JP6061066B2 - Electrochemical capacitor - Google Patents

Description

  The present invention relates to an electrochemical capacitor, a nonaqueous electrolyte used therefor, and a method for producing the same. The present invention has a high energy density, a low internal resistance, a high withstand voltage, a rapid charge / discharge with a large current, and a stable high output in a wide temperature environment from a high temperature to a low temperature. The present invention relates to an electrochemical capacitor to be obtained, a nonaqueous electrolyte used therefor, and a method for producing the same.

Secondary batteries and electrochemical capacitors are actively developed as main power sources and auxiliary power sources for electric vehicles (EV) and hybrid vehicles (HEV), or as power storage devices for renewable energy such as solar power generation and wind power generation. It is advanced to.
Known electrochemical capacitors include electric double layer capacitors and hybrid capacitors.
An electric double layer capacitor (sometimes called a symmetric capacitor) uses a material having a large specific surface area such as activated carbon for both positive and negative electrode layers. An electric double layer is formed at the interface between the electrode layer and the electrolytic solution, and electricity is stored by a non-Faraday reaction without redox. An electric double layer capacitor generally has a higher output density and excellent rapid charge / discharge characteristics than a secondary battery.
The electrostatic energy J of the capacitor is defined by the formula: J = (1/2) × CV ² . C is a capacitance and V is a withstand voltage. The withstand voltage of the electric double layer capacitor is as low as about 2.7 to 3.3V. Therefore, the electrostatic energy of the electric double layer capacitor is 1/10 or less of the secondary battery.

  A hybrid capacitor (sometimes referred to as an asymmetric capacitor) has a positive electrode layer and a negative electrode layer made of different materials facing each other in an electrolyte containing lithium ions via a separator. With this configuration, the positive electrode layer can store electricity by a non-Faraday reaction that does not involve redox, and the negative electrode layer can store electricity by a Faraday reaction that involves oxidation and reduction, thereby generating a large capacitance C. For this reason, it is expected that the hybrid capacitor will obtain a larger energy density than the electric double layer capacitor.

  However, since electrochemical capacitors have been used as electrolytes from the viewpoint of ionic conductivity, various safety measures are necessary because there is a risk of equipment damage due to liquid leakage. It is a barrier for capacitor development.

On the other hand, Patent Document 1 proposes a solid electrolyte such as an organic polymer material. This uses a solid electrolyte instead of a liquid as the electrolyte, so there are no problems such as liquid leakage and is advantageous in terms of safety, but there is a problem that the ionic conductivity is low, and since a separator is used, the capacitance is There was also a problem of becoming smaller.
Patent Document 2 proposes a capacitor having a structure in which a gap is formed by removing a salt of the ion exchange resin using an ion exchange resin, and the gap is filled with an electrolytic solution. However, an extra step is required to produce the gap, making it difficult to manufacture, and know-how is also required to inject the electrolyte into the gap, and it cannot be easily produced.

JP 2000-150308 A JP 2006-73980 A

  In view of the circumstances as described above, an object of the present invention is to provide an electrochemical capacitor having basic performance as a capacitor, high capacity without using a separator, excellent charge / discharge characteristics, and excellent safety and reliability. That is. Moreover, since a separator is not used, it can be manufactured at low cost.

  As a result of intensive studies to solve the above problems, the present inventors have appropriately selected a specific polyether copolymer and electrolyte salt solution as an electrolyte between the negative electrode and the positive electrode, and sandwiched between the two electrodes. Thus, the inventors have found that an electrochemical capacitor having basic performance as a capacitor, high capacity, excellent charge / discharge characteristics, and excellent safety and reliability can be obtained, and the present invention has been completed.

Item 1
At least a negative electrode,
Formula (1):
[Wherein, R represents an alkyl group having 1 to 12 carbon atoms, or —CH ₂ O (CR ¹ R ² R ³ ). R ¹ , R ² and R ³ are hydrogen atoms or —CH ₂ O (CH ₂ CH ₂ O) _n R ⁴ , and n and R ⁴ may be different among R ¹ , R ² and R ^3. . R ⁴ is an alkyl group having 1 to 12 carbon atoms or an aryl group which may have a substituent, and n is an integer of 0 to 12. And 0 to 90 mol% of repeating units derived from the monomer represented by formula (2):
99 to 10 mol% of repeating units derived from the monomer represented by formula (3)
[Wherein, R ⁵ is a group having an ethylenically unsaturated group. Comprising a polyether copolymer or a cross-linked product thereof and an electrolyte salt compound, and a positive electrode, comprising a repeating unit derived from a monomer represented by the formula: It is an electrochemical capacitor characterized by not using.
Item 2
Item 2. The electrochemical capacitor according to Item 1, wherein the electrolyte composition contains an aprotic organic solvent or a room temperature molten salt.
Item 3
Item 3. The electrochemical capacitor according to Item 1 or 2, wherein the negative electrode has a mixture of a negative electrode active material, a conductive additive, and a binder, and the negative electrode active material is graphite or activated carbon.
Item 4
Item 4. The electrochemical capacitor according to Item 3, wherein the negative electrode is doped with lithium.
Item 5
Item 5. The electrochemical capacitor according to any one of Items 1 to 4, wherein the positive electrode has a mixture of a positive electrode active material, a conductive additive, and a binder, and the positive electrode active material is activated carbon.

  According to the present invention, the basic composition as a capacitor is provided by sandwiching an electrolyte composition containing a specific polyether copolymer and an electrolyte salt compound between a negative electrode and a positive electrode without using a separator. It is possible to obtain an electrochemical capacitor that has excellent capacitance and charge / discharge characteristics, and is excellent in safety and reliability.

  Hereinafter, the configuration of the present invention will be described in detail.

The compound of the formula (1) can be easily synthesized by obtaining it from a commercial product or by a general ether synthesis method from epihalohydrin and alcohol. Examples of commercially available compounds include propylene oxide, butylene oxide, methyl glycidyl ether, ethyl glycidyl ether, butyl glycidyl ether, t-butyl glycidyl ether, benzyl glycidyl ether, 1,2-epoxydodecane, 1,2 -Epoxy octane, 1,2-epoxyheptane, 2-ethylhexyl glycidyl ether, 1,2-epoxydecane, 1,2-epoxyhexane, glycidyl phenyl ether, 1,2-epoxypentane, glycidyl isopropyl ether, etc. can be used. . Among these commercially available products, propylene oxide, butylene oxide, methyl glycidyl ether, ethyl glycidyl ether, butyl glycidyl ether, and glycidyl isopropyl ether are preferable, and propylene oxide, butylene oxide, methyl glycidyl ether, and ethyl glycidyl ether are particularly preferable.
In the monomer represented by the formula (1) obtained by synthesis, R is preferably —CH ₂ O (CR ¹ R ² R ³ ), and at least one of R ¹ , R ² , and R ³ is —CH ₂ O. it is preferably _{(CH 2 CH 2 O) n} R 4. R ⁴ is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably 1 to 4 carbon atoms. n is preferably from 2 to 6, and more preferably from 2 to 4.

  The compound of the formula (2) is a basic chemical product, and a commercially available product can be easily obtained.

In the compound of formula (3), R ⁵ is a substituent containing an ethylenically unsaturated group. Examples of the monomer component containing an ethylenically unsaturated group include allyl glycidyl ether, 4-vinylcyclohexyl glycidyl ether, α-terpinyl glycidyl ether, cyclohexenyl methyl glycidyl ether, p-vinylbenzyl glycidyl ether, allyl phenyl glycidyl ether, vinyl Glycidyl ether, 3,4-epoxy-1-butene, 3,4-epoxy-1-pentene, 4,5-epoxy-2-pentene, 1,2-epoxy-5,9-cyclododecandiene, 3,4 -Epoxy-1-vinylcyclohexene, 1,2-epoxy-5-cyclooctene, glycidyl acrylate, glycidyl methacrylate, glycidyl sorbate, glycidyl cinnamate, glycidyl crotonic acid, glycidyl-4-hexenoate Preferred are allyl glycidyl ether, glycidyl acrylate, and glycidyl methacrylate.

The copolymer of the present invention comprises (A): a repeating unit derived from the monomer of formula (1)
[Wherein, R represents an alkyl group having 1 to 12 carbon atoms, or —CH ₂ O (CR ¹ R ² R ³ ). R ¹ , R ² and R ³ are hydrogen atoms or —CH ₂ O (CH ₂ CH ₂ O) _n R ⁴ , and n and R ⁴ may be different among R ¹ , R ² and R ^3. . R ⁴ is an alkyl group having 1 to 12 carbon atoms, and n is an integer of 0 to 12. And (B): a repeating unit derived from the monomer of formula (2), and
And if necessary
[Wherein, R ⁵ is a group having an ethylenically unsaturated group. ]
Consists of

  Here, the repeating units (A) and (C) may each be derived from two or more different monomers.

The polyether copolymer of the present invention can be synthesized as follows. As a ring-opening polymerization catalyst, a catalyst system mainly composed of organic aluminum, a catalyst system mainly composed of organic zinc, a coordination anion initiator such as an organic tin-phosphate ester condensate catalyst system, or potassium containing K ⁺ as a counter ion By using an anionic initiator such as alkoxide, diphenylmethyl potassium, potassium hydroxide, and the like, each of the monomers is reacted in the presence or absence of a solvent at a reaction temperature of 10 to 120 ° C. with stirring to obtain a polyether copolymer. can get. From the viewpoint of the degree of polymerization or the properties of the resulting copolymer, a coordination anion initiator is preferred, and an organotin-phosphate ester condensate catalyst system is particularly preferred because of ease of handling.

  In the polyether copolymer of the present invention, the molar ratio of the repeating unit (A), the repeating unit (B) and the repeating unit (C) is (A) 0 to 90 mol%, (B) 99 to 10 mol%. And (C) 0-15 mol% is preferred, more preferably (A) 0-70 mol%, (B) 98-30 mol%, and (C) 0-13 mol%, more preferably (A). 0 to 50 mol%, (B) 98 to 50 mol%, and (C) 0 to 11 mol%. If the repeating unit (B) exceeds 99 mol%, the glass transition temperature rises and the oxyethylene chain crystallizes, resulting in a marked deterioration of the ionic conductivity of the electrolyte. In general, it is known that ion conductivity is improved by reducing the crystallinity of polyethylene oxide, but the polyether copolymer of the present invention is remarkably superior in this respect.

  The molecular weight of the polyether copolymer of the present invention is preferably 10,000 to 2,500,000, more preferably 50,000 to 2,000,000, in order to obtain good processability, mechanical strength and flexibility. Those within the range of 100,000 to 1.8 million are suitable.

  The polyether copolymer before cross-linking of the present invention may be any copolymer type such as a block copolymer or a random copolymer. Random copolymers are preferred because they have a greater effect of reducing the crystallinity of polyethylene oxide.

The electrolyte composition of the present invention contains an electrolyte salt compound in the polyether copolymer or a cross-linked product thereof. The electrolyte composition containing the electrolyte salt compound in the cross-linked product may be impregnated with the electrolyte salt compound in the cross-linked product of the above-mentioned polyether copolymer, and when the polyether copolymer is cross-linked, It may be obtained by crosslinking a polymer and an electrolyte salt compound.
The electrolyte composition of the present invention may be in the form of a polymer electrolyte gel obtained by further coexisting an aprotic organic solvent with respect to the polyether copolymer and the electrolyte salt compound, and is more preferable. In order to strengthen the gel, the gel may be crosslinked by applying heat in the presence or absence of a thermal polymerization initiator or a photoinitiator, or by irradiating an active energy ray such as ultraviolet rays. It is preferable to crosslink from the point that a special separator is not required and the gel also serves as a separator.

Examples of the thermal polymerization initiator that can be used in the present invention include radical initiators selected from organic peroxides, azo compounds, and the like.
Examples of organic peroxides include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxyesters, and the like that are usually used for crosslinking. Bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di ( t-Butylperoxy) hexane, benzoyl peroxide, t-butylperoxy-2-ethylhexanoate and the like.

As the azo compound system, those commonly used for crosslinking such as an azonitrile compound, an azoamide compound, an azoamidine compound, etc. are used. 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methyl) Butyronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2-azobis (2-methyl-N-phenylpropionamidine) dihydrochloride, 2,2 ′ -Azobis [2- (2-imidazolin-2-yl) propane], 2,2'-azobis [2-methyl-N- (2-hydroxyethyl) propionamide], 2,2'-azobis (2-methyl) Propane), 2,2′-azobis [2- (hydroxymethyl) propionitrile] and the like.
Preferably, an organic peroxide-based initiator is used, and two or more kinds of these compounds can be used in combination.

  As the active energy ray used for crosslinking by light, ultraviolet rays, visible rays, electron beams and the like can be used. In particular, ultraviolet rays are preferable because of the price of the apparatus and ease of control.

  Examples of the photoreaction initiator that can be used in the present invention include alkylphenone series, benzophenone series, acylphosphine oxide series, titanocenes, triazines, bisimidazoles, and oxime esters. Preferably, an alkylphenone-based, benzophenone-based, or acylphosphine oxide-based photoinitiator is used. Two or more kinds of the aforementioned compounds can be used in combination as a photoreaction initiator.

  Specific examples of the alkylphenone photoinitiator include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl. -Propan-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1- [4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl] -2-methyl-propan-1-one and the like. 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxycyclohexyl-phenyl-ketone and 2-hydroxy-2-methyl-1-phenyl-propan-1-one are preferred.

  Specific examples of the benzophenone photoinitiator include benzophenone, 2-chlorobenzophenone, 4,4′-bis (diethylamino) benzophenone, 4,4′-bis (dimethylamino) benzophenone, methyl-2-benzoylbenzoate, and the like. Can be mentioned. Benzophenone, 4,4′-bis (diethylamino) benzophenone, and 4,4′-bis (dimethylamino) benzophenone are preferred.

  Specific examples of the acylphosphine oxide photoreaction polymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and the like. It is done. Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide is preferred.

The amount of the thermal polymerization initiator used for the crosslinking reaction is preferably in the range of 0.01 to 10 parts by weight, more preferably 0.1 to 4.0 parts by weight with respect to 100 parts by weight of the polyether copolymer. .
The amount of the photoinitiator used for the crosslinking reaction is preferably in the range of 0.01 to 6.0 parts by weight, more preferably 0.1 to 4.0 parts by weight with respect to 100 parts by weight of the polyether copolymer. It is.

In the present invention, a crosslinking aid may be used in combination with a photoreaction initiator. Crosslinking aid is usually polyfunctional compound - a _{(e.g., CH 2 = CH-, CH 2} = CH-CH 2, CF 2 = CF- at least two containing compound). Specific examples of the crosslinking aid include triallyl cyanurate, triallyl isocyanurate, triacryl formal, triallyl trimellitate, N, N′-m-phenylene bismaleimide, dipropargyl terephthalate, diallyl phthalate, tetraallyl terephthalate Amides, triallyl phosphate, hexafluorotriallyl isocyanurate, N-methyltetrafluorodiallyl isocyanurate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate and the like.

In the case of using a heat, the crosslinking reaction can be carried out by heating at a temperature setting from room temperature to about 200 ° C. for about 10 minutes to 24 hours. In the case of using ultraviolet rays, a xenon lamp, a mercury lamp, a high-pressure mercury lamp, and a metal halide lamp can be used, for example, by irradiating the electrolyte with a wavelength of 365 nm and a light amount of 1 to 50 mW / cm ² for 0.1 to 30 minutes. Can do.

  The electrolyte salt compound that can be used in the present invention is preferably compatible with a mixture comprising a polyether copolymer or a crosslinked product of the copolymer and an aprotic organic solvent. Here, “compatible” means a state in which the electrolyte salt compound does not precipitate due to crystallization or the like.

In the present invention, the following electrolyte salt compounds are preferably used. That is, a cation selected from metal cation, ammonium ion, amidinium ion, and guanidinium ion, chloride ion, bromide ion, iodide ion, perchlorate ion, thiocyanate ion, tetrafluoroboric acid Ion, nitrate ion, AsF ₆ ⁻ , PF ₆ ⁻ , stearyl sulfonate ion, octyl sulfonate ion, dodecylbenzene sulfonate ion, naphthalene sulfonate ion, dodecyl naphthalene sulfonate ion, 7,7,8,8-tetracyano- p-quinodimethane ion, X ₁ SO ₃ ⁻ , [(X ₁ SO ₂ ) (X ₂ SO ₂ ) N] ⁻ , [(X ₁ SO ₂ ) (X ₂ SO ₂ ) (X ₃ SO ₂ ) C ] ^-, and _{[(X 1 SO 2) (} X 2 SO 2) YC] - composed of a selected anionic from compound And the like. _{However, X 1, X 2, X} 3, and Y is an electron withdrawing group. Preferably, X ₁ , X ₂ and X ₃ are each independently a C 1-6 perfluoroalkyl group or a C 6-18 perfluoroaryl group, Y is a nitro group, a nitroso group, A carbonyl group, a carboxyl group or a cyano group; X ₁ , X ₂ and X ₃ may be the same or different.

As the metal cation, a cation of a transition metal can be used. Preferably, a metal cation selected from Mn, Fe, Co, Ni, Cu, Zn, and Ag metal is used. In addition, preferable results can be obtained by using a metal cation selected from Li, Na, K, Rb, Cs, Mg, Ca, and Ba metals. Two or more of the aforementioned compounds can be used in combination as the electrolyte salt compound.
In particular, as an electrolyte salt compound in a lithium ion capacitor, a Li salt compound is preferably used.

As the Li salt compound, a Li salt compound having a wide potential window, which is generally used for lithium ion capacitors, is used. For example, LiBF ₄ , LiPF ₆ , LiClO ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN [CF ₃ SC (C ₂ F ₅ SO ₂ ) ₃ ] ₂ etc. are mentioned, but it is not limited to these. These may be used alone or in combination of two or more.

  Moreover, a normal temperature molten salt can be used as the electrolyte salt compound. When a room temperature molten salt is used as an electrolyte, from the physical property inherent to the salt being a liquid at room temperature, the addition of this alone as a solvent similar to the case where an aprotic organic solvent is further added. The effect can be exhibited together.

  The room temperature molten salt refers to a salt that is at least partially in a liquid state at room temperature, and the room temperature refers to a temperature range in which the power supply is assumed to normally operate. The temperature range in which the power supply is assumed to normally operate has an upper limit of about 120 ° C. and in some cases about 60 ° C., and a lower limit of about −40 ° C. and in some cases about −20 ° C.

  The room temperature molten salt is also called an ionic liquid, and pyridine, aliphatic amine and alicyclic amine quaternary ammonium organic cations are known. Examples of the quaternary ammonium organic cation include imidazolium ions such as dialkylimidazolium and trialkylimidazolium, tetraalkylammonium ions, alkylpyridinium ions, pyrazolium ions, pyrrolidinium ions, and piperidinium ions. In particular, an imidazolium cation is preferable.

  Examples of the imidazolium cation include dialkyl imidazolium ions and trialkyl imidazolium ions. Examples of the dialkylimidazolium ion include 1,3-dimethylimidazolium ion, 1-ethyl-3-methylimidazolium ion, 1-methyl-3-ethylimidazolium ion, 1-methyl-3-butylimidazolium ion, 1 -Butyl-3-methylimidazolium ion and the like. Examples of the trialkylimidazolium ion include 1,2,3-trimethylimidazolium ion, 1,2-dimethyl-3-ethylimidazolium ion, 1,2- Examples thereof include, but are not limited to, dimethyl-3-propylimidazolium ion and 1-butyl-2,3-dimethylimidazolium ion.

  Examples of the tetraalkylammonium ion include, but are not limited to, trimethylethylammonium ion, dimethyldiethylammonium ion, trimethylpropylammonium ion, trimethylhexylammonium ion, and tetrapentylammonium ion.

  Alkylpyridinium ions include N-methylpyridinium ion, N-ethylpyridinium ion, N-propylpyridinium ion, N-butylpyridinium ion, 1-ethyl-2methylpyridinium ion, 1-butyl-4-methylpyridinium ion 1-butyl-2,4 dimethylpyridinium ion and the like, but are not limited thereto.

  In addition, the normal temperature molten salt which has these cations may be used independently, or may mix and use 2 or more types.

As anions, halide ions such as chloride ions, bromide ions and iodide ions, perchlorate ions, thiocyanate ions, tetrafluoroborate ions, nitrate ions, inorganic acid ions such as AsF ₆ ⁻ and PF ₆ ⁻ Organic acid ions such as stearyl sulfonate ion, octyl sulfonate ion, dodecylbenzene sulfonate ion, naphthalene sulfonate ion, dodecyl naphthalene sulfonate ion, 7,7,8,8-tetracyano-p-quinodimethane ion, etc. Is exemplified.

  In the present invention, the content of the electrolyte salt compound is preferably 0.1 to 3.0 mol / L, and particularly preferably 1.0 to 2.0 mol / L. When the content of the electrolyte salt compound is less than 0.1 mol / L, the resistance of the electrolyte is large, and the large current / low temperature discharge characteristics are deteriorated. When it exceeds 3.0 mol / L, the solubility is poor and crystals are precipitated. Or

  In the present invention, the amount of the electrolyte salt compound used for the polyether copolymer is preferably 1 to 120 parts by weight, more preferably 3 to 90 parts by weight with respect to 10 parts by weight of the polyether copolymer. Is good.

  In the present invention, an aprotic organic solvent or an ionic liquid (hereinafter referred to as “aprotic organic solvent or the like”) can be added. The electrolyte composition of the present invention is easily gelled by combining with an aprotic organic solvent or the like. Here, the gel refers to a non-fluid soft body swollen by a solvent.

  As the aprotic organic solvent, aprotic nitriles, ethers and esters are preferable. Specifically, acetonitrile, propylene carbonate, γ-butyrolactone, butylene carbonate, vinyl carbonate, ethylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl monoglyme, methyl diglyme, methyl triglyme, methyl tetraglyme, ethyl Monoglyme, ethyldiglyme, ethyltriglyme, ethylmethylmonoglyme, butyldiglyme, 3-methyl-2-oxazolidone, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4,4-methyl-1,3 -Dioxolane, methyl formate, methyl acetate, methyl propionate, etc., among which propylene carbonate, γ-butyrolactone, butylene carbonate, vinyl carbonate Bonate, ethylene carbonate, methyl triglyme, methyl tetraglyme, ethyl triglyme, and ethyl methyl monoglyme are preferred. A mixture of two or more of these may be used.

There is no particular limitation on the method of mixing the electrolyte salt compound and the necessary aprotic organic solvent into the polyether copolymer, but the polyether copolymer is added to the solution containing the electrolyte salt compound and the necessary aprotic organic solvent. A method of soaking for a long time, a method of mechanically mixing an electrolyte salt compound and a necessary aprotic organic solvent into a polyether copolymer, a polyether copolymer and an electrolyte salt compound as an aprotic organic solvent There is a method of dissolving and mixing, or a method of once dissolving the polyether copolymer in another solvent and then mixing an aprotic organic solvent. Other polar solvents such as tetrahydrofuran, acetone, acetonitrile, dimethylformamide, dimethyl sulfoxide, dioxane, methyl ethyl ketone, methyl isobutyl ketone, etc. used alone or in combination are used as other solvents in the case of producing using other solvents. It is done. The other solvent can be removed before, during or after crosslinking when the polyether copolymer is crosslinked.
In order to maintain the non-flowing state of the electrolyte composition as a gel that does not require a separator in accordance with the spirit of the present invention, the viscosity of the electrolyte composition may be 8 Pa · S or more in the battery use environment.

(Method for manufacturing electrode)
The electrode for an electrochemical capacitor of the present invention comprises a current collector serving as an electrode substrate, a positive electrode or negative electrode active material, a conductive agent that exchanges good ions with the electrolyte layer, and a positive electrode or negative electrode active material serving as an electrode substrate. It is preferable to have a binder for fixing to the electric body, and it can be obtained by forming an electrode composition for an electrochemical capacitor comprising this active material, a conductive additive, and a binder on a current collector to be an electrode substrate.
Specifically, a method of laminating an electrode composition for an electrochemical capacitor formed into a sheet shape on a current collector (kneading sheet forming method); an electrode composition for an electrochemical capacitor in a paste shape on a current collector Examples include a method of applying and drying (wet molding method); a method of preparing composite particles of an electrode composition for an electrochemical capacitor, and sheet molding and roll pressing on a current collector (dry molding method). Among these, a wet molding method and a dry molding method are preferable, and a wet molding method is more preferable.

(Current collector)
As a material of the current collector used for the electrode for an electrochemical capacitor of the present invention, for example, metal, carbon, conductive polymer, etc. can be used, and metal is preferably used. As the current collector metal, aluminum, platinum, nickel, tantalum, titanium, stainless steel, copper, other alloys and the like are usually used. As the current collector used for the electrode for the lithium ion capacitor, it is preferable to use copper, aluminum, or an aluminum alloy from the viewpoint of conductivity and voltage resistance.

  Examples of the shape of the current collector used for the electrode for an electrochemical capacitor of the present invention include current collectors such as metal foil and metal edge foil; current collectors having through-holes such as expanded metal, punching metal, and mesh. A collector having a through-hole is preferable in that it can reduce the diffusion resistance of electrolyte ions and improve the output density of the electrochemical capacitor, and expanded metal and punching metal are particularly preferable in that it has excellent electrode strength. preferable.

  10-80 area% is preferable, as for the ratio of the hole of the electrical power collector which has the hole penetrated suitably used for the electrode for electrochemical capacitors of this invention, More preferably, it is 20-60 area%, More preferably, it is 30-50 area %. When the ratio of the penetrating holes is within this range, the diffusion resistance of the electrolytic solution is reduced, and the internal resistance of the lithium ion capacitor is reduced.

  The thickness of the current collector used for the electrochemical capacitor electrode of the present invention is preferably 5 to 100 μm, more preferably 10 to 70 μm, and particularly preferably 20 to 50 μm.

(Active material)
Specifically, as the electrode active material used for the positive electrode of the electrode for an electrochemical capacitor of the present invention, specifically, an allotrope of carbon is usually used, and electrode active materials used in electric double layer capacitors can be widely used. Specific examples of the allotrope of carbon include activated carbon, polyacene (PAS), carbon whisker, and graphite, and these powders or fibers can be used. Among these, activated carbon is preferable. Specific examples of the activated carbon include activated carbon made from phenol resin, rayon, acrylonitrile resin, pitch, coconut shell, and the like. When carbon allotropes are used in combination, two or more types of carbon allotropes having different average particle diameters or particle size distributions may be used in combination. Moreover, as an electrode active material used for the positive electrode, in addition to the above materials, a polyacene-based skeleton structure which is a heat-treated product of an aromatic condensation polymer and has an atomic ratio of hydrogen atom / carbon atom of 0.50 to 0.05 A polyacene-based organic semiconductor (PAS) having the following can also be suitably used.

  The electrode active material used for the negative electrode of the electrode for an electrochemical capacitor of the present invention may be any material that can reversibly carry cations. Specifically, electrode active materials used in the negative electrode of lithium ion secondary batteries can be widely used. Of these, crystalline carbon materials such as graphite and non-graphitizable carbon, carbon materials such as hard carbon and coke, and polyacene-based materials (PAS) described as the electrode active material of the positive electrode are preferable. These carbon materials and PAS are obtained by carbonizing a phenol resin or the like, activated as necessary, and then pulverized.

  The shape of the electrode active material used in the electrode composition for an electrochemical capacitor is preferably a granulated particle. When the shape of the particles is spherical, a higher density electrode can be formed during electrode molding.

  The volume average particle diameter of the electrode active material used for the electrode composition for an electrochemical capacitor is usually 0.1 to 100 μm, preferably 0.5 to 50 μm, more preferably 1 to 20 μm for both the positive electrode and the negative electrode. These electrode active materials can be used alone or in combination of two or more.

(Conductive aid)
The conductive assistant used in the electrode composition for an electrochemical capacitor of the present invention is an allotrope of particulate carbon having conductivity and no pores capable of forming an electric double layer, specifically, Examples thereof include conductive materials such as conductive carbon black such as graphite, furnace black, acetylene black, and ketjen black (registered trademark of Akzo Nobel Chemicals Bethloten Fennaut Shap). Among these, acetylene black and furnace black are preferable.

  The volume average particle diameter of the conductive additive used in the electrode composition for an electrochemical capacitor of the present invention is preferably smaller than the volume average particle diameter of the electrode active material, and the range is usually 0.001 to 10 μm, preferably 0. 0.005 to 5 μm, more preferably 0.01 to 1 μm. When the volume average particle diameter of the conductive additive is within this range, high conductivity can be obtained with a smaller amount of use. These conductive assistants can be used alone or in combination of two or more. The amount of the conductive assistant is usually preferably 0.1 to 50 parts by weight, more preferably 0.5 to 15 parts by weight, and still more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. . When the amount of the conductive additive is within this range, the capacity of the electrochemical capacitor using the obtained electrochemical capacitor electrode can be increased and the internal resistance can be decreased.

(binder)
For example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorine-based rubber, or styrene butadiene rubber (SBR) can be used as the binder used for the electrochemical capacitor electrode of the present invention. It is not limited.

Moreover, Formula (1):
[Wherein, R represents an alkyl group having 1 to 12 carbon atoms, or —CH ₂ O (CR ¹ R ² R ³ ). R ¹ , R ² and R ³ are hydrogen atoms or —CH ₂ O (CH ₂ CH ₂ O) _n R ⁴ , and n and R ⁴ may be different among R ¹ , R ² and R ^3. . R ⁴ is an alkyl group having 1 to 12 carbon atoms or an aryl group which may have a substituent, and n is an integer of 0 to 12. And 0 to 90 mol% of repeating units derived from the monomer represented by formula (2):
99 to 10 mol% of repeating units derived from the monomer represented by formula (3)
[Wherein R ⁵ is a group having an ethylenically unsaturated group. By using a polyether copolymer obtained by polymerizing a monomer represented by 0 to 15 mol% of a repeating unit derived from the monomer represented by formula (1) or a crosslinked product thereof as a binder, It can be moved.

  The glass transition temperature (Tg) of the binder used in the electrode composition for an electrochemical capacitor of the present invention is preferably 50 ° C. or lower, more preferably −40 to 0 ° C. When the glass transition temperature (Tg) of the binder is within this range, it is excellent in binding property with a small amount of use, strong in electrode strength, rich in flexibility, and easily increases the electrode density by a pressing process at the time of electrode formation. Can do.

  The number average particle size of the binder in the electrode composition for an electrochemical capacitor of the present invention is not particularly limited, but is usually 0.0001 to 100 μm, preferably 0.001 to 10 μm, more preferably 0.01 to The number average particle diameter is 1 μm. When the number average particle diameter of the binder is within this range, an excellent binding force can be imparted to the polarizable electrode even when used in a small amount. Here, the number average particle diameter is a number average particle diameter calculated as an arithmetic average value obtained by measuring the diameter of 100 binder particles randomly selected in a transmission electron micrograph. The shape of the particles can be either spherical or irregular. These binders can be used alone or in combination of two or more. The amount of the binder is usually 0.1 to 50 parts by weight, preferably 0.5 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When the amount of the binder is within this range, sufficient adhesion between the obtained electrode composition layer and the current collector can be ensured, the capacity of the electrochemical capacitor can be increased, and the internal resistance can be decreased.

In the present invention, for the production of the positive electrode and the negative electrode, the current collector sheet was coated with a slurry prepared by adding the positive electrode / negative electrode active material, the conductive auxiliary agent, and the binder to a solvent. After drying, pressure bonding is performed at a pressure of 0 to 5 ton / cm ² , particularly 0 to ² ton / cm ² , 200 ° C. or higher, preferably 250 to 500 ° C., more preferably 250 to 450 ° C., for 0.5 to 20 hours. In particular, it is preferable to use one fired for 1 to 10 hours.

  In the electrochemical capacitor of the present invention, so-called doping may be performed in which lithium ions are occluded in the positive electrode and / or the negative electrode in advance. The means for doping the positive electrode and / or the negative electrode is not particularly limited. For example, it may be due to physical contact between a lithium ion supply source and a positive electrode or a negative electrode, or may be electrochemically doped.

  An electrode composition for an electrochemical capacitor is applied on the negative electrode or the positive electrode, and a transfer sheet-like film subjected to necessary crosslinking is transferred to form an electrolyte composition layer. Electrochemical capacitors can also be assembled by superimposing them.

  An electrochemical capacitor can also be assembled by impregnating or injecting a gelled material between a negative electrode and a positive electrode by incorporating an aprotic organic solvent having a high boiling point or a room temperature molten salt into the electrolyte composition. It is done.

As an example of the manufacturing method of the electrochemical capacitor of the present invention,
(A) Formula (1):
[Wherein, R represents an alkyl group having 1 to 12 carbon atoms, or —CH ₂ O (CR ¹ R ² R ³ ). R ¹ , R ² and R ³ are hydrogen atoms or —CH ₂ O (CH ₂ CH ₂ O) _n R ⁴ , and n and R ⁴ may be different among R ¹ , R ² and R ^3. . R ⁴ is an alkyl group having 1 to 12 carbon atoms or an aryl group which may have a substituent, and n is an integer of 0 to 12. And 0 to 90 mol% of repeating units derived from the monomer represented by formula (2):
99 to 10 mol% of repeating units derived from the monomer represented by formula (3)
[Wherein R ⁵ is a group having an ethylenically unsaturated group. A step of obtaining a polyether copolymer obtained by polymerizing a monomer represented by 0 to 15 mol% of a repeating unit derived from the monomer represented by
(B) injecting a composition containing the polyether copolymer, photoreaction initiator or thermal polymerization initiator, and electrolyte salt compound between the negative electrode material and the positive electrode material;
(C) crosslinking the injected composition;
The manufacturing method containing is illustrated.

In the polymerization step (A), the monomers represented by the above formula (1), formula (2) and formula (3) are polymerized to obtain a polyether copolymer. As a ring-opening polymerization catalyst, a catalyst system mainly composed of organic aluminum, a catalyst system mainly composed of organic zinc, a coordination anion initiator such as an organic tin-phosphate ester condensate catalyst system, or potassium containing K ⁺ as a counter ion By using an anionic initiator such as alkoxide, diphenylmethyl potassium, potassium hydroxide, and the like, each of the monomers is reacted in the presence or absence of a solvent at a reaction temperature of 10 to 120 ° C. with stirring to obtain a polyether copolymer. can get. From the viewpoint of the degree of polymerization or the properties of the resulting copolymer, a coordination anion initiator is preferred, and an organotin-phosphate ester condensate catalyst system is particularly preferred because of ease of handling.

In the coating step (B), a polyether copolymer, a photoreaction initiator, and an electrolyte salt compound are mixed to obtain an electrolyte composition, and the electrolyte composition is injected between the negative electrode material and the positive electrode material.
In the coating step (B), the electrolyte composition may be applied to one surface of either the negative electrode material or the positive electrode material, or the electrolyte composition may be applied to both surfaces of the negative electrode material or the positive electrode material. .

  In the crosslinking step (C), the injected electrolyte composition is crosslinked to form a crosslinked body layer of the electrolyte composition on the electrode material. Crosslinking can be performed by irradiating active energy rays in the presence or absence of an aprotic organic solvent. Specific examples of the active energy rays are electromagnetic waves such as ultraviolet rays, visible rays, infrared rays, X-rays, gamma rays and laser rays, and particle rays such as alpha rays, beta rays and electron rays.

  After forming a crosslinked body of the electrolyte composition by the crosslinking step (C), an electrochemical capacitor having a structure of negative electrode material / electrolyte composition / positive electrode material is obtained.

  In the present invention, an electrochemical capacitor may be produced by applying an electrolyte composition film to an electrode material. The electrolyte composition film can be produced by producing an electrolyte composition, applying the electrolyte composition to, for example, a release sheet, crosslinking on the release sheet, and peeling from the release sheet.

EXAMPLES Specific modes for carrying out the present invention will be described below with reference to examples. However, the present invention is not limited to the following examples without departing from the gist thereof.
In this example, the following experiment was conducted in order to compare the capacity and the retention rate of an electrochemical capacitor composed of a negative electrode material, a non-aqueous electrolyte, and a positive electrode material.

[Synthesis Example (Production of Polyether Copolymer Catalyst)]
In a three-necked flask equipped with a stirrer, thermometer and distillation apparatus, 10 g of tributyltin chloride and 35 g of tributyl phosphate are added and heated at 250 ° C. for 20 minutes with stirring under a nitrogen stream to distill off the distillate. As a product, a solid condensate was obtained. It used as a polymerization catalyst in the following polymerization examples.

The monomer equivalent composition of the polyether copolymer was determined by ¹ H NMR spectrum.
For measuring the molecular weight of the polyether copolymer, gel permeation chromatography (GPC) measurement was performed, and the weight average molecular weight was calculated in terms of standard polystyrene. GPC measurement was performed at 60 ° C. using RID-6A manufactured by Shimadzu Corporation, Showdex KD-807, KD-806, KD-806M and KD-803 columns manufactured by Showa Denko KK, and DMF as a solvent. .

[Polymerization Example 1]
The inside of a glass four-necked flask having an internal volume of 3 L was purged with nitrogen, and 1 g of the condensate shown in the synthesis example of the catalyst as a polymerization catalyst and a glycidyl ether compound (a) adjusted to a water content of 10 ppm or less:
158 g, allyl glycidyl ether 22 g, and n-hexane 1000 g as a solvent were charged, and 125 g of ethylene oxide was sequentially added while monitoring the polymerization rate of the compound (a) by gas chromatography. The polymerization temperature at this time was 20 ° C., and the reaction was carried out for 10 hours. The polymerization reaction was stopped by adding 1 mL of methanol. After taking out the polymer by decantation, it was dried at 40 ° C. under normal pressure for 24 hours and further under reduced pressure at 45 ° C. for 10 hours to obtain 280 g of polymer. Table 1 shows the weight average molecular weight and monomer conversion composition analysis results of the obtained polyether copolymer.

[Polymerization Example 2]
The same operation as in Polymerization Example 1 was performed except that 65 g of glycidyl ether compound (a), 30 g of allyl glycidyl ether, and 205 g of ethylene oxide were used for polymerization.

[Polymerization Example 3]
The same operation as in Polymerization Example 1 was carried out except that 171 g of glycidyl ether compound (a), 21 g of allyl glycidyl ether, 108 g of ethylene oxide, and 0.02 g of n-butanol were polymerized.

[Polymerization Example 4]
The same operation as in Polymerization Example 1 was performed except that 167 g of glycidyl ether compound (a) and 140 g of ethylene oxide were charged and polymerized.

[Polymerization Example 5]
The inside of a glass 4-necked flask having an internal volume of 3 L was purged with nitrogen, and 2 g of the condensate shown in the catalyst production example as a catalyst, 50 g of glycidyl methacrylate adjusted to a water content of 10 ppm or less, and 1000 g of n-hexane as a solvent, As a chain transfer agent, 0.06 g of ethylene glycol monomethyl ether was charged, and 195 g of ethylene oxide was sequentially added while monitoring the polymerization rate of glycidyl methacrylate by gas chromatography. The polymerization reaction was stopped with methanol. The polymer was taken out by decantation and then dried at 40 ° C. under normal pressure for 24 hours and further at 45 ° C. for 10 hours under reduced pressure to obtain 223 g of polymer.

[Polymerization Example 6]
The same procedure as in Polymerization Example 5 was carried out except that 30 g of allyl glycidyl ether, 100 g of ethylene oxide, and 0.02 g of n-butanol were polymerized to obtain 125 g of polymer.

[Polymerization Example 7]
The same operation as in Polymerization Example 5 was carried out except that 30 g of glycidyl methacrylate, 260 g of ethylene oxide, and 0.08 g of ethylene glycol monomethyl ether were polymerized to obtain 252 g of polymer.

[Example 1] Production of capacitor composed of negative electrode / electrolyte composition 1 / positive electrode <Production of negative electrode 1>
As a negative electrode active material, 100 parts by weight of graphite having a volume average particle diameter of 4 μm, 1.5% aqueous solution of sodium carboxymethylcellulose having a molecular weight of 30,000 (manufactured by Daicel Chemical Industries, Ltd.), 2 parts by weight corresponding to the solid content, conductive As an auxiliary, 5 parts by weight of acetylene black, 3 parts by weight of a 40% aqueous dispersion of an SBR binder having a number average particle size of 0.15 μm corresponding to the solid content, and 35% of the total solid content concentration of ion-exchanged water The electrode coating solution for the negative electrode was prepared by mixing and dispersing in the above.

  The electrode coating solution for the negative electrode was applied onto a copper foil having a thickness of 18 μm by a doctor blade method, temporarily dried, and then cut so that the electrode size was 20 mm × 30 mm. The electrode thickness was about 50 μm. Before assembling the cell, it was dried in vacuum at 120 ° C. for 5 hours.

<Lithium doping to the negative electrode>
The negative electrode obtained as described above was doped with lithium as follows. The negative electrode and lithium metal foil were sandwiched between separators (polypropylene nonwoven fabric) and set in a beaker cell, and a predetermined amount of lithium ions was occluded in the negative electrode over about 10 hours. The amount of lithium doped was about 75% of the negative electrode capacity.

<Preparation of positive electrode 1>
As the positive electrode active material, activated carbon powder having a volume average particle diameter of 8 μm, which is an alkali activated activated carbon made of phenol resin as a raw material, was used. Based on 100 parts by weight of the positive electrode active material, a 1.5% aqueous solution of sodium carboxymethylcellulose having a molecular weight of 30,000 (manufactured by Daicel Chemical Industries, Ltd.) as a dispersant is 2 parts by weight corresponding to the solid content, and acetylene is used as a conductive assistant. 5 parts by weight of black, 3% by weight of a 40% aqueous dispersion of SBR binder having a number average particle size of 0.15 μm as a binder, and a total solid content of ion exchange water of 30% An electrode coating solution for the positive electrode was prepared by mixing and dispersing using a disperser.

  This electrode coating solution for the positive electrode was applied onto a 30 μm-thick aluminum foil perforated current collector by the doctor blade method, temporarily dried, and then cut so that the electrode size was 20 mm × 30 mm. The electrode thickness was about 50 μm.

<Preparation of electrolyte composition 1>
10 parts by weight of the copolymer obtained in Polymerization Example 1, 1 part by weight of trimethylolpropane trimethacrylate, and 0.1 part by weight of t-butylperoxy-2-ethylhexanoate were mixed with 1-ethyl-3-methylimidazo. Electrolyte composition 1 was prepared by dissolving in 90 parts by weight of a solution prepared by dissolving lithium borofluoride in a concentration of 1 mol / L in lithium tetrafluoroborate.

<Assembly of capacitor cell>
The electrolyte composition 1 was injected between the negative electrode and the positive electrode for a lithium ion capacitor. Thereafter, the mixture was reacted at 90 ° C. for 7 hours for crosslinking to produce a laminated cell-shaped lithium ion capacitor. The completed cell was left as it was for about 1 day until measurement.

[Example 2] Production of capacitor composed of negative electrode / electrolyte composition 2 / positive electrode Production of a negative electrode and a positive electrode was carried out in the same manner as in Example 1.

<Preparation of electrolyte composition 2>
10 parts by weight of the copolymer obtained in Polymerization Example 2, 1 part by weight of trimethylolpropane trimethacrylate, and 0.1 part by weight of t-butylperoxy-2-ethylhexanoate were added to 1-ethyl-3-methylimidazo. Electrolyte composition 2 was prepared by dissolving in 90 parts by weight of a solution in which lithium borofluoride was dissolved in 1 mol / L of lithium = tetrafluoroborate.

<Assembly of capacitor cell>
The electrolyte composition 2 was injected between the negative electrode and the positive electrode for a lithium ion capacitor. Thereafter, the mixture was reacted at 90 ° C. for 7 hours for crosslinking to produce a laminated cell-shaped lithium ion capacitor. The completed cell was left as it was for about 1 day until measurement.

[Example 3] Production of capacitor composed of negative electrode / electrolyte composition 3 / positive electrode Production of a negative electrode and a positive electrode was carried out in the same manner as in Example 1.

<Preparation of electrolyte composition 3>
10 parts by weight of the copolymer obtained in Polymerization Example 3, 1 part by weight of trimethylolpropane trimethacrylate, 0.1 part by weight of t-butylperoxy-2-ethylhexanoate was added to 1-ethyl-3-methylimidazo. Electrolyte composition 3 was prepared by dissolving in 90 parts by weight of a solution in which lithium borofluoride was dissolved in 1 mol / L in lithium = tetrafluoroborate.

<Assembly of capacitor cell>
The electrolyte composition 3 was injected between the negative electrode and the positive electrode for a lithium ion capacitor. Thereafter, the mixture was reacted at 90 ° C. for 7 hours for crosslinking to produce a laminated cell-shaped lithium ion capacitor. The completed cell was left as it was for about 1 day until measurement.

[Example 4] Production of capacitor composed of negative electrode / electrolyte composition 4 / positive electrode Production of a negative electrode and a positive electrode was carried out in the same manner as in Example 1.

<Preparation of electrolyte composition 4>
10 parts by weight of the copolymer obtained in Polymerization Example 4, 0.1 part by weight of the photoinitiator benzophenone in 1-ethyl-3-methylimidazolium tetrafluoroborate and lithium borofluoride at a concentration of 1 mol / L. Electrolyte composition 4 was prepared by dissolving in 90 parts by weight of the dissolved solution.

<Formation of electrolyte composition layer>
On the positive electrode sheet obtained in Example 1, the electrolyte composition 4 was applied with a doctor blade to form an electrolyte composition layer having a thickness of 50 μm. Then, after drying, in a state where the electrolyte surface is covered with a laminate film, crosslinking is performed by irradiating with a high pressure mercury lamp (30 mW / cm ² ) manufactured by GS Yuasa Co., Ltd. for 30 seconds, and the electrolyte composition is formed on the positive electrode sheet. A positive electrode / electrolyte sheet in which the layers were integrated was prepared.

<Assembly of capacitor cell>
The positive electrode / electrolyte sheet and the negative electrode were bonded together in a glove box substituted with argon gas, and the whole was covered with a laminate film to produce a laminated cell-shaped lithium ion capacitor. The completed cell was left as it was for about 1 day until measurement.

[Example 5] Production of capacitor composed of negative electrode / electrolyte composition 5 / positive electrode Production of a negative electrode and a positive electrode was carried out in the same manner as in Example 1.

<Preparation of electrolyte composition 5>
10 parts by weight of the copolymer obtained in Polymerization Example 5, 0.05 part by weight of photoinitiator benzophenone in 1-ethyl-3-methylimidazolium tetrafluoroborate and lithium borofluoride at a concentration of 1 mol / L Electrolyte composition 5 was prepared by dissolving in 90 parts by weight of the dissolved solution.

<Formation of electrolyte composition layer>
On the positive electrode sheet obtained in Example 1, the electrolyte composition 5 was applied with a doctor blade to form an electrolyte composition layer having a thickness of 50 μm. Then, after drying, in a state where the electrolyte surface is covered with a laminate film, crosslinking is performed by irradiating with a high pressure mercury lamp (30 mW / cm ² ) manufactured by GS Yuasa Co., Ltd. for 30 seconds, and the electrolyte composition is formed on the positive electrode sheet. A positive electrode / electrolyte sheet in which the layers were integrated was prepared.

<Assembly of capacitor cell>
The positive electrode / electrolyte sheet and the negative electrode were bonded together in a glove box substituted with argon gas, and the whole was covered with a laminate film to produce a laminated cell-shaped lithium ion capacitor. The completed cell was left as it was for about 1 day until measurement.

[Example 6] Production of capacitor composed of negative electrode / electrolyte composition 6 / positive electrode Production of a negative electrode and a positive electrode was carried out in the same manner as in Example 1.

<Preparation of electrolyte composition 6>
10 parts by weight of the copolymer obtained in Polymerization Example 6, 1 part by weight of trimethylolpropane trimethacrylate, 0.1 part by weight of t-butylperoxy-2-ethylhexanoate was added to 1-ethyl-3-methylimidazo. Electrolyte composition 6 was prepared by dissolving 90 parts by weight of a solution in which lithium borofluoride was dissolved in a concentration of 1 mol / L in lithium = tetrafluoroborate.

<Formation of electrolyte composition layer>
On the positive electrode sheet obtained in Example 1, the electrolyte composition 6 was applied with a doctor blade to form an electrolyte composition layer having a thickness of 50 μm. Then, after drying, in a state where the electrolyte surface was covered with a laminate film, the mixture was reacted and crosslinked at 90 ° C. for 7 hours to prepare a positive electrode / electrolyte sheet.

<Assembly of capacitor cell>
The positive electrode / electrolyte sheet and the negative electrode were bonded together in a glove box substituted with argon gas, and the whole was covered with a laminate film to produce a laminated cell-shaped lithium ion capacitor. The completed cell was left as it was for about 1 day until measurement.

[Example 7] Production of capacitor composed of negative electrode / electrolyte composition 7 / positive electrode Production of a negative electrode and a positive electrode was carried out in the same manner as in Example 1.

<Preparation of electrolyte composition 7>
10 parts by weight of the copolymer obtained in Polymerization Example 7, 0.05 part by weight of the photoinitiator benzophenone in 1-ethyl-3-methylimidazolium tetrafluoroborate and lithium borofluoride at a concentration of 1 mol / L Electrolyte composition 7 was prepared by dissolving in 90 parts by weight of the dissolved solution.

<Formation of electrolyte composition layer>
On the positive electrode sheet obtained in Example 1, the electrolyte composition 7 was applied with a doctor blade to form an electrolyte composition layer having a thickness of 50 μm. Then, after drying, in a state where the electrolyte surface is covered with a laminate film, crosslinking is performed by irradiating with a high pressure mercury lamp (30 mW / cm ² ) manufactured by GS Yuasa Co., Ltd. for 30 seconds, and the electrolyte composition is formed on the positive electrode sheet. A positive electrode / electrolyte sheet in which the layers were integrated was prepared.

<Assembly of capacitor cell>
The positive electrode / electrolyte sheet and the negative electrode were bonded together in a glove box substituted with argon gas, and the whole was covered with a laminate film to produce a laminated cell-shaped lithium ion capacitor. The completed cell was left as it was for about 1 day until measurement.

Comparative Example 1 Production of Capacitor Constructed of Negative Electrode / Electrolyte Solution 8 / Positive Electrode The negative electrode and the positive electrode were produced in the same manner as in Example 1.

<Preparation of electrolyte solution 8>
Electrolyte solution 8 was prepared by dissolving lithium hexafluorophosphate (LiPF ₆ ) in a mixed solvent of ethylene carbonate and diethyl carbonate in a volume ratio of 4: 6 so as to have a concentration of 1 mol / L.

<Assembly of capacitor cell>
A separator (polypropylene nonwoven fabric) was inserted between the positive electrode and the negative electrode obtained in Example 1, impregnated with the electrolyte solution 8, and sealed in a storage case made of a laminate film. The completed cell was left as it was for about 1 day until measurement.

Comparative Example 2 Production of Capacitor Constructed of Negative Electrode / Electrolyte Composition 9 / Positive Electrode The negative electrode and the positive electrode were produced in the same manner as in Example 1.

<Preparation of electrolyte composition 9>
50 parts by weight of the polyether copolymer obtained in Polymerization Example 1 in acetonitrile (250 parts by weight), 15 parts by weight of propylene carbonate, 7 parts by weight of lithium borofluoride, and 0.75 part by weight of benzoyl oxide as a crosslinking agent did.

<Formation of electrolyte composition layer>
The electrolyte composition 9 was applied on the positive electrode sheet obtained in Example 1. Thereafter, acetonitrile was volatilized, and crosslinking was performed at 100 ° C. for 3 hours while removing the solvent to obtain a sheet of the electrolyte composition 9 crosslinked on the positive electrode sheet. The obtained composite sheet was vacuum-dried at 40 ° C. for 24 hours. In the composite sheet, the thickness of the positive electrode activated carbon layer / electrolyte composition 9 layer was 100 μm, and the weight ratio of the positive electrode activated carbon layer to the electrolyte composition layer was 50/50.

<Assembly of capacitor cell>
Separator (thickness: 100 μm) made of porous polypropylene impregnated with the electrolyte composition 9 and crosslinked between the composite sheet of the positive electrode / electrolyte composition 9 and the negative electrode sheet thus obtained (electrolyte composition) 9 and the weight ratio of porous polypropylene: 50/50), and these were pressure-bonded. This sheet was sealed in a storage case made of a laminate film. The completed cell was left as it was for about 1 day until measurement.

<Electrochemical evaluation of capacitor cell>
The laminate cell was subjected to electrochemical evaluation.

  The discharge capacity was the discharge capacity at the fifth cycle when a constant current was charged to 4.0 V at a predetermined current and a constant current was discharged to 2.0 V at the same current as the charge. The charge / discharge current was set to 1C and 100C with a current (1C) that can discharge the cell capacity in one hour as a reference (1C). In Table 2, the discharge capacity at the fifth cycle measured with a charge / discharge current of 1 C is shown as “discharge capacity”. Further, “discharge capacity maintenance ratio at 100 C relative to 1 C” was calculated by the following formula, and the value is shown in Table 2.

Discharge capacity maintenance ratio (%) at 100 C with respect to 1 C = (discharge capacity at the fifth cycle at 100 C) ÷ (discharge capacity at the fifth cycle at 1 C) × 100
Further, a charge / discharge cycle test was conducted at 10C. In the charge / discharge cycle test, 10C was charged at a constant current up to 4.0V, 10C was discharged at a constant current up to 2.0V, and this was taken as one cycle, and 10,000 cycles were charged / discharged. The discharge capacity after 10,000 cycles with respect to the initial discharge capacity is shown in Table 2 as the capacity retention rate.

  All measurements were performed at 25 ° C.

  In Table 2, in Examples 1 to 7, the discharge capacity is high, the discharge capacity maintenance rate at 100 C is high, and the capacity maintenance rate after 10,000 cycles is also high. This is presumably because stable characteristics can be obtained without a separator.

  The electrochemical capacitor of the present invention has a high capacity and excellent charge / discharge characteristics, and is excellent in safety and reliability. Therefore, the electrochemical capacitor can be used as a small capacitor for a mobile phone or a notebook personal computer, as a large capacitor for stationary type or in-vehicle use. Can be used.

Claims (7)

At least a negative electrode,
Formula (1):
[Wherein, R represents an alkyl group having 1 to 12 carbon atoms, or —CH ₂ O (CR ¹ R ² R ³ ). R ¹ , R ² and R ³ are hydrogen atoms or —CH ₂ O (CH ₂ CH ₂ O) _n R ⁴ , and n and R ⁴ may be different among R ¹ , R ² and R ^3. . R ⁴ is an alkyl group having 1 to 12 carbon atoms or an aryl group which may have a substituent, and n is an integer of 0 to 12. And 0 to 70 mol% of repeating units derived from the monomer represented by formula (2):
A polyether copolymer or a cross-linked product thereof and an electrolyte salt compound containing 97 to 10 mol% of repeating units derived from the monomer represented by formula (1) and 3 to 15 mol% of repeating units derived from glycidyl methacrylate An electrochemical capacitor comprising: an electrolyte composition that does not contain a crosslinking aid , and a positive electrode; and no separator is used.   The electrochemical capacitor according to claim 1, wherein the electrolyte composition contains an aprotic organic solvent or a room temperature molten salt.   The electrochemical capacitor according to claim 1 or 2, wherein the negative electrode has a mixture of a negative electrode active material, a conductive additive, and a binder, and the negative electrode active material is graphite or activated carbon.   The electrochemical capacitor according to claim 3, wherein the negative electrode is doped with lithium.   The electrochemical capacitor according to any one of claims 1 to 4, wherein the positive electrode has a mixture of a positive electrode active material, a conductive additive, and a binder, and the positive electrode active material is activated carbon.   The electrochemical capacitor according to claim 1, wherein the polyether copolymer has a weight average molecular weight of 100,000 to 1.8 million. The electrochemical capacitor according to any one of claims 1 to 6, wherein the electrolyte composition contains a photoreaction initiator.