulfate ion, alkyl carbonate ion and the like. Among these, halide ions (F ⁻ , Cl ⁻ , Br ⁻ and I ⁻ ) are preferable, and among the halide ions, Cl ⁻ or Br ⁻ is particularly preferable.

  Preferred organic or inorganic cation salts include triethylammonium bromide, tributylammonium bromide, triethylmethylammonium bromide, 1-ethyl-3-methylimidazolium bromide, lithium bromide, triethylammonium chloride, tributylammonium chloride, triethylmethylammonium chloride, Examples include 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.

  Examples of the amine include chain amines such as triethylamine, tributylamine, butyldimethylamine, diethylamine, dibutylamine, butylamine, hexylamine, octylamine and guanidine, piperidine, 1,4-diazabicyclo [2.2.2] octane (DABCO ), Imidazoline, diazabicyclononene (DBN) and cyclic amines such as diazabicycloundecene (DBU), and aromatic amines such as pyridine, imidazole, methylimidazole and pyrazine.

  The amount of the organic or inorganic cation salt or amine compound used is preferably 100: 1 to 1: 100 (organic or inorganic cation salt or amine compound: boron compound, molar ratio) with respect to the boron compound. If the amount of organic or inorganic cation salt or amine used for the boron compound or the amount of amine used for hydrogen cyanide is too small, it may be difficult to efficiently produce the ionic compound (1), while if too much, The amount of impurities increases and purification may be difficult.

  In the above production method, a reaction solvent may be used. 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, 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 and valero Examples include nitrile, propylene 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.

  The conditions for reacting the above starting materials are not particularly limited and may be appropriately adjusted according to the progress of the reaction. For example, the reaction temperature is preferably 20 ° C to 180 ° C. More preferably, it is 40 degreeC-120 degreeC, More preferably, it is 50 degreeC-80 degreeC. The reaction time is preferably 1 hour to 50 hours, more preferably 5 hours to 40 hours, and even more preferably 10 hours to 30 hours.

  In the above manufacturing method, the order of adding and mixing the above-described raw materials is not particularly limited. In the case where an organic or inorganic cation salt or amine is used, a reaction solvent and an organic or inorganic cation salt or amine are mixed in advance, and then the remaining raw material boron compound and cyanide are added to the mixed solution. It is preferred to add the compound.

  After the reaction, purification may be performed to increase the purity of the produced ionic compound. Although the purification method is not particularly limited, for example, washing with water, organic solvents, and mixed solvents thereof, adsorption purification method, reprecipitation method, liquid separation extraction method, recrystallization method, crystallization method, and purification method by chromatography Is mentioned.

  The ionic compound obtained by the above production method may be further subjected to a cation exchange reaction in order to obtain an ionic compound (1) having a desired inorganic cation.

The cation exchange reaction may be performed by reacting the ionic compound obtained by the above production method with an ionic substance having a desired cation. As the ionic substance, any compound containing the above inorganic cation Kt ₁ ^{m +} may be used. For example, a hydroxide, a halogen salt, a tetrafluoroborate, a hexafluorophosphate, a peroxide of the inorganic cation Kt ₁ ^{m +} Examples include chlorate and bis (trifluoromethanesulfonyl) imide salt.

In the cation exchange reaction, a compound containing an onium cation Kt ₂ ^{m +} may be used as an ionic substance. In this case, an ionic compound (2) in which the cation is exchanged with an onium cation: Kt ₂ ^{m +} [B ⁻ _{(CN) 4-n Y n} ] m is obtained (wherein, Kt ₂ represents an onium cation, m, n and Y are same as the ionic compound (1)).

  Examples of the organic cation include onium cations described in International Publication No. 2010/021391 pamphlet. Preferred are quaternary ammonium and imidazolium, and particularly preferred are linear quaternary ammonium such as tetraethylammonium, tetrabutylammonium and triethylmethylammonium, linear such as triethylammonium, dibutylmethylammonium and dimethylethylammonium. Tertiary ammonium, imidazolium such as 1-ethyl-3-methylimidazolium and 1,2,3-trimethylimidazolium, N, N-dimethylpyrrolidinium and N-ethyl-N-methylpyrrolidinium Examples include pyrrolidinium.

  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.

  The timing for carrying out the cation exchange reaction is not particularly limited. Therefore, the cation exchange reaction may be performed subsequent to the synthesis reaction of the ionic compound (1), or may be performed after the contact step (ii) with the molecular sieve described later or the extraction step (iii). . In addition, since the effect by the extraction step (iii) is further enhanced in the case of an inorganic cation, the cation exchange reaction is preferably performed after the extraction step (iii).

  In the present invention, in order to obtain the electrolyte materials (i) and (ii), the ionic compound (1) obtained by the above synthesis method or the like is mixed with a solvent selected from a lactone solvent or a carbonate solvent, i) A distillation step of distilling the mixed solution, and / or (ii) a step of bringing the mixed solution into contact with the molecular sieve.

  Lactone solvents and carbonate solvents have higher solubility and higher boiling point of the ionic compound (1) than other solvents, so if a lactone solvent or a carbonate solvent is used, an ionic compound ( The moisture content can be efficiently reduced while suppressing the precipitation of 1). In addition, since the lactone solvent and the carbonate solvent are also used as a solvent for the electrolyte solution of various power storage devices, they may remain in the ionic compound (1) and further in the electrolyte materials (i) and (ii). , Which has little influence on the electrochemical properties. Furthermore, since the ionic compound (1) solution whose water content has been reduced through the step (i) and / or the step (ii) can be used as it is for an electric storage device such as an electrolytic solution, a process advantage is also obtained. be able to.

  Specific examples of the lactone solvent include γ-butyrolactone, γ-valerolactone, δ-valerolactone, γ-caprolactone, α-acetolactone, and β-propiolactone. One lactone solvent may be used alone, or two or more lactone solvents may be used in combination. Among the lactone solvents, γ-butyrolactone and γ-valerolactone are preferable.

Specific examples of the carbonate solvent include dimethyl carbonate (dimethyl carbonate), diethyl carbonate (diethyl carbonate), ethyl methyl carbonate (ethyl methyl carbonate), diphenyl carbonate, methyl phenyl carbonate, ethylene carbonate, propylene carbonate, and the like. A carbonate type solvent may be used individually by 1 type, and may be used in combination of 2 or more type. Among the carbonate solvents, propylene carbonate, ethylene carbonate, and ethyl methyl carbonate are preferable. In particular, for tetracyanoborates represented by n = 0 in the general formula (1), it is preferable to use a lactone solvent.
The lactone solvent and carbonate solvent may be used in combination as necessary.

  As the ionic compound (1) to be mixed with these solvents, a solution of the ionic compound (1) containing the solvent used in the synthesis or other purification process may be used as it is, or a part or all of the solvents may be used. After removal, it may be mixed with a lactone solvent or a carbonate solvent.

  The amount of the lactone solvent and / or carbonate solvent used is preferably 100 to 1,000,000 parts by mass with respect to 100 parts by mass of the ionic compound (1) or the ionic compound (1) contained in the solution. More preferably, they are 100 mass parts-100,000 mass parts, More preferably, they are 100 mass parts -10000 mass parts. If the amount of the solvent used is too small, the ionic compound may precipitate and it may be difficult to remove moisture sufficiently, and if it is too much, the productivity may decrease.

  The mixed solution of the ionic compound (1) and the lactone solvent and / or carbonate solvent may contain other solvents. The other solvent may be contained in the reaction solution, or may be mixed with the ionic compound (1) together with the lactone solvent and / or the carbonate solvent.

  Examples of the solvent used in the synthesis or other purification step and other solvents include (aromatic) hydrocarbon solvents such as hexane, cyclohexane and toluene, ester solvents such as ethyl acetate and butyl acetate, acetone and the like. Examples include ketone solvents such as ethyl methyl ketone, halogen-containing solvents such as chloroform, methylene chloride, chlorobenzene, and dichlorobenzene, nitrile solvents such as acetonitrile and valeronitrile, ether solvents, amide solvents, alcohol solvents, and the like.

  The amount of the other solvent is not particularly limited, but for the reason described above, the other solvent is distilled off in the process of performing the step (i) and / or (ii) (dehydration step) described later. In the end, it is recommended that the step (i) and / or (ii) be carried out with the ionic compound (1) dissolved in the lactone solvent and / or carbonate solvent. .

  Hereinafter, the steps (i) and (ii) will be described in order.

(I) About distillation process In this invention, after mixing the ionic compound represented by the said General formula (1), a lactone type solvent, and / or a carbonate type solvent, the said mixed solution is used for a distillation apparatus and distilled. I do. In the distillation step, the other solvent (such as the solvent used in the synthesis or purification step) and moisture contained in the mixed solution are distilled together with the lactone solvent and the carbonate solvent. The distillation operation that can be used in the present invention is not particularly limited, and may be a simple distillation type, a type using a thin-film distiller, a fractional distillation type provided with a distillation column, and a distillate from the distillation column at a constant reflux ratio. Examples include a distillation system that is extracted while returning to the inside of the column, a distillation system in which the distillation column is held at total reflux, moisture is concentrated in the reflux tank, and components are extracted in a short time when the components in the reflux tank are stabilized. Water can be further removed by repeating total reflux and batch extraction. The time for holding at the total reflux varies depending on the distillation equipment, but it is preferable to make it longer than the time for distilling twice the amount of liquid in the reflux tank from the top of the column. It is preferable that any apparatus used in the distillation step is equipped with a known heating means.

  The heating temperature of the mixed solution is preferably 30 ° C. or more and 250 ° C. or less, more preferably 40 ° C. or more and 200 ° C. or less, and further preferably 50 ° C. or more and 150 ° C. or less. If the temperature is too low, it may be difficult to reduce moisture sufficiently. On the other hand, if the temperature is too high, the ionic compound (1) and the solvent may be decomposed. The distillation may be performed under reduced pressure. This is because the water content can be reduced efficiently even at low temperatures by controlling the degree of vacuum. The degree of reduced pressure is, for example, preferably 20 kPa or less, more preferably 10 kPa or less, and further preferably 5 kPa or less.

  The implementation time of the distillation step is not particularly limited, and the distillation operation may be performed until the predetermined solvent distillate amount or the concentration of the ionic compound (1) reaches a desired value. Thereby, the ion conductive material (electrolytic solution) containing the ionic compound (1) of the desired density | concentration can be obtained.

(Ii) Contacting step with molecular sieve In the method (ii) of the present invention, the ionic compound represented by the general formula (1) and the lactone solvent are mixed, and then this mixed solution is brought into contact with the molecular sieve. A contact process is performed.

Here, the molecular sieve, the general _{formula: M 2 / n O · Al} 2 O 3 · xSiO 2 · yH 2 O (M is an alkali metal, a metal cation such as alkaline earth metals, n represents the valence of M And 1 to 2). The shape of the molecular sieve is not particularly limited, and any of powder, sphere (bead), column (pellet type), trisive type in which a plurality of columns are combined, and the like can be used. The molecular sieve may contain a binder component as long as it does not affect the electrochemical properties of the ionic compound, if necessary. As the molecular sieve, a synthesized one may be used, or a commercially available one may be used. Furthermore, you may use it, after giving a baking processing as needed. Specific molecular sieves include molecular sieves having an average pore diameter of 3 to 10 mm (notified value) based on 3A type, 4A type, 5A type, and 13X type. From the viewpoint of use in an electricity storage device, those having less elution components such as metal cations are preferred. Of these, those containing Li as the metal cation are preferably used because even if the metal cation derived from the molecular sieve remains after the contacting step, the performance of the electricity storage device is small. Moreover, in this invention, you may perform the process which replaces | exchanges the cation M contained in a molecular sieve for another metal cation as needed.

  The amount of molecular sieve used is not particularly limited, and can be appropriately determined according to the amount of water contained in the ionic compound or mixed solution. For example, molecular sieve 0 with respect to 100 parts by mass of the mixed solution. It is preferably 0.01 parts by mass to 10,000 parts by mass, more preferably 0.05 parts by mass to 1000 parts by mass, and still more preferably 0.1 parts by mass to 100 parts by mass. If the amount of molecular sieve used is too small, it may be difficult to reduce the amount of water sufficiently, and even if it is used in a large amount, it is difficult to see the effect of reducing the moisture in proportion to the amount used.

  The contact mode between the mixed solution and the molecular sieve is not particularly limited as long as the ionic compound (1) and the molecular sieve are in contact with each other. However, in order to obtain good dehydration efficiency, the mixed solution in contact with the molecular sieve is renewed. Is preferred. Specific contact modes include, for example, a mode in which the mixed solution and the molecular sieve are mixed and stirred; a mode in which the ionic compound solution is passed through the packed bed of the molecular sieve; and the like. In the embodiment in which the ionic compound solution is passed through the packed bed, the moisture content in the solution can be further reduced by repeatedly passing the same ionic compound solution through the packed bed as necessary. . Among the above-mentioned embodiments, the embodiment in which the ionic compound solution is passed through the packed bed of the molecular sieve needs to provide a separation step (solid-liquid separation step such as filtration, sedimentation separation, and centrifugal separation) between the ionic compound solution and the molecular sieve. The process is not complicated, and is particularly suitable for implementation at an actual operation level.

  The temperature at the time of bringing the mixed solution into contact with the molecular sieve is preferably -40 ° C to 200 ° C, more preferably -20 ° C to 100 ° C, and further preferably 0 ° C to 50 ° C. The contact time is not particularly limited, but is preferably 72 hours or less from the viewpoint of production efficiency, more preferably 24 hours or less, and even more preferably 6 hours or less.

  The used molecular sieve can be reused by heat treatment. The molecular sieve regeneration conditions include, for example, a method of heat treatment at 200 ° C. or higher under an inert gas flow such as nitrogen, a method of high temperature treatment after preheating at a lower temperature, and the like. It is not a thing.

  After the contact step with the molecular sieve, a solution containing the ionic compound (1) is obtained by performing solid-liquid separation as necessary.

  It is recommended that the above steps (i) and (ii) be carried out following the synthesis of the ionic compound and other purification steps. In addition, the water content reduction effect by the steps (i) and (ii) can be obtained even when the synthesis step is not performed. Therefore, when water is contained in the solid ionic compound (1), the ionicity obtained after being mixed with a lactone solvent and / or a carbonate solvent and dissolved or in a solution state. You may implement process (i) and (ii) about the solution of compound (1). In addition, although the reduction effect of moisture content is fully acquired by implementing either process (i) or (ii), you may implement combining these processes.

  By performing the said process (i) or (ii), the solution containing the ionic compound (1) by which water content was reduced to 50 ppm or less is obtained. Since the solution containing this ionic compound (1) has a reduced water content, it can be used in various applications as it is. That is, according to the present invention, an increase in the amount of water derived from the solvent can be prevented as compared with the case where the solid ionic compound is dissolved in the solvent. Since the lactone solvent and / or the carbonate solvent correspond to the medium, the ionic compound (1) solution obtained through the step (i) or (ii) is the (electrolyte material (i )).

  In the production method of the present invention, in place of the steps (i) and (ii) or in addition to the steps (i) and (ii), the ionic compound (1) or (2) is phase-separated from water. The step (iii) of extracting with a mixed solvent obtained by mixing an organic solvent and water in a predetermined ratio may be performed. In the extraction step (iii) according to the present invention, two or more extraction operations are performed using mixed solvents A and B having different mixing ratios of water and an organic solvent that is phase-separated from water.

  In general, in organic synthesis, methods such as washing of a crude product with an organic solvent or water and a solvent extraction method in which the product is extracted by dissolving the product in an organic solvent are employed as means for purifying the target compound. Also in the present invention, a method of extracting the ionic compound in the organic solvent and the impurities in water by bringing the synthesized reaction solution into contact with an organic solvent for phase separation from water has been adopted. However, while repeatedly examining the method for producing the electrolyte material, after extracting the ionic compound into the organic solvent (the first extraction step), using an extraction solvent in which the mixing ratio of the solvent is reversed from the first extraction step. It has been surprisingly found that by performing the extraction operation (that is, extracting the ionic compound into the aqueous phase), an electrolyte material with a reduced amount of impurities and moisture content can be obtained. The reason why the amount of impurities and water content are reduced is not completely understood, but impurities produced as a by-product during the production of ionic compounds include not only compounds that are easily dissolved in water but also organic solvents. Since there are compounds that are easily soluble, the components that have been separated from other impurities together with the ionic compound are different from those of the ionic compound by performing an extraction operation in which the mixing ratio of the organic solvent and water is changed. We believe that impurities are removed from the ionic compounds as a result of partitioning into the phases. Moreover, since the separated impurity is a substance that easily retains water, it is presumed that moisture accompanying the impurity is removed together with the impurity, and the moisture content of the ionic compound is reduced.

  Reduction of the water content of the ionic compound (1) leads to a reduction of the water content of the electrolyte materials (i) and (ii), and as a result, the withstand voltage characteristics of the electrolyte solution using the electrolyte material according to the present invention. Contributes to the suppression of the decrease in Further, by reducing the amount of impurities, it is possible to fully utilize the characteristics such as heat resistance inherent in the ionic compound (1). Therefore, the thermal decomposition start temperature of the ionic compound according to the present invention obtained through the extraction step (iii) is 500 ° C. or higher. Further, when the ionic compound (2) having an onium cation is synthesized from the ionic compound (1) obtained through the extraction step (iii) as a raw material, the pyrolysis start temperature is similarly improved. As seen, the ionic compound (2) having the onium cation has a thermal decomposition starting temperature of 375 ° C. or higher.

The organic solvent is not particularly limited as long as it is a solvent that is phase-separated from water, and examples thereof include ethers such as dimethyl ether, diethyl ether, dipropyl ether, methyl-tert-butyl ether, butyl ethyl ether, cyclopentyl methyl ether, and tetrahydropyran. Solvents: ester solvents such as methyl acetate, ethyl acetate, isopropyl acetate, butyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl acrylate, methyl methacrylate; methyl butyl ketone, methyl isobutyl ketone, diethyl ketone Ketone solvents such as ethyl butyl ketone, ethyl isobutyl ketone and cyclohexanone; chloromethane, dichloromethane, trichloromethane, tetrachloromethane, dichloroethane, trichloroethane, teto Halogenated hydrocarbon solvent in which part or all of hydrogen such as lachloroethane is substituted with halogen (1 to 10 carbon atoms); Fluoroether such as bis (trifluoromethyl) ether, bis (pentafluoroethyl) ether; Hydrofluoroethers such as C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , C ₁₀ F ₂₁ OCH ₃ , CF ₃ OCH ₃ ; n-butyronitrile, isobutyronitrile, valeronitrile, benzonitrile, tolunitrile, etc. Nitrile solvents of: alcohol solvents such as octanol, nonanol, decanol; aromatic hydrocarbon solvents such as benzene, toluene, xylene, mesitylene, ethylbenzene, n-butylbenzene, isobutylbenzene; n-pentane, n-hexane, Methyl pentane, n-heptane, methyl hexane, dimethyl pen And aliphatic hydrocarbon solvents such as tan, n-octane, methylheptane, dimethylhexane, trimethylpentane, dimethylheptane, n-decane, cyclohexane, and cycloheptane. Among these, dimethyl ether, diethyl ether, dipropyl ether, methyl tert-butyl ether, ethyl acetate, isopropyl acetate, butyl acetate, methyl propionate, methyl butyl ketone, methyl isobutyl ketone, cyclohexanone, chloromethane, dichloromethane, trichloromethane, Tetrachloromethane, hydrofluoroether, isobutyronitrile, valeronitrile, toluene, xylene, n-hexane are preferred, diethyl ether, dipropyl ether, ethyl acetate, isopropyl acetate, butyl acetate, dichloromethane, valeronitrile, xylene, n -Hexane is more preferred. In addition, it is one of preferred embodiments of the present invention to use a mixture of two or more of the above organic solvents.

  On the other hand, the water used in the extraction step (iii) preferably has a low impurity content. For example, it is recommended to use ultrapure water (over 18.2 Ω · cm), distilled water, deionized exchange water, or the like. Is done.

  In the mixed solvent A used in the extraction step (iii), the mixing ratio of the organic solvent to be phase-separated with water and water is preferably 20: 1 to 2: 1 by mass ratio. More preferably, it is 15: 1-3: 1, More preferably, it is 10: 1-5: 1. On the other hand, in the mixed solvent B, the mixing ratio of the organic solvent that phase separates from water and water is preferably 1: 2 to 1:20 by mass ratio, more preferably 1: 3 to 1:15, More preferably, it is 1: 5 to 1:10. Thus, impurities can be efficiently removed from the ionic compound by using the mixed solvents A and B in which the mixing ratio of the organic solvent and water is reversed. In addition, when there are too many organic solvents or too few, it will become difficult to implement stable extraction operation. The said mixing ratio means the mixing ratio of the organic solvent and water in the system which implements extraction operation (extraction process).

  The number of extraction operations with the mixed solvents A and B is not particularly limited and may be appropriately determined according to the situation at the time of production. For example, each of the extraction operations with the mixed solvents A and B is performed once or more. It is preferable, more preferably 2 times or more, still more preferably 3 times or more. In addition, since excessive repetition of extraction operation may reduce the amount of ionic compounds, it is preferable to perform extraction operation with mixed solvents A and B 20 times or less each. More preferably, it is 15 times or less, More preferably, it is 10 times or less. Moreover, it is preferable to set it as 40 times or less as a whole (more preferably 30 times or less, and further preferably 20 times or less).

  The extraction step (iii) according to the present invention only needs to include an extraction step with the mixed solvent A and an extraction step with the mixed solvent B, and the order of performing the extraction steps with the mixed solvents A and B is not particularly limited. Therefore, after performing the extraction process with the mixed solvent A with a large amount of organic solvent, the extraction process with the mixed solvent B with a small amount of organic solvent may be performed, and conversely, the extraction process with the mixed solvent B with a small amount of organic solvent. After that, an extraction step using a mixed solvent A having a large amount of organic solvent may be performed. In addition, when the extraction operation with the mixed solvents A and B is performed twice or more, after the extraction operation with the mixed solvent A is repeated (after the extraction step with the mixed solvent A), the extraction step with the mixed solvent B is performed. Alternatively, the extraction operation with the mixed solvents A and B may be performed alternately. Preferably, after performing the extraction step with the mixed solvent A, the extraction step with the mixed solvent B is performed.

  Although the timing of performing the extraction step (iii) is not particularly limited, from the viewpoint of further reducing the water content of the electrolyte material, the step (i) or the step (ii) is performed immediately after the synthesis of the ionic compound. In some cases, it is recommended that the extraction step (iii) be performed before the steps (i) and (ii).

  After the step (i) and / or step (ii), or after the step (iii) optionally performed, it is obtained for the purpose of enhancing the stability during storage or facilitating the distribution of the product. The solvent may be distilled off from the obtained ionic compound (1) solution to obtain a solid ionic compound. The solid ionic compound here corresponds to the electrolyte material (ii).

  The method for obtaining the solid ionic compound (1) is not particularly limited. For example, (a) the ionic compound (1) solution is heated until the ionic compound (1) is precipitated, and the precipitate is separated. A method of drying to form a solid (powder); (b) the lactone solvent and / or carbonate solvent from the solution of the ionic compound (1) and concentrating, and then cooling the concentrate while cooling if necessary. And depositing the ionic compound (1), separating, drying and solidifying it; (c) adding a solvent to the concentrated liquid to precipitate the ionic compound (1), Method of separating and drying to solidify; (d) A method of adding a poor solvent having a higher boiling point and distilling off the lactone or carbonate solvent to solid-liquid separate the slurry; (e) The solvent is removed Heat the ionic compound (1) solution to dryness That method; and the like.

  The drying method of an ionic compound (1) is not specifically limited, A conventionally well-known drying apparatus can be used. The drying temperature is preferably 0 ° C to 400 ° C. More preferably, it is 10 degreeC or more, More preferably, it is 20 degreeC or more, More preferably, it is 300 degreeC or less, More preferably, it is 200 degreeC or less.

  Moreover, you may perform drying of ionic compound (1), supplying gas to a drying apparatus. Examples of usable gas include dry inert gas such as nitrogen and argon, and dry air.

≪Usage≫
The electrolyte materials (i) and (ii) of the present invention containing the ionic compound (1) have a reduced water content. Therefore, the electrolyte materials (i) and (ii) of the present invention include, in addition to batteries having charging and discharging mechanisms such as primary batteries, lithium (ion) secondary batteries, fuel cells, etc., electrolytic capacitors, electric double layer capacitors, solar cells It is expected to be used as a conductivity-imparting agent for polymers using electrochemical materials such as electrolytes provided in various power storage devices such as batteries, and having both electrochemical characteristics and thermal stability. Note that the structure of the electricity storage device is not particularly limited, and the electrolyte material of the present invention can be applied to a known electricity storage device.

  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]
¹ H-NMR and ¹³ C-NMR spectra were measured using “Unity Plus” (400 MHz) manufactured by Varian, and the structure of the sample was analyzed based on the peak intensity of proton and carbon. ^For measurement of ⁷ Li-NMR and ¹¹ B-NMR spectra, “Advance 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 ⁷ Li-NMR spectrum, lithium chloride is used as the standard substance, and in the measurement of ¹¹ B-NMR spectrum, 1 -Ethyl-3-methylimidazolium tetrafluoroborane was quantified as a calibration standard.

[Measurement of water content]
Using the Karl Fischer moisture measuring device “AQ-2100” manufactured by Hiranuma Sangyo Co., Ltd., an ionic compound (electrolyte material (ii)) obtained in the following experimental example, or an electrolytic solution containing the ionic compound (electrolyte material) (I)), and the amount of water contained in the organic solvent was measured. In addition, about a series of operation, such as handling of an ionic compound or an ion conductive material, and a measurement of water content, it was performed in a dry room (temperature: 25 ° C., dew point: −70 ° C. to −50 ° C.). The sample injection amount is 0.1 ml to 3 ml depending on the moisture content of the sample, “Hydranal (registered trademark) Chromat AK” (manufactured by Sigma Aldrich) is used as the generation solution, and “hydra” is used as the counter electrode solution. "Nar (registered trademark) Chromat CG-K" (manufactured by Sigma Aldrich) was used. The sample was injected from the sample inlet using a syringe so as not to touch the outside air.

  The water content of the solution containing the ionic compound (1) (electrolyte material (i) in the present invention) was measured with the Karl Fischer moisture measuring apparatus using the ionic compound obtained in the following experimental example as a sample. For the ionic compound (1) in the solid state, the moisture content is measured for a sample solution prepared by dissolving in a solvent whose moisture content has been measured in advance, and the solvent content is determined from the moisture content (measured value) in the measured solution. The water content in the solid (ionic compound (1)) was calculated by subtracting the amount of water derived from. In addition, when a polymer is included as a medium of the electrolyte material (i), it can be measured by being dispersed in a solvent in the same manner as the solid ionic compound (1).

[Measurement of impurity content]
The amount of impurities contained in the ionic compound obtained in the production example was measured. The measuring method of various impurities is as follows.
[1] Measurement of CN ^- content 10 mg of the ionic compound obtained in the following production example was diluted 100-fold, 1000-fold or 10000-fold with ultrapure water (over 18.2 Ω · cm) to obtain a measurement solution, which was free The amount of cyan contained in the compound was measured using a simple pack for cyanide measurement (Shibata Kagaku Co., Ltd., 4-pyridinecarboxylic acid method).
[2] Measurement of metal and metalloid component content 0.1 g of the ionic compound obtained in the following production example was diluted 100-fold or 200-fold with ultrapure water (over 18.2 Ω · cm) to obtain a measurement solution. The amount of Na, Li, K, and Fe contained in the sample was measured using an ICP emission spectrometer ICPE-9000 (manufactured by Shimadzu Corporation). The quantitative limit (lower limit) is 10 ppm.

Production Example 1 Production of lithium tetracyanoborate 44.4 g (200 mmol) of tributylammonium chloride previously heated and dried was placed in a 1 L flask equipped with a stirrer, a reflux tube and an extraction device, and a dropping funnel. Was replaced with nitrogen gas, and then 109.0 g (1100 mmol) of trimethylsilylcyanide (TMSCN) was added at room temperature and stirred. Next, 200 mL (200 mmol) of a 1 mol / L p-xylene solution of boron trichloride was slowly dropped from the dropping funnel. After completion of the dropwise addition, the reaction vessel was heated to 150 ° C., and the reaction was carried out while extracting by-product trimethylsilyl chloride (TMSCl, boiling point: about 57 ° C.) from the reflux extraction portion.

  After stirring with heating for 30 hours, the inside of the reaction vessel was depressurized with a vacuum pump, and the excess TMSCN p-xylene solution was distilled off from the reflux outlet. Then, in a 500 mL beaker equipped with a stirrer, 45 g of the crude product and 225 g of ethyl acetate were added and dissolved by stirring for 5 minutes, and then activated carbon (Calboraphin (registered trademark) manufactured by Nippon Environmental Chemical Co., Ltd.) was added. Stir for 10 minutes. The obtained activated carbon suspension was filtered through a membrane filter (0.2 μm, PTFE), the solvent was distilled off from the filtrate and dried to obtain tributylammonium tetracyanoborate (yellow solid) (yield: 48. 2 g, 160 mmol, yield: 80%).

Next, in a 500 mL beaker equipped with a stirrer, 48.2 g (160 mmol) of the obtained tributylammonium tetracyanoborate, 200 g of butyl acetate, 4.6 g (192 mmol) of lithium hydroxide monohydrate and 200 g of ultrapure water were obtained. Was added and stirred for 1 hour. Thereafter, the mixed solution was transferred to a separatory funnel and allowed to stand to separate into two layers. A light yellow solid obtained by separating and concentrating the lower layer (aqueous layer) was mixed with 200 g of acetonitrile and stirred. Thereafter, the obtained solution was filtered through a membrane filter (0.2 μm, manufactured by PTFE), the solvent was distilled off from the filtrate, and the resultant was dried under reduced pressure at 150 ° C. for 3 days, whereby the target lithium tetracyanoborate (LiTCB, (White solid) was obtained (yield: 13.6 g, 112 mmol, yield: 70%, water content: 872 ppm).
⁷ Li-NMR (d6-DMSO) δ0.02 (s)
¹³ C-NMR (d6-DMSO) δ 121.9 (m)
¹¹ B-NMR (d6-DMSO) δ-39.6 (s)

Experimental example 1
Experimental Example 1-1
Lithium tetracyanoborate (LiTCB, solid) 2.50 g (water content: 872 ppm) obtained in Production Example 1 was dissolved in 497.53 g of γ-butyrolactone having a water content of 12.8 ppm to obtain a uniform mixed solution. did. The water content of the solution at this time was 17.1 ppm. The mixed solution was supplied to a 500 ml eggplant flask, and the mixed solution was heated and stirred under a pressure of 1.5 kPa while performing simple distillation. The distillation temperature at this time was 81 degreeC. Distillation was completed when 454.3 g of solvent (90% by mass of the mixed solution) was distilled off. At this time, the water content in the LiTCB solution was 8.1 ppm, and the LiTCB concentration was 5.7% by mass. Further, the remaining solvent was distilled off under reduced pressure, and the resulting precipitate was vacuum-dried at 150 ° C. for 1 day to obtain LiTCB (solid) having a water content of 127 ppm (yield: 2.48 g). Linear sweep voltammetry (LSV) measurement was performed using the obtained LiTCB.

[Linear sweep voltammetry (LSV) measurement]
The sample obtained in Experimental Example 1-1 was dissolved in γ-butyrolactone (water content 11.7 ppm) to prepare a sample solution having a LiTCB concentration of 7 mass% and a water content of 19.8 ppm. This sample solution was subjected to LSV measurement using a tripolar electrochemical cell and a standard voltammetric tool (“HSV-100”, manufactured by Hokuto Denko). In this experimental example, ² mA / cm ² was taken as a reference current value, and when a current value exceeding ² mA / cm ² was observed, it was determined that deterioration of the electrolyte or electrode occurred (decomposition current value). . The results are shown in FIG. The measurement conditions are as follows.

Measurement conditions Working electrode: Glassy carbon electrode (manufactured by BAS, product number: 11-2411, electrode surface area 1 mmφ (0.785 mm ² ))
Reference electrode: Ag electrode (Reference solution: acetonitrile solution of silver nitrate and tetrabutylammonium perchlorate (silver nitrate concentration 0.01M, tetrabutylammonium perchlorate concentration 0.1M))
Counter electrode: platinum electrode Salt bridge: 0.1 M acetonitrile solution of tetrabutylammonium perchlorate Solvent: γ-butyrolactone Sweep speed: 100 mV / sec
Sweep range: Natural potential to 10 V (vs. Ag / Ag ⁺ )

In the measurement method, an Ag electrode is used as a reference electrode (Ag / Ag ⁺ , standard electrode potential: 0.799 V). Therefore, when this is converted into a case where Li metal is used as a reference electrode (Li / Li ⁺ , standard electrode potential: −3.045 V), the sweep range is 3.8 V to 13.8 V.

Experimental Example 1-2
Lithium tetracyanoborate (LiTCB) 0.1 g (water content: 627 ppm) synthesized in the same manner as in Production Example 1 was dissolved in γ-butyrolactone having a water content of 11.7 ppm, and the water content was 55.6 ppm. A measurement sample (LiTCB concentration of 7% by mass) was prepared. For this sample, linear sweep voltammetry (LSV) measurement was performed in the same manner as in Experimental Example 1-1. The results are shown in FIG.

From FIG. 1, the peak current value is reduced in the case of Experimental Example 1-1 (water content: 127 ppm) having a low water content compared to Experimental Example 1-2 (water content: 627 ppm). (Experimental example 1-1: about 1.4 mA / cm ² , Experimental example 1-2: about 2.5 mA / cm ² ). From this, the water content can be reduced by performing distillation after mixing the ionic compound and the lactone solvent, and the water content can be 500 ppm or less (electrolyte material (ii)) or 50 ppm or less. It can be seen that withstand voltage characteristics can be improved by using (electrolyte material (i)).

Experimental Example 1-3
A uniform sample solution was prepared by dissolving 50.1 g (water content: 754 ppm) of lithium tetracyanoborate (LiTCB) synthesized in the same manner as in Production Example 1 in 950.03 g of γ-butyrolactone having a water content of 26.8 ppm. Obtained. The LiTCB concentration of the obtained sample solution was 5.0% by mass, and the water content of the solution was 63.2 ppm. When the sample solution was distilled under the same conditions as in Experimental Example 1-1 and the change in solution moisture content over time was confirmed, the solution moisture content when the LiTCB concentration reached 6.1% by mass was 11.0 ppm. Further, when the distillation was continued and the LiTCB concentration reached 7.0 mass%, the water content of the solution was 10.6 ppm. The LiTCB concentration in the solution was calculated from the amount of γ-butyrolactone distilled off from the sample solution up to the sampling of the sample for measuring the water content and the amount of the sample solution before distillation. Thereafter, the distillation was further continued. When 30% by mass of γ-butyrolactone in the sample solution was distilled off, the distillation was terminated, and the remaining solvent was distilled off under reduced pressure. The obtained precipitate was vacuum-dried at 150 ° C. for 1 day to obtain LiTCB (solid) (yield: 49.9 g, water content: 141 ppm).

  From the result of Experimental Example 1-3, even when the concentration of the sample solution LiTCB subjected to the distillation step is high (Experimental Example 1-1: 0.5 mass%, Experimental Example 1-3: 5 mass%), Experimental Example 1-1 It can be seen that the amount of water can be reduced as in the case where the LiTCB concentration is low.

Experimental example 2
Lithium tetracyanoborate (LiTCB) 5.67 g (water content: 836 ppm) obtained in the same manner as in Production Example 1 was dissolved in 75.12 g of γ-butyrolactone having a water content of 12.8 ppm to obtain a uniform sample solution. Obtained. The obtained sample solution had a water content of 70.6 ppm.

  Next, in a dry room at a temperature of 25 ° C. and a dew point temperature of −70 ° C. to −50 ° C., about 15 g of the sample solution and 10% by mass of various molecular sieves (made by Union Showa Co., Ltd.) ) In a polypropylene screw tube and sealed, and stirred in a shaker (SHAKER RS-2, manufactured by ASONE Corporation) in an environment of temperature: 25 ° C. and dew point: −70 ° C. to −50 ° C. However, the moisture content of the sample solution was measured at regular intervals, and the transition was observed. The results are shown in Table 1.

Molecular sieve 1: Molecular sieve having sodium cation and calcium cation (model number “3A SDG”, average pore diameter (notified value): 3 mm, spherical, made by Union Showa Co., Ltd.)
Molecular sieve 2: Molecular sieve having sodium cation (model number “4A SDG”, average pore diameter (notified value): 4 mm, spherical, made by Union Showa Co., Ltd.)
Molecular sieve 3: Molecular sieve having sodium cation and calcium cation (model number “5A SDG”, average pore size (notified value): 5 mm, spherical, made by Union Showa Co., Ltd.)
Molecular sieve 4: Molecular sieve having lithium cation and sodium cation (model number “Li-X SDG”, average pore diameter (notified value): 10 mm, spherical, made by Union Showa Co., Ltd.)

When the LiTCB concentration in the sample solution was measured by ¹¹ B-NMR simultaneously with the measurement of the water content, the LiTCB concentration was measured before and after contact with the molecular sieve in any of Experimental Examples 2-1 to 2-4. There was no change, and it was confirmed that the ionic compound (1) was not adsorbed on the molecular sieve.

  From the results in Table 1, it can be seen that the amount of water can be reduced to a level sufficient to be used as a conductive material while maintaining the ionic compound concentration by contact with the molecular sieve.

Production Example 2 Synthesis of lithium tricyanomethoxyborate (LiB (CN) ₃ OMe) 109 g (600 mmol) of triethylammonium bromide was added to a 1 L three-necked flask equipped with a thermometer, a stirrer, and a dropping funnel. Was replaced with nitrogen gas. To this, 300 mL of 1,2-dichloroethane was added, and then 62.3 g (600 mmol) of trimethyl borate was added at room temperature (25 ° C.). Next, while stirring the obtained mixed solution, 238 g of trimethylsilylcyanide (2400 mmol, 4.0 equivalent to the boron compound) was added dropwise at room temperature, and then the mixed solution was heated to 60 ° C. with an oil bath. The mixture was stirred at the same temperature for 15 hours to be reacted.

  Thereafter, the organic solvent was distilled off under reduced pressure from the obtained yellow reaction solution, and the mixture was concentrated and cooled to room temperature. Thus, yellow oily triethylammonium tricyanomethoxyborate (crude) was obtained.

Next, after adding the obtained triethylammonium tricyanoborate and 574 g of pure water to a 1 L eggplant flask containing a stirring bar, 30.2 g (720 mmol) of lithium hydroxide monohydrate was added thereto at room temperature. The mixture was stirred and stirred at the same temperature for 4 hours to carry out the reaction.
The solvent was distilled off from the obtained yellow reaction solution under reduced pressure and concentrated. The concentrated solution was cooled to room temperature, and then the concentrated solution and 1567 g of ethyl acetate were mixed in a separatory funnel, and shaken and stirred. The product was extracted. After separating the organic layer from the aqueous layer, ethyl acetate was distilled off to obtain a light yellow solid lithium tricyanomethoxyborate (crude) (yield: 45.3 g, yield: 59.5%).

  Next, in a separatory funnel, the obtained lithium tricyanomethoxyborate was dissolved in 228 g of a 5 mass% lithium hydroxide aqueous solution, and further 2273 g of butyl acetate was added, followed by shaking and stirring to extract the product into an organic layer. did. After separating the organic layer from the aqueous layer, butyl acetate was distilled off. This operation was repeated twice to obtain white solid lithium tricyanomethoxyborate (cleaned product) (yield: 25.3 g).

To the obtained lithium tricyanomethoxyborate, 160 g of dehydrated acetonitrile was added and heated to 70 ° C. to obtain a homogeneous solution. The solution was allowed to stand at −20 ° C. overnight. After standing, the solid precipitated at the bottom of the flask was filtered to obtain white crystals of lithium tricyanomethoxyborate (recrystallized primary crystal). The filtrate was collected, acetonitrile was distilled off, and the recrystallization operation described above was performed again to obtain secondary crystals (total yield: 16.6 g, 131 mmol, total yield 22%, water content: 531 ppm). . Table 2 shows the amounts of various impurities contained in the product.
¹ H-NMR (d6-DMSO) δ 3.16 (q, J = 3.6Hz, 3H)
¹³ C-NMR (d6-DMSO) δ 8.80, 49.9, 52.7, 127.7 (q, J = 69.5Hz)
¹¹ B-NMR (d6-DMSO) δ-18.6 (s)

Production Example 3 Synthesis of Lithium Tricyanoethoxyborate (LiB (CN) ₃ OEt) Same as Production Example 2 except that 72.7 g (498 mmol) of triethyl borate was used instead of trimethyl borate in Production Example 2. The reaction and purification were carried out under the conditions described above to obtain white crystalline lithium tricyanoethoxyborate (recrystallized product) (yield: 30.3 g, 215 mmol, total yield: 43%, water content: 593 ppm). Table 2 shows the contents of various impurities contained in the product.
¹ H-NMR (d6-DMSO) δ 1.12 (t, J = 7.2Hz, 3H), 3.37-3.38 (m, 2H)
¹³ C-NMR (d6-DMSO) δ 17.4, 60.5, 128.0 (q, J = 69.7 Hz)
¹¹ B-NMR (d6-DMSO) δ-19.2 (s)

  In Table 2, “x” indicates that the upper limit of the content was exceeded (Li ion: more than 20000 ppm), and “ND” indicates that it was less than the detection limit (lower limit). In Production Examples 2 and 3, Li corresponds to a cation constituting an ionic compound, and thus is not regarded as an impurity.

Experimental example 3-1
1.01 g (water content: 531 ppm) of lithium tricyanomethoxyborate (LiB (CN) ₃ OMe, recrystallized product) obtained in Production Example 2 was converted to 9.61 g of γ-butyrolactone having a water content of 12.8 ppm. Dissolved to obtain a uniform sample solution. The water content of the sample solution at this time was 62.1 ppm.

  Next, in the same manner as in Experimental Example 2, in a dry room at a temperature of 25 ° C. and a dew point temperature of −70 ° C. to −50 ° C., 33% by mass of molecular sieve 2 (33% by mass with respect to the mass of the sample solution) A molecular sieve having a sodium cation, model number “4A SDG”, average pore size (notified value): 4 mm, spherical, Union Showa Co., Ltd.) is placed in a polypropylene screw tube and sealed, temperature: 25 ° C., dew point : Under an environment of −70 ° C. to −50 ° C., the mixture was stirred for 24 hours with a shaker (SHAKER RS-2, manufactured by ASONE Corporation), and the water content was measured. The results are shown in Table 3.

Experimental Example 3-2
1.12 g (water content: 593 ppm) of lithium tricyanoethoxyborate (LiB (CN) ₃ OEt, recrystallized product) obtained in Production Example 3 was dissolved in 9.20 g of γ-butyrolactone to obtain a uniform sample solution Got. The moisture content of the sample solution at this time was 75.8 ppm.

  Next, in the same manner as in Experimental Example 3-1, in a dry room having a temperature of 25 ° C. and a dew point temperature of −70 ° C. to −50 ° C., the sample solution and 33% by mass of the molecular sieve 2 with respect to the mass of the sample solution Is put into a polypropylene screw tube and sealed, and stirred for 24 hours with a shaker (SHAKER RS-2, manufactured by ASONE CORPORATION) in an environment of temperature: 25 ° C. and dew point temperature of −70 ° C. to −50 ° C. The water content was measured. The results are shown in Table 3.

  From Table 3, it can be seen that in any of Production Examples 2 and 3, the amount of water can be reduced to a level sufficient to be used as a conductive material while maintaining the ionic compound concentration by contact with the molecular sieve. .

Experimental Example 4 Synthesis of Lithium Tetracyanoborate (LiTCB: Li [B (CN) ₄ ]) After replacing the inside of a 500 ml three-necked flask equipped with a stirrer, a reflux tube and a withdrawal device, and a dropping funnel with nitrogen, 41.3 g (227 mmol) of triethylammonium bromide that had been dried by heating, 25.3 g (216 mmol) of boron trichloride, and 132.8 g of chlorobenzene were added, and the mixed solution was heated to 80 ° C. with stirring. 90.1 g (908 mmol) of trimethylsilylcyanide was added dropwise thereto over 2 hours, and the mixture was stirred at 80 ° C. for 13 hours. Thereafter, reaction by-products and an excess amount of trimethylsilylcyanide were distilled off from the reflux outlet under reduced pressure.

To the obtained black solution, 13.6 g (324 mmol) of lithium hydroxide monohydrate and 270 g of ultrapure water were added at room temperature, and the mixture was stirred at room temperature for 30 minutes. Thereafter, the mixture was heated to 80 ° C. to remove unreacted triethylammonium tetracyanoborate (Et ₃ NHTCB) under reduced pressure. To the resulting solution was added 2700 g of butyl acetate, transferred to a separatory funnel, and a liquid separation operation was performed. It was. To the obtained butyl acetate phase, 270 ml of 3% by weight lithium hydroxide aqueous solution was added, and the contact step of butyl acetate and water with a mixed solvent having a mixing ratio of 10: 1 was performed twice (extraction step with mixed solvent A). The obtained butyl acetate phase was concentrated and dried to obtain crude LiTCB.

175 g of water and 17.5 g of butyl acetate were added to the obtained crude LiTCB, and a liquid separation operation was performed again to separate an aqueous phase. 17.5 g of butyl acetate was added to the obtained aqueous phase, and the operation of separating the aqueous phase in the same manner was repeated 5 times (extraction step using mixed solvent B), and the obtained aqueous phase was concentrated and dried to obtain LiTCB. (Yield: 18.4 g (151 mmol), Yield: 70%). At this time, the butyl acetate phase separated from the aqueous phase contained a blackish brown substance.
The water content of the obtained LiTCB was 358 ppm. The results of various NMR analyzes were the same as those obtained in Production Example 1.

Experimental Example 5
To a beaker equipped with a stirrer, 0.6 g (4.9 mmol) of LiTCB obtained in Experimental Example 4 was added, and 6 g of ultrapure water and 0.94 g of 1-ethyl-3-methylimidazolium bromide (EMImBr) were added thereto. (4.9 mmol) was added at room temperature (25 ° C.). After stirring for 30 minutes at the same temperature, 24 g of butyl acetate was added thereto, the product was extracted into butyl acetate, and this butyl acetate phase was washed twice with 6 g of ultrapure water. After washing, the butyl acetate phase was concentrated and dried to obtain EMImTCB as a colorless transparent liquid (yield: 1.09 g (4.8 mmol), yield: 98%). The obtained EMImTCB had a water content of 88 ppm.
¹ H-NMR (d6-DMSO) δ 8.41 (s, 1H), 7.34 (d, J-21.6Hz, 2H), 3.81 (s, 3H), 1.45 (t, J = 7.2Hz, 3H)
¹³ C-NMR (d6-DMSO) δ 136.5 (s), 132.2 (m), 122.9 (s), 45.8 (s), 36.8 (s), 15.4 (s)
¹¹ B-NMR (d6-DMSO) δ-39.6 (s)

Experimental Example 6
EMImTCB was obtained in the same manner as in Experimental Example 5, except that 0.6 g (4.9 mmol) of LiTCB obtained in Production Example 1 was used. (Yield: 1.01 g (4.5 mmol), Yield: 92%)
When LiTCB obtained in Experimental Example 6 was analyzed by various NMR, the results obtained in Experimental Example 5 were the same.

  With respect to the products of Experimental Examples 1-2 and 4 to 6 (LiTCB, EMImTCB), the decomposition start temperature and the water content were measured. The results are shown in Table 4.

[Pyrolysis start temperature]
10 mg of ionic compounds such as LiTCB and EMImTCB are put in an aluminum pan, heated at 10 ° C./min, and the temperature when reduced by 2% from the initial mass is measured using a differential thermothermal gravimetric simultaneous measurement apparatus (“EXSTAR6000 TG manufactured by Seiko Instruments Inc.). / DTA ").

Experimental Example 1-2 and Experimental Example 6 show results when the extraction step (iii) in which the blending ratio of the mixed solvent of the organic solvent and water was not performed.
From Table 4, by carrying out the extraction step (iii) with a mixed solvent of an organic solvent and water, the thermal decomposition temperature rises, and the heat resistance inherent to the ionic compounds (1) and (2) is fully exhibited. (Experimental examples 4 and 5). In Experimental Example 4, the moisture content was reduced with the improvement of heat resistance. This is because the impurities (impurities such as by-products) dissolved in the butyl acetate phase easily contain water in the extraction step (iii) of Experimental Example 4, and this impurity was separated from the ionic compound. It is thought that the water content was reduced.

Experimental example 7 LSV measurement About the electrolyte material (ionic compound) obtained by Experimental example 4-6, LSV measurement was performed like Experimental example 1-1. The measurement conditions are as follows.

Experimental Example 7-1
Using the electrolyte material obtained in Experimental Example 4, a sample solution was prepared in the same manner as in Experimental Example 1-1, and LSV measurement was performed under the following conditions. The results are shown in FIG.
Measurement conditions Working electrode: Glassy carbon electrode (manufactured by BAS, product number: 11-2411, electrode surface area 1 mmφ (0.785 mm ² ))
Reference electrode: Ag electrode (Ag / Ag ⁺ )
Counter electrode: Pt electrode Solvent: γ-butyrolactone Concentration: 0.7 mol / l
Sweep speed: 100 mV / sec
Sweep range: Natural potential to 10 V (vs. Ag / Ag ⁺ )

Experimental Example 7-2
Using the electrolyte materials obtained in Experimental Examples 5 and 6, sample solutions were prepared in the same manner as in Experimental Example 1-1, and each sample solution was subjected to LSV measurement under the following conditions. Since EMImTCB is a liquid at 25 ° C., no solvent was used in this experimental example, and EMImTCB was directly used for LSV measurement. The results are shown in FIG.
Measurement conditions Working electrode: Pt electrode (manufactured by BAS, product number: 002313, electrode surface area 1.6 mmφ (2.011 mm ² )) Reference electrode: Ag electrode (Ag / Ag ⁺ )
Counter electrode: Pt electrode Solvent: None Sweep speed: 100 mV / sec
Sweep range: Natural potential to 10 V (vs. Ag / Ag ⁺ )

  As shown in FIG. 3, the withstand voltage characteristic of the electrolyte material of Experimental Example 5 was better than that of Experimental Example 6. This is presumably because the impurity content was reduced by the extraction step (iii).

Experimental Example 7-3, Experimental Example 7-4
Experimental example using the ionic compound (LiTCB) obtained in Experimental Example 4, and commercially available LiBF ₄ (Kishida Chemical Co., Ltd., Li battery grade), LiPF ₆ (Kishida Chemical Co., Ltd., Li battery grade) Sample solutions were prepared in the same manner as in 1-1, and LSV measurement was performed on each sample solution under the following conditions. The result of Experimental Example 7-3 is shown in FIG. 4, and the result of Experimental Example 7-4 is shown in FIG.

Measurement conditions of Experimental Example 7-3 Working electrode: Pt electrode (manufactured by BAS, product number: 002313, electrode surface area 1.6 mmφ (2.011 mm ² ))
Reference electrode: Li electrode (Li / Li ⁺ )
Counter electrode: Pt electrode Solvent: γ-butyrolactone Concentration: 0.7 mol / l
Sweep range: natural potential to 10 V (vs. Li / Li ⁺ )
Sweep speed: 100 mV / sec

Measurement conditions of Experimental Example 7-4 Working electrode: Glassy carbon electrode (manufactured by BAS, product number: 11-2411, electrode surface area 1 mmφ (0.785 mm ² ))
Reference electrode: Ag electrode (Ag / Ag ⁺ )
Counter electrode: Pt electrode Solvent: γ-butyrolactone Concentration: 0.7 mol / l
Sweep range: Natural potential to 10 V (vs. Ag / Ag ⁺ )
Sweep speed: 100 mV / sec

Further, when the potential (referred to as oxidation potential) when a current of ² mA / cm ² flows is obtained from the result of Experimental Example 7-4, the oxidation potential of each electrolyte material is as shown in Table 5 below.

In this experiment, a voltage was applied in the range of 0 to 10 V (Ag / Ag ⁺ ). Therefore, when converted to the Li standard, a voltage was applied in the range of 3.8 to 13,8 V (Li / Li ⁺ ). It will be.

  According to the present invention, it is possible to provide electrolyte materials (i) and (ii) having reduced water content that adversely affect electrochemical characteristics, and methods for producing them. Therefore, it is considered that the electrolyte materials (i) and (ii) of the present invention having a reduced moisture content show good withstand voltage characteristics and are suitably used for various electrochemical devices.

Claims (3)

An electrolyte material manufacturing method comprising an ionic compound represented by the following general formula (1) and a medium, wherein the concentration of the ionic compound is 1% by mass or more and the water content is 50 ppm or less. Te, the following general formula ionic compound represented by (1) mixing ratio of the organic solvent and water to water and phase separation at a mass ratio of 20: 1 to 2: a step of extracting with a mixed solvent a And a step of extracting with a mixed solvent B in which the mixing ratio of the organic solvent to be phase-separated with water and water is 1: 2 to 1:20 by mass ratio.
_{^{Kt 1 m + [B - (}} CN) 4] m (1)
(In the formula, Kt ₁ represents an inorganic cation, and m represents an integer of 1 to 3.) A method for producing an electrolyte material represented by the following general formula (2), wherein the electrolyte material obtained by the production method according to claim 1 is reacted with a salt of an onium cation.
_{^{Kt 2 m + [B - (}} CN) 4] m (2)
(Wherein, Kt ₂ represents an onium cation, m represents the integer of 1 to 3.) After mixing the above following general formula (1) ionic compound represented by the lactone-based solvents and / or carbonate-based solvent, to claim 1 or 2 comprising contacting a process and / or molecular sieve perform distillation The manufacturing method of the electrolyte material of description .