JP2006216524A - Material for electrolytic solution - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a material for an electrolytic solution having improved ionic conductivity, showing excellent in low temperature property, and being stable with time. <P>SOLUTION: The material is one containing an ionic compound, and the material comprises a cyano group-containing anion as an essential component represented by general formula (1), (in the formula, X represents at least one element selected from a group comprising B, C, N, O, Al, Si, P, S, As, and Se. M<SP>1</SP>and M<SP>2</SP>are each identical or different and represents an organic coupling group. "a" is an integer of one or more, b, c, d, and e are an integer of 0 or more), and contains 1-99% by weight of a solvent in 100% by weight of the material. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an electrolyte material. More specifically, the present invention relates to an electrolytic solution material suitably used for an electrolytic solution that is an ionic conductor of an electrochemical device.

Electrolytic solution materials are widely used in various types of batteries using ion conduction. For example, in addition to batteries having charging and discharging mechanisms such as primary batteries, lithium (ion) secondary batteries and fuel cells, electrolysis It is used in electrochemical devices such as capacitors, electric double layer capacitors, solar cells, and electrochromic display elements. In these, a battery is generally composed of a pair of electrodes and an electrolytic solution which is an ionic conductor filling between the electrodes. Examples of such ionic conductors include organic solvents such as γ-butyrolactone, N, N-dimethylformamide, propylene carbonate, tetrahydrofuran, lithium perchlorate, LiPF ₆ , LiBF ₄ , tetraethylammonium borofluoride, tetramethyl phthalate. An electrolytic solution in which an electrolyte such as ammonium is dissolved is used. In such an ionic conductor, when the electrolyte is dissolved, it is dissociated into a cation and an anion to conduct ions in the electrolytic solution.

FIG. 1 shows a schematic cross-sectional view of one form of a general lithium (ion) secondary battery. Such a lithium (ion) secondary battery has a positive electrode and a negative electrode formed from an active substance, and an electrolyte solution composed of an organic solvent in which a lithium salt such as LiPF ₆ is dissolved as a solute, An ionic conductor is formed between the negative electrode. In this case, at the time of charging, a reaction of C ₆ Li → 6C + Li + e occurs in the negative electrode, and electrons (e) generated on the negative electrode surface are ion-conducted in the electrolytic solution and move to the positive electrode surface, and on the positive electrode surface, CoO ₂ + Li + e → A reaction of LiCoO ₂ occurs, and a current flows from the negative electrode to the positive electrode. When discharging, a reverse reaction occurs during charging, and current flows from the positive electrode to the negative electrode.

However, in the electrolytic solution constituting such an electrochemical device, the problem is that the organic solvent easily evaporates and the flash point is low, and the electrolytic solution is solidified at a low temperature, so that the performance as an electrolytic solution cannot be exhibited. Since there are problems, materials that can improve these problems have been demanded.

Then, examination which applies liquid room temperature molten salt at room temperature is performed (for example, refer nonpatent literature 1). Known as room temperature molten salts are complexes of aromatic quaternary ammonium halides such as N-butylpyridium and N-ethyl-N'-methyl-imidazolium with halogen aluminum, and mixtures of two or more lithium salts. (For example, see Non-Patent Document 2). However, the former complex has a problem of corrosivity due to halide ions, and the latter is a supercooled liquid which is thermodynamically unstable and solidifies with time.

On the other hand, imidazolium salts and pyridium salts such as tetrafluoroborate anion and bistrifluoromethanesulfonylimide anion are relatively stable electrically and have been actively studied in recent years. However, performance such as ionic conductivity is not sufficient, and since it contains fluorine, there is a problem such as electrode corrosion, and a material for constituting an ionic conductor that exhibits excellent basic performance. There was room for ingenuity.

In addition, the dicyanoamide salt of N-alkyl-N-methylpyrrolidinium or 1-alkyl-3-methylimidazolium was studied for thermal characteristics, viscosity, and qualitative potential stability. It is disclosed that it is useful as a low-viscosity ionic liquid (see, for example, Non-Patent Document 3). However, there is no disclosure regarding a technique for applying such a dicyanoamide salt to an ionic conductor material of an electrochemical device, and there is room for contrivance to make a material constituting an ionic conductor that exhibits excellent basic performance. there were.

For cyano-substituted salts, including cyano-substituted methides and amides, the group consisting of N-cyano-substituted amides, N-cyano-substituted sulfonamides, 1,1,1-dicyano-substituted sulfonyl methides and 1,1,1-dicyanoacyl methides An electrolyte containing at least one salt selected from the above and a matrix material is disclosed (for example, see Patent Document 1). In this electrolyte, a salt in the form of powder is prepared and dissolved in an organic solvent as a matrix material to form a liquid electrolyte or a solid polymer electrolyte. The present invention also relates to a solid conductive material containing an ionic dopant as a conductive species in an organic matrix. For example, N-methyl-N-propylpyrrolidinium dicyanoamide salt is used as an organic matrix and LiSO ₃ CF ₃ is used as an ionic dopant. (For example, refer to Patent Document 2). However, in these techniques, there is no disclosure regarding applying a compound in the form of a salt to a material of an electrolytic solution excellent as an ionic conductor of an electrochemical device and making the salt itself a liquid.

In addition, regarding an ionic compound including an anionic moiety bonded to the cationic moiety M ^{+ m} , M in the cationic moiety is hydroxonium, nitrosonium NO ⁺ , ammonium NH ₄ ⁺ , a metal cation having a valence m, a valence m Or an anionic moiety having one of the formulas R _D —Y—C (C≡N) ₂ ^— or Z—C (C≡N) ₂ ^—. It is disclosed that this ionic compound can be used for an ion conductive material or the like (see, for example, Patent Document 3). However, there has been room for contrivance to make a suitable material that constitutes an electrolytic solution that exhibits excellent basic performance.
Japanese translation of PCT publication No. 2002-523879 (pages 1-7, 30-43) WO 01/15258 pamphlet (pages 14-17) Japanese translation of PCT publication No. 2000-508677 (page 1-12) Koura et al. Electrochem. Soc. 1993, 140, p. 602 C. A. Angell et al., Nature, 1933, 362, p. 137 Douglas R.D. MacFarlane et al., Chem. Commun. 2001, p. 1430-1431

The present invention has been made in view of the above-described situation, and an object of the present invention is to provide an electrolytic solution material having improved ionic conductivity, excellent low temperature characteristics, and stable over time.

As a result of various studies on materials constituting the electrolyte solution which is an ionic conductor, the present inventors have reduced the volatility by using a salt form, so that the electrolyte can be dissolved in the molten salt. In view of the usefulness of the ionic conductor in the liquid state, if an anion having a specific structure is essential, the ionic conductivity is excellent. In particular, it has been found that improvement in the problem of solvent volatilization and improvement in ionic conductivity can be sufficiently achieved. Usually, if the content of the solvent in the electrolyte material is low, it may freeze at a low temperature of, for example, −55 ° C., and the ionic conductivity may not be measured. It can be reduced, and it can be excellent in ionic conductivity without freezing even at low temperature, and it can demonstrate excellent basic performance when used as an electrolyte, and it can solve the above problems brilliantly I came up with what I can do. In addition, when such a material does not have a fluorine atom, the corrosiveness to the electrode or the like can be suppressed due to this, and it can function stably over time, and constitutes an electrolytic solution. It has been found that it can function as a liquid material and can be suitable for electrochemical devices. Furthermore, by having a form having a cation having a specific structure, it becomes a room temperature molten salt that stably maintains a molten state at room temperature, can suppress volatilization to the outside at high temperature, and is an electrochemical device that can withstand a long period of time. The present invention has also been found to be more suitable as a material constituting the electrolyte solution.

That is, the present invention is an electrolytic solution material containing an ionic compound, and the electrolytic solution material has the following general formula (1);

(Wherein X represents at least one element selected from B, C, N, O, Al, Si, P, S, As and Se. M ¹ and M ² are the same or different, An organic linking group, Q represents an organic group, a is an integer of 1 or more, and b, c, d, and e are integers of 0 or more. The electrolyte solution material is characterized by containing 1 to 99% by mass of a solvent in 100% by mass of the electrolyte solution material.
The present invention is described in detail below.

The electrolyte material of the present invention comprises 1 to 99% by mass of a solvent in 100% by mass of the electrolyte material. If it is less than 1% by mass, the ionic conductivity will not be sufficiently improved, and if it exceeds 99% by mass, the stability will not be sufficiently improved due to volatilization of the solvent or the like. As a lower limit, Preferably, it is 1.5 mass%, More preferably, it is 20 mass%, More preferably, it is 50 mass%. As an upper limit, Preferably, it is 85 mass%, More preferably, it is 75 mass%, More preferably, it is 65 mass%. As a range, the solvent amount is preferably 50 to 85% by mass.
The electrolyte material of the present invention has reduced volatile matter, and does not freeze even at a low temperature of, for example, −55 ° C., and has excellent ionic conductivity. It can demonstrate its performance.

The solvent is not particularly limited as long as it can improve the ionic conductivity. For example, water, an organic solvent, or the like is preferable. Examples of the organic solvent include ethers such as 1,2-dimethoxyethane, tetotahydrofuran, 2-methyltetrahydrofuran, crown ether, triethylene glycol methyl ether, tetraethylene glycol dimethyl ether, dioxane; ethylene carbonate, propylene Carbonates such as carbonate, diethyl carbonate, methyl ethyl carbonate; chain carbonates such as dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, diphenyl carbonate, methyl phenyl carbonate; ethylene carbonate, propylene carbonate, 2,3-dimethyl ethylene carbonate Cyclic carbonates such as butylene carbonate, vinylene carbonate, 2-vinylethylene carbonate; methyl formate, methyl acetate, propionic acid, methyl propionate, ethyl acetate, propyl acetate, Aliphatic carboxylic acid esters such as methyl and amyl acetate; Aromatic carboxylic acid esters such as methyl benzoate and ethyl benzoate; Carboxylic acid esters such as γ-butyrolactone, γ-valerolactone and δ-valerolactone; Phosphate esters such as trimethyl acid, ethyldimethyl phosphate, diethylmethyl phosphate, triethyl phosphate; nitriles such as acetonitrile, propionitrile, methoxypropionitrile, glutaronitrile, adiponitrile, 2-methylglutaronitrile, etc. Amides such as N-methylformamide, N-ethylformamide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidinone, N-methylpyrrolidone, N-vinylpyrrolidone; dimethylsulfone, ethylmethylsulfone , Diethyls Sulfur compounds such as Hong, sulfolane, 3-methylsulfolane, 2,4 dimethylsulfolane: alcohols such as ethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, Ethers such as 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, 2,6-dimethyltetrahydrofuran, tetrahydropyran; sulfoxides such as dimethyl sulfoxide, methylethyl sulfoxide, diethyl sulfoxide; benzonitrile, Aromatic nitriles such as tolunitrile; nitromethane, 1,3-dimethyl-2-imidazolidinone, 1,3-dimethyl-3,4, Examples include 5,6-tetrahydro-2 (1H) -pyrimidinone, 3-methyl-2-oxazolidinone, and one or more of these are preferable. Among these, carbonate esters, aliphatic esters, and ethers are more preferable, carbonates are more preferable, and cyclic esters such as γ-butyrolactone and γ-valerolactone are most preferable.

The electrolyte material of the present invention contains an ionic compound. The electrolytic solution material can be suitably used as a medium (solvent) that is a material constituting the electrolytic solution of the electrochemical device and / or an electrolyte. Moreover, an ionic compound consists of a compound comprised by a cation and an anion, and can use 1 type (s) or 2 or more types. Such an ionic compound is preferably a liquid having a constant volume and fluidity at 40 ° C., and specifically, a liquid having a viscosity of 200 mPa · s or less at 40 ° C. is preferable. More preferred is a liquid of 100 mPa · s or less, and still more preferred is a liquid of 50 mPa · s or less.

The electrolyte solution material of the present invention essentially comprises an anion having a cyano group represented by the general formula (1). Such an anion may be an anion constituting an ionic compound contained in the electrolytic solution material of the present invention, or an anion constituting another compound. By setting it as such a form, it is excellent in ionic conductivity and can be made suitable for the material which comprises an ionic conductor. In addition, the electrolyte material may contain other anions as long as it functions suitably when used as an electrolyte, such as bistrifluoromethanesulfonylimide anion (TFSI), tetrafluoroborate. It may contain an anion, a monocarboxylic acid such as acetic acid or benzoic acid, a dicarboxylic acid anion such as phthalic acid, maleic acid or succinic acid anion, or a sulfate ester anion such as methyl sulfuric acid or ethyl sulfuric acid. Also, fluorine-containing inorganic ions such as fluorine-containing inorganic ions, hexafluorophosphate ions, hexafluoroarsenate ions, hexafluoroantimonate ions, hexafluoroniobate ions, hexafluorotantalate ions; hydrogen phthalate ions, maleic acid Carboxylic acid ions such as hydrogen ion, salicylic acid ion, benzoic acid ion and adipic acid ion; sulfonic acid such as benzenesulfonic acid ion, toluenesulfonic acid ion, dodecylbenzenesulfonic acid ion, trifluoromethanesulfonic acid ion, perfluorobutanesulfonic acid Inorganic oxo acid ions such as borate ion and phosphate ion; bis (trifluoromethanesulfonyl) imide ion, bis (pentafluoroethanesulfonyl) imide ion, tris (trifluoromethanesulfuric acid) Nyl) methide ion, perfluoroalkylfluoroborate ion, perfluoroalkylfluorophosphate ion, borodicatecholate, borodiglycolate, borodisalicylate, borotetrakis (trifluoroacetate), bis (oxalato) borate, etc. You may contain 1 type, or 2 or more types, such as a coordinate borate ion.

In the anion represented by the general formula (1), X represents at least one element selected from B, C, N, O, Al, Si, P, S, As, and Se. Or S is preferable. More preferably, it is C or N. More preferably, it is C, and the form in which X in the general formula (1) is a carbon element (C) is one of the preferred forms of the present invention. M ¹ and M ² are the same or different and each represents an organic linking group, each independently a linking group selected from —S—, —O—, —SO ₂ —, —CO—, preferably , _-SO 2 -, - is a CO-. Q is an organic group, a hydrogen atom, a halogen _{atom, C p F (2p + 1} -q) H q, OC p F (2p + 1-q) H q, SO 2 C p F (2p + 1-q) H q, _{CO 2 C p F (2p +} 1-q) H q, COC p F (2p + 1-q) H q, SO 3 C 6 F 5-r H r, NO 2 ( wherein, 1 ≦ p ≦ 6,0 <q ≦ 13, 0 <r ≦ 5) and the like are preferable. More preferably a fluorine atom, a chlorine _{atom, C p F (2p + 1} -q) H q, SO 2 C p F (2p + 1-q) H q. Further, a is an integer of 1 or more, and b, c, d, and e are integers of 0 or more, but a, d, and e are determined by the valence of the element X, for example, X When X is a sulfur atom, a = 1, d = 0, e = 0, and when X is a nitrogen atom, (1) a = 2, d = 0, e = 0, (2) a = 1, d = 1, e = 0, or (3) a = 1, d = 0, or e = 1. Also, b and c are preferably 0.
Examples of the anion represented by the general formula (1) include a dicyanoamide anion (DCA), a thiocyanate anion, a tricyanomethide anion (TCM), a tetracyanoboron anion, a cyanooxy anion (CYO), and the like that do not contain fluorine. In view of excellent corrosion resistance of electrodes and the like, tricyanomethide anion is particularly preferable.

Examples of the anion having a cyano group include the following general formula (2):

(Wherein X represents at least one element selected from B, C, N, O, Al, Si, P, S, As and Se. M ¹ and M ² are the same or different, Represents an organic linking group, a is an integer of 1 or more, and b, c, and d are integers of 0 or more.
In the anion represented by the general formula (2), X, M ¹ and M ² are the same as described above. a is an integer of 1 or more, and b, c, and d are integers of 0 or more, but a and d are determined by the valence of the element X. For example, when X is a sulfur atom, When a = 1 and d = 0, and X is a nitrogen atom, a = 2 and d = 0, or a = 1 and d = 1.
As the anion represented by the general formula (2), dicyanoamide anion (DCA), tricyanomethide anion (TCM) and the like are preferable because they do not contain fluorine and are excellent in corrosion resistance of electrodes and the like. Chidoanions are preferred.

Regarding the amount of anion in the electrolytic solution material of the present invention, the lower limit value of the content of the compound that is derived from the anion is preferably 1% by mass with respect to 100% by mass of the electrolytic solution material. More preferably, it is 5 mass%, More preferably, it is 10 mass%. As an upper limit, 99.5 mass% is preferable. More preferably, it is 95 mass%, More preferably, it is 90 mass%.

The electrolyte solution material of the present invention contains cations constituting the ionic compound, but may contain other cations. The cation to be contained in the electrolytic solution material of the present invention is not particularly limited as long as it functions suitably when used as an electrolytic solution. For example, the following general formula (3);

(In the formula, L represents C, Si, N, P, S, or O. R is the same or different, and is an organic group, which may be bonded to each other. S is 3, 4, or 5) And is a value determined by the valence of the element L.).

Examples of the onium cation represented by the general formula (3) include the following general formula:

(In formula, R is the same as that of General formula (3).) What is represented is preferable.
Among these, the following onium cations are preferable.
(I) the following general formula;

10 heterocyclic onium cations represented by
(II) the following general formula;

5 types of unsaturated onium cations represented by
(III) the following general formula;

9 kinds of saturated ring onium cations represented by
In said general formula, R < ¹ > -R < ¹² > is the same or different, is an organic group, and may mutually be couple | bonded.
(IV) R is an alkyl group of _C 1 -C ₈ chain onium cations.
Among such onium cations, more preferably, L in the general formula (3) is a nitrogen atom, and more preferably the following general formula:

(Wherein R ^{1 to} R ¹² are the same as above), triethylmethylammonium, dimethylethylpropylammonium, diethylmethylmethoxyethylammonium, trimethylpropylammonium, trimethylbutyl And chain onium cations such as ammonium and trimethylhexylammonium.
Examples of the organic group of R ^{1 to} R ¹² include a hydrogen atom, a fluorine atom, an amino group, an imino group, an amide group, an ether group, an ester group, a hydroxyl group, a carboxyl group, a carbamoyl group, a cyano group, a sulfone group, and a sulfide group. Or a straight-chain, branched-chain or cyclic hydrocarbon group having 1 to 18 carbon atoms which may contain a nitrogen atom, an oxygen atom, a sulfur atom, or the like, more preferably a hydrogen atom or a fluorine atom. , A cyano group, a sulfone group, a hydrocarbon group having 1 to 8 carbon atoms, and a fluorocarbon group.
A compound composed of such an onium cation and the anion as described above becomes a room temperature molten salt that stably maintains a molten state at room temperature, and the electrolyte material of the present invention containing such a molten salt is long. It becomes suitable as a material of an ionic conductor of an electrochemical device that can withstand a period. In addition, molten salt is what can maintain a liquid state stably in the temperature range of room temperature to 80 degreeC.

In the electrolyte material of the present invention, it is preferable that a nitrogen heterocyclic cation having a conjugated double bond is essential. Examples of the nitrogen heterocyclic cation having such a conjugated double bond include 10 types of heterocyclic onium cations represented by the above general formula (I) and 5 types of unsaturated onium represented by the above general formula (II). Among the cations and the like, those having a conjugated double bond and L in the general formula (3) being a nitrogen atom are suitable.
As the abundance of the cation in the electrolytic solution material of the present invention, the lower limit is preferably 0.5 mol with respect to 1 mol of the anion present in the electrolytic solution material. More preferably, it is 0.8 mol. The upper limit is preferably 2.0 mol. More preferably, it is 1.2 mol.

The electrolyte material of the present invention preferably further comprises an alkali metal salt and / or an alkaline earth metal salt. The electrolytic solution material of the present invention containing such an alkali metal salt and / or alkaline earth metal salt contains an electrolyte and is suitable as a material for an electrolytic solution of an electrochemical device. 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 preferably, it is a lithium salt.

The alkali metal salt and / or alkaline earth metal salt may be a compound that requires an anion as described above, or other compounds. The electrolyte salt is preferably an electrolyte salt having a large dissociation constant in the electrolytic solution. For example, alkali metal salts or alkaline earths of trifluoromethanesulfonic acid such as LiCF ₃ SO ₃ , NaCF ₃ SO ₃ , KCF ₃ SO _3, etc. Metal salt; Alkali metal salt or alkaline earth metal salt of perfluoroalkanesulfonic acid imide such as LiN (CF ₃ SO ₃ ) ₃ , LiN (CF ₃ CF ₃ SO ₂ ) ₂ ; LiPF ₆ , NaPF ₆ , KPF _6, etc. Hexafluorophosphoric acid alkali metal salts and alkaline earth metal salts; LiClO ₄ , NaClO _{4 and} other perchloric acid alkali metal salts and alkaline earth metal salts; LiBF ₄ and NaBF _{4 and} other tetrafluoroborate salts; LiAsF ₆ , Alkali metal salts such as LiI, NaI, NaAsF ₆ and KI are preferred. Among these, from the viewpoint of solubility and ionic conductivity, LiPF ₆ , LiBF ₄ , LiAsF ₆ , and alkali metal salts or alkaline earth metal salts of perfluoroalkanesulfonic acid imide are preferable.

The electrolyte material may contain other electrolyte salts, such as quaternary ammonium salts of perchloric acid such as tetraethylammonium perchlorate; tetrafluoroboric acid such as (C ₂ H ₅ ) ₄ NBF _4. A quaternary ammonium salt such as a quaternary ammonium salt or (C ₂ H ₅ ) ₄ NPF ₆ ; a quaternary phosphonium salt such as (CH ₃ ) ₄ P · BF ₄ or (C ₂ H ₅ ) ₄ P · BF ₄ is preferred. In view of solubility and ionic conductivity, quaternary ammonium salts are preferred.

The amount of the electrolyte salt in the electrolytic solution material of the present invention is preferably 0.1% by mass or more and more preferably 50% by mass or less with respect to 100% by mass of the electrolytic solution material. If it is less than 0.1% by mass, the absolute amount of ions may be insufficient and the ionic conductivity may be reduced. If it exceeds 50% by mass, the movement of ions may be greatly inhibited. More preferably, it is 30 mass% or less.

The electrolyte solution material of the present invention can also be suitably used as a material for an ion conductor constituting a hydrogen battery by containing protons. Such an electrolyte material further comprising protons is one of the preferred embodiments of the present invention. In the present invention, the inclusion of a compound that can dissociate to generate a proton causes the proton to be present in the electrolytic solution.

The abundance of protons in the electrolyte material of the present invention is preferably 0.01 mol / L or more, more preferably 10 mol / L or less, with respect to the electrolyte material. If it is less than 0.01 mol / L, the absolute amount of protons may be insufficient and proton conductivity may be reduced. When it exceeds 10 mol / L, there is a possibility that proton transfer is greatly inhibited. More preferably, it is 5 mol / L or less.

The electrolyte material of the present invention may contain one or more components other than those described above as long as the effects of the present invention are exhibited. For example, the electrolyte material may contain various inorganic oxide fine particles.
As the inorganic oxide fine particles, those having non-electron conductivity and electrochemical stability are preferable, and those having ion conductivity are more preferable. As such fine particles, ion conductive or nonconductive ceramic fine particles such as α, β, γ-alumina, silica, titania, zirconia, magnesia, barium titanate, titanium oxide, and hydrotalcite are suitable.

The specific surface area of the inorganic oxide fine particles is preferably as large as possible, preferably 5 m ² / g or more, more preferably 50 m ² / g or more by the BET method. The crystal particle size of such inorganic oxide fine particles may be mixed with other components in the electrolytic solution, but the size (average crystal particle size) is preferably 0.01 μm or more, and more preferably 20 μm or less. More preferably, it is 0.01 μm or more and 2 μm or less.
As the shape of the inorganic oxide fine particles, various shapes such as a spherical shape, an oval shape, a cubic shape, a rectangular parallelepiped shape, a cylindrical shape, and a rod shape can be used.
The amount of the inorganic oxide fine particles added is preferably 100% by mass or less with respect to the electrolyte material. If it exceeds 100% by mass, the ion conductivity may be reduced. More preferably, it is 0.1% by mass or more and 20% by mass or less.
In addition, acid anhydrides such as acetic anhydride, phthalic anhydride, maleic anhydride, succinic anhydride, pyromellitic anhydride, acid compounds thereof, and basic compounds such as triethylamine and methylimidazole may be added. As an addition amount, it is preferable that it is 50 mass% or less with respect to electrolyte solution material. More preferably, it is 0.01 mass% or more and 20 mass% or less.

The electrolyte material of the present invention may also contain various additives in addition to the salt and solvent described above. The purpose of adding the additive is various, and includes improvement of electrical conductivity, improvement of thermal stability, suppression of electrode deterioration due to hydration and dissolution, suppression of gas generation, improvement of withstand voltage, improvement of wettability, etc. it can. Examples of such additives include nitro compounds such as p-nitrophenol, m-nitroacetophenone, and p-nitrobenzoic acid, dibutyl phosphate, monobutyl phosphate, dioctyl phosphate, monooctyl phosphonate, monophosphate Boron compounds such as phosphorus compounds such as boric acid or boric acid and polyhydric alcohols (ethylene glycol, glycerin, mannitol, polyvinyl alcohol, etc.) and polysaccharides, nitroso compounds, urea compounds, arsenic compounds, titanium compounds, Silicic acid compounds, aluminate compounds, nitric acid and nitrous acid compounds, 2-hydroxy-N-methylbenzoic acid, benzoic acids such as di (tri) hydroxybenzoic acid, gluconic acid, dichromic acid, sorbic acid, dicarboxylic acid, EDTA , Fluorocarboxylic acid, picric acid, suberic acid, adipine , Sebacic acid, heteropolyacid (tungstic acid, molybdic acid), gentisic acid, borodigentisic acid, salicylic acid, N-aminosalicylic acid, borodiprotocatechuic acid, borodipyrocatechol, bamonic acid, boric acid, borodiresorcylic acid, resorcylic acid, Borodiprotocaquelic acid, glutaric acid, acids such as dithiocarbamic acid, esters thereof, amides and salts thereof, silane coupling agents, silicon compounds such as silica and aminosilicate, amine compounds such as triethylamine and hexamethylenetetramine, L- Amino acids, benzoles, polyphenols, 8-oxyquinoline, hydroquinone, N-methylpyrocatechol, quinoline and thioanisole, thiocresol, thiobenzoic acid and other sulfur compounds, sorbitol, L-histidine, etc. It may be used or two or more.
Although content of the said additive is not specifically limited, For example, it is preferable that it is the range of 0.1-20 mass% with respect to 100 mass% of electrolyte material. More preferably, it is the range of 0.5-10 mass%.

The ionic conductivity of the electrolyte material of the present invention is preferably 1 × 10 ⁻⁷ S / cm or more at −55 ° C. If it is less than 1 × 10 ⁻⁷ S / cm, the electrolytic solution using the electrolytic solution material of the present invention may not be sufficiently capable of functioning stably over time while maintaining excellent ionic conductivity. There is. More preferably, it is 1 × 10 ⁻⁶ S / cm or more, further preferably 5 × 10 ⁻⁵ S / cm or more, and particularly preferably 1 × 10 ⁻⁴ S / cm or more.
The ion conductivity is measured by, for example, a complex impedance method using an impedance analyzer HP4294A (trade name, manufactured by Toyo Technica) using a SUS electrode or an impedance analyzer SI1260 (trade name, manufactured by Solartron). Is preferred.

The electrolyte material preferably has a viscosity at 25 ° C. of 300 mPa · s or less. If it exceeds 300 mPa · s, the ionic conductivity may not be sufficiently improved. More preferably, it is 200 mPa * s or less, More preferably, it is 100 mPa * s or less, Most preferably, it is 50 mPa * s or less.
The method for measuring the viscosity is not particularly limited, but a method of measuring at 25 ° C. using a TV-20 viscometer cone plate type (manufactured by Tokimec) is preferable.

The electrolyte material preferably has a peak reduction rate of 50% or less after heating at 150 ° C. for 50 hours. By adopting such a form, it is possible to maintain characteristics such as high electrical conductivity, thermal stability, and withstand voltage characteristics that the electrolyte has at an initial stage for a long period of time, and sufficient long-term stability of the electrolyte Can be improved. The peak reduction rate is more preferably 30% or less, still more preferably 20% or less. Here, the peak indicates the peak area, and the peak reduction rate after heating at 150 ° C. for 50 hours is the peak of the ionic compound in the electrolyte material before heating at A, and after heating at 150 ° C. for 50 hours. When the peak is B, it is a value obtained by (A−B) / A × 100, and the peak can be obtained by liquid chromatography (LC) analysis.
In the present invention, the ionic compound itself contained in the electrolyte material may satisfy such a numerical range. That is, an ionic compound having a peak reduction rate of 50% or less after heating at 150 ° C. for 50 hours is also one aspect of the present invention.

The electrolyte material of the present invention is a primary battery, a battery having a charging / discharging mechanism such as a lithium (ion) secondary battery or a fuel cell, an electrolytic capacitor, an electric double layer capacitor, an electrochemical cell such as a solar cell or an electrochromic display element. It is suitable as a material for an ionic conductor constituting the device. A lithium secondary battery, an electrolytic capacitor or an electric double layer capacitor using such an electrolyte material of the present invention is also one aspect of the present invention.

When an electrochemical device is constituted using the electrolytic solution material of the present invention, as a preferable form of the electrochemical device, the basic component includes an ionic conductor, a negative electrode, a positive electrode, a current collector, a separator, and a container. is there.

As the ionic conductor, a mixture of an electrolyte and an organic solvent is suitable. If an organic solvent is used, this ionic conductor is generally called an electrolytic solution. The electrolytic solution material of the present invention can be suitably applied as an alternative to the electrolyte or organic solvent in the electrolytic solution in such an ionic conductor, and the electrolytic solution material of the present invention is used as a material for the ionic conductor. In an electrochemical device, at least one of these is constituted by the electrolyte material of the present invention. Among these, it is preferable to use as an alternative of the organic solvent in electrolyte solution.

The organic solvent may be an aprotic solvent that can dissolve the electrolytic solution material of the present invention, and the same organic solvents as described above are suitable. However, when two or more kinds of mixed solvents are used, when the electrolyte contains Li ions, among these organic solvents, an aprotic solvent having a dielectric constant of 20 or more and an aprotic solvent having a dielectric constant of 10 or less are used. It is preferable to prepare an electrolytic solution by dissolving in a mixed solvent. In particular, when a lithium salt is used, the solubility in an aprotic solvent having a dielectric constant of 10 or less, such as diethyl ether or dimethyl carbonate, is low, and sufficient ionic conductivity cannot be obtained by itself. Although the aprotic solvent alone has high solubility but high viscosity, ions are difficult to move and sufficient ionic conductivity cannot be obtained. If these are mixed, appropriate solubility and mobility can be ensured, and sufficient ionic conductivity can be obtained.

The electrolyte concentration in the ion conductor is preferably 0.01 mol / dm ³ or more, and more preferably a saturation concentration or less. If it is less than 0.01 mol / dm ³ , the ionic conductivity is low, which is not preferable. More preferably, 0.1 mol / dm ³ or more, is 1.5 mol / dm ³ or less.

In the case of a lithium battery, the negative electrode material is preferably lithium metal or an alloy of lithium and another metal. In the case of a lithium ion battery, a material using a phenomenon called intercalation of carbon, natural graphite, metal oxide, or the like obtained by firing a polymer, an organic substance, pitch, or the like is preferable. In the case of the electric double layer capacitor, activated carbon, porous metal oxide, porous metal, and conductive polymer are suitable.

As the positive electrode material, in the case of lithium batteries and lithium ion batteries, lithium-containing oxides such as LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ ; oxides such as TiO ₂ , V ₂ O ₅ , MoO ₃ ; Sulfides such as TiS ₂ and FeS; conductive polymers such as polyacetylene, polyparaphenylene, polyaniline, and polypyrrole are suitable. In the case of the electric double layer capacitor, activated carbon, porous metal oxide, porous metal, and conductive polymer are suitable.

Hereinafter, (1) a lithium secondary battery, (2) an electrolytic capacitor, and (3) an electric double layer capacitor using the electrolytic solution material of the present invention will be described in more detail.
(1) Lithium secondary battery A lithium secondary battery is composed of a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an ionic conductor using the electrolyte material of the present invention as basic constituent elements. It is. In this case, the electrolyte material of the present invention contains a lithium salt as an electrolyte. Such a lithium secondary battery is preferably a non-aqueous electrolyte lithium secondary battery that is a lithium secondary battery other than the water electrolyte. A schematic cross-sectional view of one embodiment of a lithium secondary battery is shown in FIG. This lithium secondary battery uses coke as a negative electrode active material, which will be described later, and uses a compound containing Co as the positive electrode active material. The reaction of ₆ Li → 6C + Li + e occurs, and the electron (e) generated on the negative electrode surface is ion-conductive in the electrolyte and moves to the positive electrode surface. On the positive electrode surface, the reaction of CoO ₂ + Li + e → LiCoO ₂ occurs. Current flows from the positive electrode to the positive electrode. When discharging, a reverse reaction occurs during charging, and current flows from the positive electrode to the negative electrode. Thus, electricity is stored or supplied by a chemical reaction by ions.

The negative electrode is preferably prepared by applying a negative electrode mixture containing a negative electrode active material, a negative electrode conductive agent, a negative electrode binder, and the like to the surface of the negative electrode current collector. The negative electrode mixture may contain various additives in addition to the conductive agent and the binder.
As the negative electrode active material, metallic lithium, a material capable of inserting and extracting lithium ions, and the like are suitable. Suitable materials that can occlude and release lithium ions include metallic lithium; pyrolytic carbon; coke such as pitch coke, needle coke, and petroleum coke; graphite; glassy carbon; phenol resin, furan resin, and the like. Organic polymer compound fired body fired at temperature and carbonized; carbon fiber; carbon material such as activated carbon; polymer such as polyacetylene, polypyrrole, polyacene; Li _4/3 Ti _5/3 O ₄ , TiS ₂ etc. Lithium-containing transition metal oxides or transition metal sulfides; metals such as Al, Pb, Sn, Bi, and Si that are alloyed with alkali metals; AlSb, Mg ₂ Si, in which alkali metals can be inserted between lattices, and cubic intermetallic compounds of NiSi _{2, etc., Li 3-f G f N} : lithium nitrogen compounds in (G transition metals), etc. Etc. are preferred. These can use 1 type (s) or 2 or more types. Among these, metallic lithium and carbon materials that can occlude / release alkali metal ions are more preferable.

The negative electrode conductive agent may be an electronic conductive material, such as natural graphite such as flake graphite, graphite such as artificial graphite; acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black, etc. Carbon black; conductive fibers such as carbon fibers and metal fibers; metal powders such as carbon fluoride, copper and nickel; organic conductive materials such as polyphenylene derivatives are suitable. These can use 1 type (s) or 2 or more types. Among these, artificial graphite, acetylene black, and carbon fiber are more preferable. The amount of the negative electrode conductive agent used is preferably 1 to 50 parts by weight, and more preferably 1 to 30 parts by weight with respect to 100 parts by weight of the negative electrode active material. Further, since the negative electrode active material has electronic conductivity, a negative electrode conductive agent need not be used.

The binder for the negative electrode may be either a thermoplastic resin or a thermosetting resin. Polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, styrene butadiene rubber, tetrafluoroethylene-hexafluoropropylene Polymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer, polychlorotri Fluoroethylene, vinylidene fluoride-pentafluoropropylene copolymer, propylene-tetrafluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene -Tetrafluoroethylene copolymer, vinylidene fluoride-perfluoromethyl vinyl ether-tetrafluoroethylene copolymer, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, An ethylene-methyl methacrylate copolymer, polyamide, polyurethane, polyimide, polyvinyl pyrrolidone, and a copolymer thereof are preferable. These can use 1 type (s) or 2 or more types. Among these, styrene butadiene rubber, polyvinylidene fluoride, ethylene-acrylic acid copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, polyamide, polyurethane, More preferred are polyimide, polyvinylpyrrolidone and copolymers thereof.

The current collector for the negative electrode may be an electronic conductor that does not cause a chemical change inside the battery. Stainless steel, nickel, copper, titanium, carbon, conductive resin, carbon on the surface of copper or stainless steel, Those having nickel or titanium adhered or coated thereon are suitable. Among these, copper and alloys containing copper are more preferable. These can use 1 type (s) or 2 or more types. Further, the surface of the negative electrode current collector can be oxidized and used. Furthermore, it is desirable to make the current collector surface uneven. As the shape of the current collector for the negative electrode, a foil, a film, a sheet, a net, a punched one, a lath body, a porous body, a foamed body, a molded body of a fiber group, and the like are suitable. The thickness of the current collector is preferably 1 to 500 μm.

The positive electrode is preferably prepared by coating a positive electrode mixture containing a positive electrode active material, a positive electrode conductive agent, a positive electrode binder, and the like on the surface of the positive electrode current collector. The positive electrode mixture may contain various additives in addition to the conductive agent and the binder.
Examples of the positive electrode active material include metal Li, Li _x CoO ₂ , Li _x NiO ₂ , Li _x MnO ₂ , Li _x Co _y Ni _1-y O ₂ , Li _x Co _y J _1-y O _z , and Li _x Ni. _{1-y J y O z,} Li x Mn 2 O 4, Li x Mn 2-y J y O 4; MnO 2, V g O h, Cr g O h (g and h is an integer of 1 or more) such as An oxide containing no lithium is suitable. These can use 1 type (s) or 2 or more types.
J represents at least one element selected from Na, Mg, Sc, Y, Mn, Fe, Co, Ni, Cu, Zn, Al, Cr, Pb, Sb, and B. X is 0 ≦ x ≦ 1.2, y is 0 ≦ y ≦ 0.9, z is 2.0 ≦ z ≦ 2.3, and x is charge / discharge of the battery. Will increase or decrease. Further, as the positive electrode active material, a transition metal chalcogenide, vanadium oxide or niobium oxide which may contain lithium, an organic conductive material composed of a conjugated polymer, a chevrel phase compound, or the like may be used. The average particle diameter of the positive electrode active material particles is preferably 1 to 30 μm.

The positive electrode conductive agent may be any electron conductive material that does not cause a chemical change in the charge / discharge potential of the positive electrode active material used, and is the same as the negative electrode conductive agent described above; metal powder such as aluminum and silver Conductive whiskers such as zinc oxide and potassium titanate; conductive metal oxides such as titanium oxide are suitable. These can use 1 type (s) or 2 or more types. Among these, artificial graphite, acetylene black, and nickel powder are more preferable. The amount of the positive electrode conductive agent used is preferably 1 to 50 parts by weight, and more preferably 1 to 30 parts by weight with respect to 100 parts by weight of the positive electrode active material. When carbon black or graphite is used, the amount is preferably 2 to 15 parts by weight with respect to 100 parts by weight of the positive electrode active material.

The positive electrode binder may be either a thermoplastic resin or a thermosetting resin, other than the styrene butadiene rubber in the negative electrode binder described above, and tetrafluoroethylene-hexafluoroethylene copolymer. A coalescence or the like is preferred. These can use 1 type (s) or 2 or more types. Among these, polyvinylidene fluoride and polytetrafluoroethylene are more preferable.

The positive electrode current collector may be any electron conductor that does not cause a chemical change in the charge / discharge potential of the positive electrode active material to be used. The surface of stainless steel, aluminum, titanium, carbon, conductive resin, aluminum or stainless steel Those having carbon or titanium adhered or coated thereon are suitable. These can use 1 type (s) or 2 or more types. Among these, aluminum or an alloy containing aluminum is preferable. Further, the surface of the positive electrode current collector can be oxidized and used. Furthermore, it is desirable to make the current collector surface uneven. The shape and thickness of the positive electrode current collector are the same as those of the negative electrode current collector described above.

The separator is preferably an insulating microporous thin film having a large ion permeability and a predetermined mechanical strength, and has a function of closing the pores at a certain temperature or higher and increasing the resistance. preferable. Materials include porous synthetic resin films of polyolefin polymers such as polyethylene and polypropylene, woven or non-woven fabrics made of organic materials such as polypropylene and fluorinated polyolefins, glass fibers, and inorganic materials from the viewpoint of organic solvent resistance and hydrophobicity. A woven fabric or a non-woven fabric is preferably used. The pore diameter of the pores of the separator is preferably in a range in which the positive electrode active material, the negative electrode active material, the binder, and the conductive agent detached from the electrode do not pass through, and is preferably 0.01 to 1 μm. As a thickness of a separator, it is preferable that it is 5-300 micrometers, More preferably, it is 10-50 micrometers. Moreover, as a porosity, it is preferable that it is 30 to 80%.
Moreover, it is preferable that the surface of the separator is modified in advance so as to reduce its hydrophobicity by a corona discharge treatment, a plasma discharge treatment, or other wet treatment using a surfactant. As a result, the wettability of the separator surface and the inside of the pores is improved, and the increase in the internal resistance of the battery can be suppressed as much as possible.

As the lithium secondary battery, a positive electrode mixture or a negative electrode mixture containing a gel holding an electrolyte solution in a polymer material, or a porous separator made of a polymer material holding an electrolyte solution is used as a positive electrode or a negative electrode. You may be comprised by integrating. The polymer material is not particularly limited as long as it can hold an electrolytic solution, and a copolymer of vinylidene fluoride and hexafluoropropylene is preferable.
Examples of the shape of the lithium secondary battery include a coin shape, a button shape, a sheet shape, a laminated shape, a cylindrical shape, a flat shape, a square shape, and a large size used for an electric vehicle.

(2) Electrolytic Capacitor An electrolytic capacitor is composed of an anode foil, a cathode foil, an electrolytic paper that is a separator sandwiched between the anode foil and the cathode foil, and a capacitor element composed of a lead wire and the electrolytic solution material of the present invention. The ion conductor used, a bottomed cylindrical outer case, and a sealing body for sealing the outer case are configured as basic components. A perspective view of one embodiment of the capacitor element is shown in FIG. The electrolytic capacitor in the present invention is obtained by impregnating a capacitor element with an electrolytic solution that is an ionic conductor using the electrolytic solution material of the present invention, and housing the capacitor element in a bottomed cylindrical outer case, It is possible to obtain the sealing member by attaching a sealing body to the portion and sealing the outer case by drawing the end portion of the outer case. As such an electrolytic capacitor, an aluminum electrolytic capacitor, a tantalum electrolytic capacitor, and a niobium electrolytic capacitor are suitable. A schematic cross-sectional view of one embodiment of the aluminum electrolytic capacitor is shown in FIG.

As the anode foil, an aluminum foil having a purity of 99% or more is chemically or electrochemically etched in an acidic solution and subjected to a surface expansion treatment, and then in an aqueous solution such as ammonium borate, ammonium phosphate, or ammonium adipate. A material obtained by performing a chemical conversion treatment and forming an anodized film layer on the surface thereof can be used.
The cathode foil is selected from one or more metal nitrides selected from titanium nitride, zirconium nitride, tantalum nitride and niobium nitride, and / or titanium, zirconium, tantalum and niobium on part or all of the surface. An aluminum foil formed with a film composed of one or more metals can be used.
Examples of the method for forming the film include a vapor deposition method, a plating method, a coating method, and the like. As a portion for forming the film, the entire surface of the cathode foil may be coated, or if necessary, For example, only one surface of the cathode foil may be coated with metal nitride or metal.

The lead wire is preferably composed of a connection part in contact with the anode foil and the cathode foil, a round bar part, and an external connection part. The lead wires are electrically connected to the anode foil and the cathode foil by means such as stitching and ultrasonic welding at the connection portions. Further, the connecting portion and the round bar portion in the lead wire are preferably made of high-purity aluminum, and the external connecting portion is preferably made of a copper-plated steel wire subjected to solder plating. In addition, an aluminum oxide layer formed by anodizing with an aqueous ammonium borate solution, an aqueous ammonium phosphate solution, or an aqueous ammonium adipate solution may be formed on part or all of the surface of the connecting portion with the cathode foil and the round bar portion. An insulating layer such as a ceramic coating layer made of Al ₂ O ₃ , SiO ₂ , ZrO ₂ or the like can be formed.

The exterior case is preferably made of aluminum.
The sealing body is preferably provided with a through hole through which each lead wire is led out, and is preferably composed of an elastic rubber such as butyl rubber, and the butyl rubber is, for example, a copolymer of isobutylene and isoprene. After adding and kneading a reinforcing rubber (carbon black, etc.), a bulking agent (clay, talc, calcium carbonate, etc.), a processing aid (stearic acid, zinc oxide, etc.), a vulcanizing agent, etc. A molded rubber elastic body can be used. Examples of vulcanizing agents include alkylphenol formalin resins; peroxides (dicumyl peroxide, 1,1-di- (t-butylperoxy) -3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5- Di- (t-butylperoxy) hexane etc.); quinoids (p-quinone dioxime, p, p'-dibenzoylquinone dioxime etc.); sulfur etc. can be used. Note that it is more preferable to coat the surface of the sealing body with a resin such as Teflon (registered trademark) or to attach a plate such as bakelite because the permeability of the solvent vapor is reduced.
As the separator, paper such as manila paper or kraft paper is usually used, but non-woven fabrics such as glass fiber, polypropylene and polyethylene can also be used.

The electrolytic capacitor may have a hermetic seal structure or a structure sealed in a resin case (for example, described in JP-A-8-148384). In the case of an aluminum electrolytic capacitor with a rubber seal, gas permeates through rubber to some extent, so that the solvent evaporates from the inside of the capacitor to the atmosphere in a high temperature environment, and from the atmosphere to the inside of the capacitor in a high temperature and high humidity environment. Moisture may be mixed into the capacitor, and under these harsh environments, the capacitor may cause undesirable characteristic changes such as a decrease in capacitance. On the other hand, a capacitor with a hermetic seal structure or a structure sealed in a resin case has a very small amount of gas permeation, and thus exhibits stable characteristics even in such a harsh environment.

(3) Electric Double Layer Capacitor An electric double layer capacitor is composed of a negative electrode, a positive electrode and an ion conductor using the electrolytic solution material of the present invention as basic constituent elements. An electrode element composed of a positive electrode and a negative electrode is made to contain an electrolytic solution that is an ionic conductor. FIG. 3 shows a schematic cross-sectional view of one embodiment of such an electric double layer capacitor and an enlarged schematic view of the electrode surface.

The positive electrode and the negative electrode are polarizable electrodes, and are composed of activated carbon fibers, activated carbon particle molded bodies, activated carbon particles such as activated carbon particles, a conductive agent, and a binder material as an electrode active material. It is preferable to use it as a plate-shaped molded body. In the electric double layer capacitor having such a configuration, as shown in the enlarged view of FIG. 3, the electric double layer generated at the interface between the polarizable electrode and the electrolytic solution due to physical adsorption / desorption of ions is charged. Will be stored.

As the activated carbon, those having an average pore diameter of 2.5 nm or less are preferable. The average pore diameter of the activated carbon is preferably measured by the BET method using nitrogen adsorption. The specific surface area of the activated carbon varies depending on the capacitance per unit area (F / m ² ) depending on the carbonaceous species, the decrease in bulk density accompanying the increase in the specific surface area, etc., but the specific surface area determined by the BET method by nitrogen adsorption as is preferably ^{500~2500m 2 / g, 1000~2000m 2 /} g is more preferable.

As the method for producing the activated carbon, plant-based wood, sawdust, coconut husk, pulp waste liquid, fossil fuel-based coal, heavy petroleum oil, or pyrolyzed coal and petroleum-based pitch, petroleum coke, Carbon aerogel, mesophase carbon, tar pitched fiber, synthetic polymer, phenol resin, furan resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyimide resin, polyamide resin, ion exchange resin, liquid crystal polymer, plastic disposal It is preferable to use an activation method in which a raw material such as a product or a waste tire is carbonized and then activated.

The activation method includes (1) a gas activation method in which a carbonized raw material is contact-reacted with water vapor, carbon dioxide gas, oxygen, and other oxidizing gas at a high temperature, and (2) zinc chloride and phosphoric acid are added to the carbonized raw material. An inert gas atmosphere that is uniformly impregnated with sodium phosphate, calcium chloride, potassium sulfide, potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, sodium sulfate, potassium sulfate, calcium carbonate, boric acid, nitric acid, etc. The chemical activation method which heats in and obtains activated carbon by the dehydration and oxidation reaction of a chemical | medical agent is mentioned, Any may be used.

Activated carbon obtained by the above activation method is preferably heat treated at 500 to 2500 ° C., more preferably 700 to 1500 ° C. in an inert gas atmosphere such as nitrogen, argon, helium, xenon, etc. The electron conductivity may be increased by removing functional groups or by developing carbon crystallinity. Examples of the shape of the activated carbon include crushing, granulation, granule, fiber, felt, woven fabric, and sheet shape. In the case of particles, the average particle diameter is preferably 30 μm or less in terms of improving the bulk density of the electrode and reducing the internal resistance.
As the electrode active material, in addition to activated carbon, a carbon material having the above-described high specific surface area may be used. For example, carbon nanotubes or diamond produced by plasma CVD may be used.

As the conductive agent, carbon black such as acetylene black and ketjen black, natural graphite, thermally expanded graphite, carbon fiber, metal fiber such as ruthenium oxide, titanium oxide, aluminum, and nickel are preferable. These can use 1 type (s) or 2 or more types. Among these, acetylene black and ketjen black are more preferable in that the conductivity is effectively improved with a small amount. The blending amount of the conductive agent varies depending on the bulk density of the activated carbon, but when the activated carbon is 100% by mass, 5 to 50% by mass is preferable, and 10 to 30% by mass is more preferable.

As the binder material, polytetrafluoroethylene, polyvinylidene fluoride, carboxymethyl cellulose, fluoroolefin copolymer crosslinked polymer, polyvinyl alcohol, polyacrylic acid, polyimide, petroleum pitch, coal pitch, phenol resin, and the like are suitable. These can use 1 type (s) or 2 or more types. The blending amount of the binder substance varies depending on the type and shape of the activated carbon, but when the activated carbon is 100% by mass, 0.5 to 30% by mass is preferable, and 2 to 30% by mass is more preferable.

The positive electrode and negative electrode are formed by, for example, (1) a method obtained by adding polytetrafluoroethylene to a mixture of activated carbon and acetylene black and then press-molding. (2) activated carbon and pitch, tar, phenol resin, etc. A method of mixing and molding the binder material and then heat-treating it under an inert atmosphere to obtain a sintered body, and (3) a method of sintering only activated carbon and the binder material or activated carbon to form an electrode are preferred. When using activated carbon fiber cloth obtained by activating carbon fiber cloth, it may be used as an electrode as it is without using a binder substance.

In the electric double layer capacitor, the polarizable electrode is prevented from contacting or short-circuiting by a method in which the separator is sandwiched between the polarizable electrodes or a method in which the polarizable electrodes are opposed to each other by using a holding means. Is preferred. As the separator, it is preferable to use a porous thin film that does not cause a chemical reaction with molten salt or the like in the operating temperature range. As the material of the separator, paper, polypropylene, polyethylene, glass fiber, and the like are suitable.
Examples of the shape of the electric double layer capacitor include a coin type, a wound type, a square type, and an aluminum laminate type, and any shape may be used.

Electrochemical devices such as lithium secondary batteries, electrolytic capacitors, and electric double layer capacitors using the electrolyte material according to the present invention include portable information terminals, portable electronic devices, small household electric power storage devices, motorcycles, electric vehicles, It can be suitably used for various applications such as a hybrid electric vehicle.

The electrolyte material of the present invention has the above-described configuration, improves ionic conductivity, is excellent in low-temperature characteristics, and is stable over time, and thus is suitable as an electrolyte material that constitutes an ion conductor. In addition, since it is not corrosive to electrodes, etc., it is suppressed from decomposition of the electrolyte salt even at a high potential, and is electrochemically stable. Therefore, primary batteries, lithium (ion) secondary batteries and fuels In addition to batteries having charging and discharging mechanisms such as batteries, the present invention can be suitably applied to electrochemical devices such as electrolytic capacitors, electric double layer capacitors, solar cells and electrochromic display elements.

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples. Unless otherwise specified, “part” means “part by weight” and “%” means “mass%”.

Example 1
An ion conductive material obtained by mixing 1% by mass of ion-exchanged water with ethylmethylimidazolium dicyanoamide (hereinafter referred to as EMImDCA) was obtained. As a result of measuring the ion conductivity of these ion conductive materials according to the following measuring method, 2.6 × 10 ⁻² S / cm (25 ° C.), 1.3 × 10 ⁻² S / cm (0 ° C.), 5 0.5 × 10 ⁻³ S / cm (−20 ° C.) and 2.7 × 10 ⁻⁶ S / cm (−55 ° C.). The results are shown in Table 1.

(Ion conductivity measurement method)
The ionic conductivity was measured by a complex impedance method using an SUS electrode and an impedance analyzer SI1260 (trade name; manufactured by Solartron) in an atmosphere of 25 ° C., 0 ° C., −20 ° C. and −55 ° C.

Examples 2-19 and Comparative Examples 1-5
Ionic conductivity was measured in the same manner as in Example 1 except that the types and amounts of ionic liquid and solvent as shown in Table 1 were used. These results are shown in Table 1.

Table 1 will be described below.
EMImDCA: Ethylmethylimidazolium dicyanoamide EMPyDCA: Ethylmethylpyrrolidinium dicyanoamide EMImTCM: Ethylmethylimidazolium tricyanomethide MeMeImDCA: Methylmethylimidazolium dicyanoamide TEMADCA: Triethylmethylammonium dicyanoamide TMImDCA: Trimethylimidazolium dicyanoamide GBL γ-butyrolactone EG: ethylene glycol

Example 20
Ethylmethylimidazolium tricyanomethide (EMImTCM) was diluted to 2% by mass with a mobile phase, and LC (liquid chromatography) analysis was performed to determine the peak reduction rate after the heat resistance test. The results are shown in Table 2. The heat resistance test and LC analysis were performed under the following test conditions, and the peak reduction rate was determined as described above.

(Heat resistance test)
The sample was hold | maintained at 150 degreeC for 50 hours using dryer DNF-400 (brand name; Yamato Scientific company make).
(LC analysis)
Measuring instrument: manufactured by Tosoh Corporation Detector: UV-8020 (ultraviolet absorption 254 nm)
Mobile phase: 10% aqueous methanol flow rate: 1.0 ml

Example 21
LC (liquid chromatography) analysis was carried out in the same manner as in Example 20 except that ethylmethylimidazolium dicyanoamide (EMImDCA) was used, and the peak reduction rate after the heat resistance test was determined. The results are shown in Table 2.

It is a cross-sectional schematic diagram which shows one form of a lithium secondary battery. (A) is a perspective view which shows one form of an electrolytic capacitor, (b) is a cross-sectional schematic diagram which shows one form of an aluminum electrolytic capacitor. It is the cross-sectional schematic diagram which shows one form of an electrical double layer capacitor, and the enlarged schematic diagram of the electrode surface.

Claims (6)

An electrolyte material containing an ionic compound,
The electrolytic solution material has the following general formula (1);

(Wherein X represents at least one element selected from B, C, N, O, Al, Si, P, S, As and Se. M ¹ and M ² are the same or different, An organic linking group, Q represents an organic group, a is an integer of 1 or more, and b, c, d, and e are integers of 0 or more. The electrolyte material is characterized by comprising 1 to 99% by mass of a solvent in 100% by mass of the electrolyte material. The anion having the cyano group is represented by the following general formula (2);

(Wherein X represents at least one element selected from B, C, N, O, Al, Si, P, S, As and Se. M ¹ and M ² are the same or different, Represents an organic linking group, Q represents an organic group, a is an integer of 1 or more, and b, c, and d are integers of 0 or more). The electrolyte material according to claim 1. 3. The electrolyte material according to claim 1, wherein the electrolyte material has a peak reduction rate of 50% or less after being heated at 150 ° C. for 50 hours. The electrolyte solution material according to claim 1, wherein X in the general formula (1) is a carbon element (C). The electrolytic solution material according to any one of claims 1 to 4, wherein the electrolytic solution material essentially comprises a nitrogen heterocyclic cation having a conjugated double bond. A lithium secondary battery, an electrolytic capacitor, or an electric double layer capacitor comprising the electrolytic solution material according to claim 1.

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