JP3315807B2 - Electric double layer capacitor and method of manufacturing the same - Google Patents

Abstract

PURPOSE:To obtain a highly reliable electric double layer capacitor having high decomposition voltage and low inner resistance in which leakage of electrolyte is prevented. CONSTITUTION:Positive and negative electrodes 1, 2 are formed of active carbon particles and a composite gel prepared by sol-gel method using silica gel and sulfuric acid. Current collecting layers 3, 4 are then formed on one sides thereof by plasma spraying stainless steel. The positive and negative electrodes 1, 2 are then opposed each other through an electrolyte 5 employing the composite gel. The upper member 6 (sealing plate) and a lower members 7(case) of the casing are then caulked through a polypropylene packing 8 thus constituting a coin type electric double layer capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an all-solid-state, small-capacity, large-capacity electric double layer capacitor and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, electric double layer capacitors have been widely used as small power supplies for backing up semiconductor memories. There is a need for a more reliable capacitor that does not leak electrolyte and has less self-discharge.

[0003] Conventional techniques in this field include:
(A) A capacitor using a polycrystalline solid electrolyte having metal ion conductivity as an electrolyte is disclosed in
There is a proposal in Japanese Patent Application Laid-Open No. 3-61053. This capacitor uses a solid electrolyte having copper ion conductivity as an electrolyte.

Further, (B) an organic solvent in which an electrochemically stable electrolyte is dissolved is used as an electrolytic solution, and activated carbon powder is used as a polarizable electrode, for example, as disclosed in JP-A-49-682.
There has been proposed in Japanese Patent Application Publication No. 54-54. This capacitor uses an organic electrolyte obtained by dissolving a tetraalkylammonium perchlorate in an organic solvent such as propylene carbonate.

[0005]

In the electric double layer capacitor having the above structure, when a polycrystalline solid electrolyte having metal ion conductivity as described in the above (A) is used, the electric double layer capacitor has a large capacity. Since the decomposition voltage of the crystalline solid electrolyte is low (0.6 V or less), it is difficult to increase the withstand voltage of the capacitor. Further, since the electric conductivity of the solid electrolyte is not sufficiently high, the discharge characteristics of the internal resistance are small. There is a problem that it is difficult to obtain an excellent capacitor.

Further, when an organic electrolyte as described in the above (B) is used, it is difficult to completely prevent leakage of the electrolyte, and a capacitor having high reliability in a wide temperature range is required. There was a problem that it was difficult to manufacture.

An object of the present invention is to provide a highly reliable electric double layer capacitor having a higher decomposition voltage, a smaller internal resistance, and no liquid leakage, and a method of manufacturing the same, in order to solve the above-mentioned problems. I do.

[0008]

In order to achieve the above object, an electric double layer capacitor of the present invention comprises a polarizable electrode on the positive electrode side and a negative electrode side through an electrolyte using a composite gel comprising a dopant and a matrix gel. The polarizable electrodes are opposed to each other, each polarizable electrode is provided with a current collector made of a metal or a conductive resin, and activated carbon is used for the positive and negative polarizable electrodes.

In the above structure, the matrix gel is preferably at least one selected from silica gel, alumina gel, and titania gel. Next, the first method for producing an electric double layer capacitor of the present invention is to produce a composite gel as an electrolyte by hydrolyzing a mixed sol comprising a dopant and a metal alkoxide, and to form a composite gel produced from the mixed sol. Activated carbon is mixed to form a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side, a current collector made of a metal or a conductive resin is formed on each of the polarizable electrodes, and the positive electrode side is interposed through the electrolyte. And a polarizable electrode on the negative electrode side are provided so as to face each other.

In a second method of manufacturing an electric double layer capacitor according to the present invention, a composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant and a metal alkoxide, and the composite gel is prepared from the dopant, the metal alkoxide and the activated carbon. Forming a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side by hydrolyzing the mixed sol, forming a current collector made of a metal or a conductive resin on each of the polarizable electrodes, A configuration is provided in which the polarizable electrode on the positive electrode side and the polarizable electrode on the negative electrode side are provided so as to be opposed to each other.

A third method of manufacturing an electric double layer capacitor according to the present invention is characterized in that a mixed sol comprising a dopant and a metal alkoxide is hydrolyzed to produce a composite gel as an electrolyte, and the composite gel produced from the mixed sol is produced. The activated carbon and the binder are mixed into the gel to form a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side, and each of the polarizable electrodes is press-formed together with a current collector made of a metal or a conductive resin, and the electrolyte is formed. And the polarizable electrode on the positive electrode side and the polarizable electrode on the negative electrode side are provided so as to face each other.

In the first, second or third production method, the mixed sol may further contain at least one organic compound selected from ethylene carbonate, propylene carbonate, gamma-butyl lactone, dimethylformamide, and dimethyl sulfoxide. It is preferred to add a solvent.

A fourth method for manufacturing an electric double layer capacitor according to the present invention is a method for producing a composite gel as an electrolyte by hydrolyzing a mixed sol comprising a dopant, a metal alkoxide and an organic solvent, and producing the composite gel from the mixed sol. After mixing the prepared composite gel, activated carbon and a binder, the mixture was applied to a metal current collector to form a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side, and the polarizable electrode on the positive electrode side via the electrolyte. And a polarizable electrode on the negative electrode side are provided facing each other.

A fifth method for manufacturing an electric double layer capacitor according to the present invention is directed to a method for manufacturing a positive electrode by dipping a metal current collector in a mixed sol comprising a dopant, a metal alkoxide, an organic solvent and activated carbon and hydrolyzing the sol. Forming a polarizable electrode on the negative electrode side and a polarizable electrode on the negative electrode side, and preparing a composite gel as an electrolyte by applying a mixed sol comprising a dopant, a metal alkoxide and an organic solvent to each of the polarizable electrodes and hydrolyzing the mixed sol. The polarizable electrode on the positive electrode side and the polarizable electrode on the negative electrode side are provided so as to face each other with the electrolyte interposed therebetween.

[0015] In a sixth method of manufacturing an electric double layer capacitor according to the present invention, after forming a metal current collector layer on an activated carbon fiber cloth, the activated carbon fiber cloth is mixed with a mixed sol comprising a dopant, a metal alkoxide and an organic solvent. A polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side are formed by immersion in and hydrolysis, and the mixed sol is applied to each of the polarizable electrodes and hydrolyzed to produce a composite gel as an electrolyte. In addition, a configuration is provided in which the polarizable electrode on the positive electrode side and the polarizable electrode on the negative electrode side are provided so as to face each other via the electrolyte.

In the first to sixth manufacturing methods,
It is preferable to further mix graphite fine particles into the mixed sol used for the polarizable electrode. Further, in the electric double layer capacitor of the present invention or the first to sixth methods for producing the same, the dopant is hydrochloric acid, sulfuric acid, heteropoly acid, perchloric acid, acid or alkali of potassium hydroxide, tetraethylammonium perchlorate, And at least one selected from tetraethylammonium borofluoride.

Further, in the electric double layer capacitor of the present invention or the first to sixth methods for producing the same, the activated carbon is formed from phenol-based, pitch-based, and polyacrylonitrile (PAN) -based powdered or fibrous activated carbon. Preferably, at least one selected from them is used.

In the electric double layer capacitor of the present invention or the first to sixth methods for producing the same, the metal used for the current collector is preferably at least one selected from aluminum, titanium and stainless steel. .

In the fourth to sixth production methods of the present invention, the organic solvent is at least one selected from ethylene carbonate, propylene carbonate, gamma-butyl lactone, dimethylformamide and dimethyl sulfoxide. Is preferred.

[0020]

According to the electric double layer capacitor of the present invention,
A polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side are opposed to each other via an electrolyte using a composite gel composed of a dopant and a matrix gel, and each polarizable electrode is provided with a current collector made of a metal or a conductive resin. And, by using activated carbon for the polarizable electrodes on the positive electrode side and the negative electrode side, since the electric double layer capacity formed at the interface between the electrolyte ion and the activated carbon of the composite gel is used, the part degraded by the electrochemical reaction is reduced. In addition, the decomposition voltage is relatively high, the internal resistance can be reduced, and since the electrolyte is in a gel state, a highly reliable electric double layer capacitor free of liquid leakage can be provided.

Further, according to the preferred configuration of the present invention in which the matrix gel is at least one selected from silica gel, alumina gel and titania gel, the chemical stability of the electric double layer capacitor is improved.

Next, according to the first production method, a composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant and a metal alkoxide, and activated carbon is added to the composite gel produced from the mixed sol. Mixing to form a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side, forming a current collector made of a metal or a conductive resin on each of the polarizable electrodes, and separating the collector on the positive electrode side through the electrolyte By providing the polar electrode and the polarizable electrode on the negative electrode side to face each other, a polarizable electrode having a uniform composition can be obtained, and an electric double layer capacitor without electrolyte leakage can be manufactured.

According to the second production method, a composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant and a metal alkoxide, and a mixed sol comprising a dopant, a metal alkoxide and activated carbon is hydrolyzed. By forming a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side by decomposition, a current collector made of a metal or a conductive resin is formed on each of the polarizable electrodes, and the positive electrode side is interposed through the electrolyte. The polarizable electrode having a uniform composition can be obtained by providing the polarizable electrode and the polarizable electrode on the negative electrode side opposite to each other, and an electric double layer capacitor free of electrolyte leakage can be manufactured.

Further, according to the third manufacturing method, a composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant and a metal alkoxide, and activated carbon and binding are added to the composite gel produced from the mixed sol. A positive electrode-side polarizable electrode and a negative electrode-side polarizable electrode are mixed with each other, and each of the polarizable electrodes is press-formed with a current collector made of a metal or a conductive resin, and the positive electrode is interposed through the electrolyte. By providing the polarizable electrode on the negative electrode side and the polarizable electrode on the negative electrode side opposite to each other, a polarizable electrode having a uniform composition can be obtained, and an electric double layer capacitor without electrolyte leakage can be easily manufactured. it can.

In the first, second or third production method, the mixed sol may further contain at least one organic solvent selected from ethylene carbonate, propylene carbonate, gamma-butyl lactone, dimethylformamide, and dimethyl sulfoxide. According to a preferred configuration of the present invention in which the organic solvent is added, these organic solvents have a boiling point of 2
It is convenient because it is chemically stable as high as 00 ° C. or higher.

According to the fourth production method, a composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant, a metal alkoxide and an organic solvent, After mixing the activated carbon and the binder, the mixture is applied to a metal current collector to form a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side, and the polarizable electrode on the positive electrode side and the negative electrode side are separated via the electrolyte. By providing the polar electrodes facing each other, the composite gel, the activated carbon and the mixture of the binder can be held on the metal current collector, so that a positive electrode and a negative electrode having a uniform composition are obtained, and the internal resistance of the current collector is excellent. A small, highly reliable electric double layer capacitor can be manufactured.

Further, according to the fifth manufacturing method, a metal current collector is immersed in a mixed sol comprising a dopant, a metal alkoxide, an organic solvent and activated carbon, and the sol is hydrolyzed. A polarizable electrode on the negative electrode side is formed, and a mixed sol comprising a dopant, a metal alkoxide, and an organic solvent is applied to each of the polarizable electrodes and hydrolyzed to produce a composite gel as an electrolyte, via the electrolyte. By providing the polarizable electrode on the positive electrode side and the polarizable electrode on the negative electrode side opposite to each other, the composite sol can be held on the metal current collector, so that a positive electrode and a negative electrode having a uniform composition can be obtained, A highly reliable electric double layer capacitor with excellent internal resistance and low internal resistance can be manufactured.

According to the sixth manufacturing method, after forming the metal current collector layer on the activated carbon fiber cloth, the activated carbon fiber cloth is immersed in a mixed sol comprising a dopant, a metal alkoxide and an organic solvent to hydrolyze. To form a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side, to prepare a composite gel as an electrolyte by applying the mixed sol to each of the polarizable electrodes and hydrolyzing it, By providing the polarizable electrode on the positive electrode side and the polarizable electrode on the negative electrode side through the composite gel, the composite gel can be held on the metal current collector, so that a positive electrode and a negative electrode having a uniform composition can be obtained. It is possible to manufacture a highly reliable electric double layer capacitor having excellent internal performance and small internal resistance.

In the first to sixth manufacturing methods, according to a preferred configuration of the present invention in which graphite fine particles are further mixed with the mixed sol used for the polarizable electrode, the polarizable electrode is added by adding the graphite fine particles. Therefore, an electric double layer capacitor having a small internal resistance and high reliability can be manufactured.

Further, in the electric double layer capacitor of the present invention or the first to sixth manufacturing methods thereof, the dopant is an acid or alkali of hydrochloric acid, sulfuric acid, heteropoly acid, perchloric acid, potassium hydroxide, tetraethyl perchlorate. According to the preferred configuration of the present invention, which is at least one selected from ammonium and tetraethylammonium borofluoride, the electric conductivity can be increased in an acid or alkali solution, and the internal resistance of the capacitor can be reduced. An organic electrolyte using an electrolyte salt such as tetraethylammonium chlorate or tetraethylammonium borofluoride has a high decomposition voltage and can increase the withstand voltage of the capacitor.

In the electric double layer capacitor of the present invention or the first to sixth methods for producing the same, the activated carbon is selected from powdered or fibrous activated carbon of phenol type, pitch type and polyacrylonitrile (PAN) type. According to a preferred configuration of the present invention, the activated carbon has a specific surface area of at least 2000 m ² g ^-1 which is at least twice as large as that of coconut shell charcoal, and has a pore diameter of 2 to 4 nm. And the double layer capacity can be increased.

Further, in the electric double layer capacitor of the present invention or the first to sixth methods for producing the same, the metal used for the current collector is at least one selected from aluminum, titanium and stainless steel. According to the preferred configuration, the electrochemical stability of the polarizable electrode, particularly the positive electrode, is improved.

In the fourth to sixth production methods of the present invention, the organic solvent is at least one selected from ethylene carbonate, propylene carbonate, gamma-butyl lactone, dimethylformamide and dimethyl sulfoxide. According to the preferred configuration, these organic solvents are convenient because they have a high boiling point of 200 ° C. or higher and are chemically stable.

[0034]

EXAMPLES In this example, a gel matrix produced by hydrolysis of metal alkoxide (so-called sol-gel method) is preferably chemically and physically stable silica gel, alumina gel or titania gel.

The sol-gel method is a method in which a lower alkoxide of a sol-like metal is hydrolyzed, gelled, and heated to obtain glass or ceramics.
Specific examples of typical metal alkoxides include lower alkoxides of silicon such as methoxide and ethoxide of silicon, lower alkoxides of aluminum such as methoxide and ethoxide of aluminum, and lower alkoxides of titanium such as methoxide and ethoxide of titanium. There is kind. Water and / or methanol, ethanol, propanol or ethylene glycol of a dihydric alcohol is used as a dispersion medium of the sol, and hydrochloric acid or ammonia is usually used as a hydrolysis catalyst.

Further, formamide or dimethylformamide may be used as a drying control agent for preventing the generation of cracks and foaming that occur when the gel is dried. In this embodiment, the amount of dopant used is 0.0
It is preferably about 3 to 2.00.

In the present embodiment, the gelation reaction temperature is usually preferably in the range of room temperature to 80 ° C. for a system containing an aqueous solution, and is preferably in the range of 100 to 130 ° C. for a system containing an organic solvent. As the form of the gel used in the present embodiment, a bulk form containing an electrolyte or activated carbon is preferable. Further, as another form, fine particles are preferable, and more specifically, a particle diameter of 0.5 to 200 μm is preferable. Further, as another embodiment, a thin film is preferable, and more specifically, a film having a thickness of about 0.1 to 3 μm is preferable.

The activated carbon used as the polarizable electrode in this embodiment is not particularly limited, and various types of activated carbon can be used. The form of the activated carbon is preferably in the form of fine particles, and more specifically, in the form of activated carbon. It is also preferable to use a fibrous material. In particular, phenol-based, pitch-based, and polyacrylonitrile (PAN) -based powdered or fibrous activated carbon has a specific surface area of at least 2,000 m ^{2 which is at} least twice that of coconut shell charcoal.
g ⁻¹ , and the pore diameter can be controlled in the range of 2 to 4 nm.
The addition amount is preferably 30 to 80 wt% based on the composite gel.

The fine graphite particles used in this embodiment preferably have a submicron particle size. The addition amount is preferably 5 to 10% by weight based on the composite sol. The metal current collector used in this embodiment is preferably aluminum, titanium, stainless steel, or the like, which is electrochemically stable at the positive electrode, and is preferably in the form of a mesh or a fiber cloth. As the current collector made of a conductive resin, it is preferable to use a paste or thin film of graphite / acrylic resin or graphite / polyethylene resin in which graphite is dispersed.

As the binder used in the present embodiment, polyvinyl alcohol, fluororesin, or the like can be used, but a fluororesin having a strong binding force and being chemically stable, such as ethylene tetrafluoride resin, is particularly preferable. The addition amount is preferably 0.1 to 5% by weight based on the mixture containing the gel.

The activated carbon fiber cloth used in this embodiment is obtained by carbonizing and activating a cloth-like raw material resin to activate carbonization.
Hereinafter, specific examples will be described.

Example 1 Production of Composite Gel as Electrolyte
The starting composition is a molar ratio of Si (OEt)_Four, Ethanor
Water, sulfuric acid (dopant) at 1: 5: 10: 0.1
Stir at room temperature for 30 minutes and gel at a temperature of 60 ° C.
Was. The electrical conductivity of this gel is 4 × 10 ^-1Scm^-1
Met. The gel produced in this way is crushed and
Fine particles having a diameter of 30 μm were obtained. 3to using these fine particles
ncm^TwoPressed with pressure of 10mm in diameter, thickness
A 0.3 mm tablet was prepared and used as an electrolyte.

The polarizable electrode has a specific surface area of 200.
0 m ² g ^-1 phenolic activated carbon particles (average particle size 20 μm)
m) was used. In order to reduce the contact resistance between the composite gel fine particles and the activated carbon particles, 50
The mixture mixed at a weight ratio of 50 to 50 was press-formed at a pressure of 3 ton · cm ² to obtain a tablet having a diameter of 10 mm and a thickness of 1 mm. Further, one side of the positive electrode and the negative electrode is made of stainless steel by plasma spraying to a thickness of 100 μm.
Was formed.

A coin-type electric double layer capacitor is constructed using the tablet-shaped positive electrode, negative electrode, and electrolyte thus produced, and a schematic cross-sectional view thereof is shown in FIG. In FIG. 1, 1 is a positive electrode, 2 is a negative electrode, 3 and 4 are current collecting layers, 5
Is an electrolyte, 6 is an upper member, 7 is a lower member, and 8 is a packing.

The positive electrode 1 and the negative electrode 2 are opposed to each other with the electrolyte 5 interposed therebetween, and pressed at a pressure of 100 Kgcm ⁻² .
As shown in FIG. 1, the electrolyte 5, the positive electrode 1 and the negative electrode 2 are arranged, and the upper member 6 (sealing plate) and the lower member 7 of the casing.
(Case) was sealed by caulking through a packing 8 made of polypropylene. Stainless steel was used as a constituent material of the upper member 6 and the lower member 7. In all the other embodiments described below, the structure of the capacitor is the same as that shown in FIG. 1, and the upper member 6, the lower member 7 (case), and the packing 8 are the same as those in this embodiment. Was.

After charging the capacitor of this example at 0.8 V, it was discharged at a constant current of 10 μA to obtain a capacity of 0.5 F and an impedance of 8 ohms. Also, always at 0.
When 8 V was applied, the capacity reduction ratio after 1000 hours with respect to the initial capacity was 11%. In addition, no leakage of the electrolyte solution was observed in the samples subjected to the experiment. Other hydrochloric acid,
Capacitors exhibiting substantially the same characteristics as described above could be produced even using an acid of heteropolyacid, perchloric acid, potassium hydroxide or an alkaline electrolyte. When a conductive resin made of graphite / acrylic resin is used for the current collecting layer,
Although the impedance increased to 21 ohms, the reliability was almost the same as that of this embodiment.

Further, even when pitch-based or polyacrylonitrile (PAN) -based activated carbon particles were used instead of the phenol-based activated carbon particles, the characteristics were almost the same as those of the capacitor of this embodiment.

Further, a capacitor having the same characteristics as those of the present example could be produced by using an alumina or titania gel using aluminum ethoxide or titanium ethoxide other than silicon ethoxide.

Further, even when the electrolyte 5 was used while being held on a polypropylene separator having a thickness of 70 μm, a capacitor having substantially the same characteristics as those of the present example could be produced.
On the other hand, the initial characteristics of a coin-type capacitor having a similar structure using conventional sulfuric acid as the electrolyte were almost the same as those of the present embodiment, but when a constant voltage of 0.8 V was applied in an atmosphere of 70 ° C., the initial capacity was 1000%. 23% capacity reduction after time
Met. Also, in the sample subjected to the experiment, leakage of the electrolytic solution was observed in 5%.

Example 2 As a starting composition of a composite gel as an electrolyte, a molar ratio of Si (OEt) ₄ , ethanol, water, propylene carbonate and tetraethylammonium perchlorate (dopant) was 1: 5: 1: 1. : 0.
The mixture was stirred at room temperature for 30 minutes using No. 1 and gelled at a temperature of 60 ° C. Further, the gel was heated at 110 ° C. to evaporate water. The electrical conductivity of this gel is 6 × 10 ⁻⁴ Scm ⁻¹ at room temperature.
Met. The gel thus produced was pulverized into fine particles having an average particle size of 30 μm. 3to using these fine particles
It was press-molded under a pressure of n · cm ² to produce a tablet having a diameter of 10 mm and a thickness of 0.3 mm, which was used as an electrolyte 5.

The polarizable electrode has a specific surface area of 200.
0 m ² g ^-1 phenolic activated carbon particles (average particle size 20 μm)
m) was used. In order to reduce the contact resistance between the composite gel and the activated carbon particles, the positive electrode and the negative electrode were press-formed at a pressure of 3 ton · cm ² in advance by mixing them at a weight ratio of 50 to 50, and the diameter was 10 mm and the thickness was 10 mm. It was made into a 1 mm tablet shape. Such mixing and pressing steps were performed in a dry atmosphere. Further, current collector layers 3 and 4 made of aluminum and having a thickness of 100 μm were formed on one surface of the positive electrode and the negative electrode by plasma spraying.

Using the tablet-shaped positive electrode 1, negative electrode 2, and electrolyte 5 thus produced, a coin-type electric double-layer capacitor having the same configuration as in Example 1 was produced. A series of steps for producing the capacitor was performed in a dry atmosphere.

After charging this capacitor at 2.8 V, 10
Constant current discharge at μA, capacity 0.21F, impedance 2
You got 2 ohms. 2.8 V at 70 ° C
Was applied, the capacity reduction rate after 1000 hours with respect to the initial capacity was 12%. In addition, no leakage of the electrolyte solution was observed in the samples subjected to the experiment. The present embodiment can also be carried out using a possible combination system of an organic solvent such as ethylene carbonate, gamma-butyl lactone, dimethylformamide or dimethyl sulfoxide and an electrolyte salt such as tetraethylammonium perchlorate or tetraethylammonium borofluoride. Capacitors exhibiting substantially the same characteristics as those described above were produced.

When a conductive resin made of graphite / acrylic resin is used for the current collecting layer, the impedance becomes 39%.
Although it became larger in ohms, the reliability was almost the same as that of this embodiment.

Further, even when pitch-based or polyacrylonitrile (PAN) -based activated carbon particles were used in place of the phenol-based activated carbon particles, characteristics substantially equivalent to those of the capacitor of this embodiment were exhibited.

Further, a capacitor having the same characteristics as those of the present example could be manufactured by using an alumina or titania gel using aluminum ethoxide or titanium ethoxide other than silicon ethoxide.

Further, even when the electrolyte 5 was used while being held on a polypropylene separator having a thickness of 70 μm, a capacitor having substantially the same characteristics as those of the present example could be produced.
On the other hand, the initial characteristics of a coin-type capacitor having a similar structure using a conventional electrolytic solution composed of tetraethylammonium perchlorate and propylene carbonate were almost the same as those of the present embodiment, but were always kept at 70 ° C. in an atmosphere. When 2.8 V was applied, the capacity decrease after 1000 hours with respect to the initial capacity was 29%. In addition, 2
% Of the electrolyte solution leaked.

Example 3 As a starting composition of a composite gel as an electrolyte, a molar ratio of Si (OEt) ₄ , ethanol, water, propylene carbonate and tetraethylammonium perchlorate (dopant) was 1: 5: 1: 1. : 0.
Using No. 1, the mixture was stirred at room temperature for 30 minutes and gelled at a temperature of 60 ° C. The gel thus produced was pulverized into fine particles having an average particle size of 30 μm. 3ton using these fine particles
-Press-molding was performed at a pressure of cm ² to produce a tablet having a diameter of 10 mm and a thickness of 0.3 mm, which was used as an electrolyte 5.

Separately from the above composite gel, 10% by weight of graphite fine particles (average particle size 0.5 μm) based on the above sol mixture
Was added, stirred at room temperature for 30 minutes, and gelled at a temperature of 60 ° C. Further, the gel was heated at 110 ° C. to evaporate water. The electrical conductivity of this gel is 1 × 10 ⁻⁴ Scm at room temperature.
It was ^-1 . The gel thus produced is pulverized into fine particles having an average particle size of 30 μm, and has a specific surface area of 2000 m ² g.
^-1 phenol-based activated carbon particles (average particle size: 20 μm) were mixed at a weight ratio of 30:70 to form a polarizable electrode. The positive electrode and the negative electrode were press-molded at a pressure of 3 toncm ² to previously mix the electrolyte and the activated carbon particles, which are polarizable electrodes, at a weight ratio of 50 to 50 in order to reduce the contact resistance between the two. The tablets were 10 mm in diameter and 1 mm in thickness. Such mixing and pressing steps were performed in a dry atmosphere. Further, a current collecting layer 3 made of aluminum and having a thickness of 100 μm was formed on one surface of the positive electrode and the negative electrode by plasma spraying.
And 4 were formed.

Using the tablet-shaped positive electrode 1, negative electrode 2, and electrolyte 5 thus produced, a coin-type electric double-layer capacitor having the same configuration as in Example 2 was produced.

After charging this capacitor at 2.8 V, 10
Constant current discharge at μA, capacity 0.24F, impedance 1
You got 6 ohms. 2.8 V at 70 ° C
Was applied, the rate of capacity decrease after 1000 hours with respect to the initial capacity was 9%.

Further, no leakage of the electrolytic solution was observed in the sample subjected to the experiment. The present embodiment can also be carried out using a possible combination system of an organic solvent such as ethylene carbonate, gamma-butyl lactone, dimethylformamide or dimethyl sulfoxide and an electrolyte salt such as tetraethylammonium perchlorate or tetraethylammonium borofluoride. Capacitors exhibiting substantially the same characteristics as those described above were produced.

Further, even when pitch-based or polyacrylonitrile (PAN) -based activated carbon particles were used instead of the phenol-based activated carbon particles, the characteristics were almost the same as those of the capacitor of this embodiment.

Example 4 Production of Composite Gel as Electrolyte
The starting composition is a molar ratio of Si (OEt)_Four, Ethanor
Water, sulfuric acid (dopant) at 1: 5: 10: 0.1
Stir at room temperature for 30 minutes and gel at a temperature of 60 ° C.
Was. The electrical conductivity of this gel is 4 × 10 ^-1Scm^-1
Met. The gel produced in this way is crushed and
Fine particles having a diameter of 30 μm were obtained. 3to using these fine particles
ncm^TwoPressed with pressure of 10mm in diameter, thickness
A 0.3 mm tablet was prepared and used as electrolyte 5.

Separately from the above composite gel, 50 wt% of phenolic activated carbon particles (specific surface area: 2000 m ² g ⁻¹ , average particle diameter 20 μm) were added to the above sol mixture.
After stirring for 0 minutes, it gelled at a temperature of 60 ° C. The electrical conductivity of this gel was 2 × 10 ⁻¹ Scm ⁻¹ at room temperature.
The composite gel prepared in this way is pulverized and the average particle size is 30 μm.
After the m of fine particles, and pressed at a pressure of 3 ton · cm ^2, to prepare a diameter 10 mm, thickness 1mm tablet-shaped positive electrode 1 and negative electrode 2. Further, one side of the positive electrode and the negative electrode is made of stainless steel by plasma spraying to have a thickness of 1 mm.
Current collecting layers 3 and 4 having a thickness of 00 μm were formed.

Using the tablet-shaped positive electrode 1, negative electrode 2 and electrolyte 5 thus produced, a coin-type electric double layer capacitor having the same configuration as in Example 1 was produced.

After charging this capacitor at 1.0 V, 10
Constant current discharge at μA, capacity 0.48F, impedance 6
Got an ohm. When 1.0 V was constantly applied in an atmosphere of 70 ° C., the capacity reduction ratio after 1000 hours with respect to the initial capacity was 9%. In addition, no leakage of the electrolyte solution was observed in the samples subjected to the experiment.

Other hydrochloric acid, heteropolyacid, perchloric acid,
Even when an acid or alkali electrolyte of potassium hydroxide was used, a capacitor having substantially the same characteristics as those of this example could be manufactured. When a conductive resin made of graphite / acrylic resin is used for the current collecting layer, the impedance becomes 11
Although it became larger in ohms, the reliability was almost the same as that of this embodiment.

Further, even when pitch-based or polyacrylonitrile (PAN) -based activated carbon particles were used instead of the phenol-based activated carbon particles, the characteristics were almost the same as those of the capacitor of this embodiment.

Example 5 As a starting composition of a composite gel as an electrolyte, a molar ratio of Si (OEt) ₄ , ethanol, water, propylene carbonate and tetraethylammonium perchlorate (dopant) was 1: 5: 1: 1. : 0.
The mixture was stirred at room temperature for 30 minutes using No. 1 and gelled at a temperature of 60 ° C. The electrical conductivity of this gel is 4 × 10 ⁻¹ Scm at room temperature.
It was ^-1 . The gel thus produced was pulverized into fine particles having an average particle size of 30 μm. 3t using these fine particles
It was press-molded at a pressure of on · cm ² to produce a tablet having a diameter of 10 mm and a thickness of 0.3 mm, which was used as an electrolyte 5.

Separately from the above composite gel, 50% by weight of phenolic activated carbon particles (specific surface area: 2000 m ² g ⁻¹ , average particle diameter 20 μm) were added to the above sol mixture.
After stirring for 0 minutes, it gelled at a temperature of 60 ° C. Further, the gel was heated at 110 ° C. to evaporate water. The electric conductivity of this gel was 9 × 10 ⁻⁴ Scm ⁻¹ at room temperature.
The gel prepared in this way is pulverized to an average particle size of 30 μm.
After the fine particles, and pressed at a pressure of 3 ton · cm ^2, to produce 10 mm, the positive electrode 1 and negative electrode 2 tablets shaped thickness 1mm diameter. Further, one side of the positive electrode and the negative electrode is made of stainless steel by plasma spraying to have a thickness of 10 mm.
Current collecting layers 3 and 4 having a thickness of 0 μm were formed.

Using the tablet-shaped positive electrode 1, negative electrode 2, and electrolyte 5 thus produced, a coin-type electric double layer capacitor having the same configuration as in Example 1 was produced. A series of steps for producing the capacitor was performed in a dry atmosphere.

After charging this capacitor at 2.8 V, 10
Constant current discharge at μA, capacity 0.22F, impedance 1
You got 9 ohms. 2.8 V at 70 ° C
Was applied, the capacity reduction rate after 1000 hours with respect to the initial capacity was 10%. In addition, no leakage of the electrolyte solution was observed in the samples subjected to the experiment. The present embodiment can also be carried out using a possible combination system of an organic solvent such as ethylene carbonate, gamma-butyl lactone, dimethylformamide or dimethyl sulfoxide and an electrolyte salt such as tetraethylammonium perchlorate or tetraethylammonium borofluoride. Capacitors exhibiting substantially the same characteristics as those described above were produced.

When a conductive resin made of graphite / acrylic resin is used for the current collecting layer, the impedance becomes 28%.
Although it became larger in ohms, the reliability was almost the same as that of this embodiment. Furthermore, even when pitch-based or polyacrylonitrile (PAN) -based activated carbon particles were used instead of the phenol-based activated carbon particles, characteristics substantially equivalent to those of the capacitor of this example were exhibited.

Example 6 The starting composition of the composite gel as the electrolyte was as follows: Si (OEt) ₄ , ethanol,
Water and sulfuric acid (dopant) were stirred at room temperature for 30 minutes using 1: 5: 10: 0.1 and gelled at a temperature of 60 ° C. The electric conductivity of this gel was 4 × 10 ⁻¹ Scm ⁻¹ at room temperature. The composite gel thus produced was pulverized into fine particles having an average particle size of 30 μm. 3ton using these fine particles
-Press-molding was performed at a pressure of cm ² to produce a tablet having a diameter of 10 mm and a thickness of about 150 μm, which was used as an electrolyte 5.

Separately from the above composite gel, 50 wt% of phenolic activated carbon particles (specific surface area: 2000 m ² g ^-1 , average particle diameter 20 μm) and 2 w
After adding t% fluororesin as a binder and stirring, 6%
It gelled at a temperature of 0 ° C. The composite gel thus produced was pulverized into fine particles having an average particle size of 30 μm,
Positive electrode 1 of a polarizable electrode by temporary press molding at a pressure of gcm ^-2
And negative electrode 2 were produced.

The temporarily pressed positive electrode 1 and the current collector 3 made of stainless steel mesh, or the negative electrode 2 and the current collector 4 were overlaid, and the whole was fully pressed at a pressure of 3 ton · cm ⁻² . The prepared mixture has a thickness of about 500 μm and a diameter of 10 mm.
Tablet.

Using the tablet-shaped positive electrode 1, negative electrode 2, and electrolyte 5 thus produced, a coin-type electric double layer capacitor having the same configuration as in Example 1 was produced.

After charging this capacitor at 1.0 V, 10
Discharge was performed at a constant current of μA to obtain a capacity of 0.2 F and an impedance of 3 ohms. When 1.0 V was constantly applied in an atmosphere of 70 ° C., the capacity reduction ratio after 1000 hours with respect to the initial capacity was 9%. In addition, no leakage of the electrolyte solution was observed in the samples subjected to the experiment. Using other hydrochloric acid, heteropolyacid, perchloric acid, potassium hydroxide or alkaline electrolyte, a capacitor having almost the same characteristics as those of this example could be produced. Furthermore, pitch-based polyacrylonitrile (P
Even when the AN) -based activated carbon particles were used, the characteristics were almost the same as those of the capacitor of this example.

Example 7 The starting composition of the composite gel as an electrolyte was as follows: Si (OEt) ₄ , ethanol,
Water, propylene carbonate, and tetraethylammonium perchlorate (dopant) were stirred at room temperature for 30 minutes using 1: 5: 1: 1: 0.1 and gelled at a temperature of 60 ° C. The composite gel thus produced was pulverized into fine particles having an average particle size of 30 μm. 3ton using these fine particles
-Press-molding was performed at a pressure of cm ² to produce a tablet having a diameter of 10 mm and a thickness of about 150 μm, which was used as an electrolyte 5.

Separately from the composite gel, 10 wt% of graphite fine particles (average particle size 0.5 μm) based on the sol mixture
Was added and the mixture was further stirred for 30 minutes, and then gelled at a temperature of 60 ° C. Further, the gel was heated at 110 ° C. to evaporate water. The electrical conductivity of this gel is 9 × 10 ^-4 S at room temperature.
cm ^-1 . The gel thus produced was pulverized into fine particles having an average particle size of 30 μm. 5 more for the mixture
0 wt% phenolic activated carbon particles (specific surface area: 200
0 m ² g ^-1 , average particle size 20 μm) and 2 wt.
% Of fluororesin and after stirring, 100kgcm
The positive electrode 1 and the negative electrode 2 as polarizable electrodes were prepared by temporary press molding at a pressure of ^-2 .

The positive electrode 1 and the current collector 3 made of stainless steel mesh or the negative electrode 2 and the current collector 4 which were temporarily press-formed were superimposed on each other at a pressure of 3 ton · cm ^-2 , and the whole was pressed to a thickness of about 500 μm and a diameter of 10 mm. Tablet was produced.

Using the tablet-shaped positive electrode 1, negative electrode 2, and electrolyte 5 thus manufactured, a coin-type electric double layer capacitor having the same configuration as in Example 1 was manufactured.

After charging this capacitor at 2.8 V, 10
Discharge was performed at a constant current of μA to obtain a capacity of 0.1 F and an impedance of 9 ohms. When 2.8 V was constantly applied in an atmosphere at 70 ° C., the capacity reduction rate after 1000 hours with respect to the initial capacity was 12%. In addition, no leakage of the electrolyte solution was observed in the samples subjected to the experiment. The present embodiment can also be carried out using a possible combination system of an organic solvent such as ethylene carbonate, gamma-butyl lactone, dimethylformamide or dimethyl sulfoxide and an electrolyte salt such as tetraethylammonium perchlorate or tetraethylammonium borofluoride. Capacitors exhibiting substantially the same characteristics as those described above were produced. When a conductive resin made of graphite / acrylic resin was used for the current collecting layer, the impedance increased to 14 ohms, but the reliability was almost the same as that of the present embodiment.

Further, even when pitch-based or polyacrylonitrile (PAN) -based activated carbon particles were used instead of the phenol-based activated carbon particles, characteristics equivalent to those of the capacitor of this embodiment were exhibited.

Example 8 The starting composition of the composite gel as the electrolyte was as follows: Si (OEt) ₄ , ethanol,
Water, propylene carbonate, and tetraethylammonium perchlorate (dopant) were stirred at room temperature for 30 minutes using 1: 5: 1: 1: 0.1 and gelled at a temperature of 60 ° C. The gel prepared in this way is pulverized to an average particle size of 30.
It was a fine particle of μm. 3ton · c using these fine particles
Press molding with a pressure of m ² , diameter 10 mm, thickness about 15
A tablet having a thickness of 0 μm was prepared and used as electrolyte 5.

Separately from the above-mentioned composite gel, 49% by weight of the above-mentioned composite gel and phenol-based activated carbon particles (specific surface area: 2000 m ² g ⁻¹ , average particle diameter 20 μm) as a material for the polarizable electrode
49 wt% and 2 wt% of a fluororesin as a binder were mixed by stirring, and 5 wt% of methanol was added to the above mixture, followed by stirring to form a slurry. This slurry is applied to a 0.5 mm thick aluminum mesh serving as a current collector and dried at 110 ° C. to hold the current collector. The positive electrode 1 and the negative electrode 2 each having a thickness of about 500 μm and a diameter of 10 mm are discarded. Produced.

The positive electrode 1 and the negative electrode 2 thus prepared,
Using the electrolyte 5, a coin-type electric double layer capacitor having the same configuration as that of FIG. This capacitor is 2.8V
After discharging, constant current discharge was performed at 10 μA to obtain a capacity of 0.07F and an impedance of 11 ohms. When 2.8 V was constantly applied in an atmosphere of 70 ° C., 10
The capacity reduction rate after 00 hours was 12%. In addition, no leakage of the electrolyte solution was observed in the samples subjected to the experiment.

Even when an aluminum foil or an expanded metal having a diagonal cut was used for the current collector, almost the same reliability as that of this embodiment was obtained. (Example 9) As a starting composition of a composite gel as a polarizable electrode, a molar ratio of Si (OEt) ₄ , ethanol, water, propylene carbonate, and tetraethylammonium perchlorate (dopant) was 1: 5: 1: 1: The mixture was stirred at room temperature for 30 minutes using 0.1, and further added to the mixed sol for 5 minutes.
0 wt% phenolic activated carbon particles (specific surface area: 200
0 m ² g ⁻¹ , average particle size 20 μm) and further stirred for 30 minutes. Then, 0.5 mm-thick mesh-like aluminum serving as a current collector was immersed in the gel, and the gelation was advanced at 60 ° C. The composite gel and the activated carbon were held on the current collector by further drying at a temperature of about 500 μm and a diameter of about 500 μm.
The positive electrode 1 and the negative electrode 2 were 0 mm.

Separately from the above gel, a sol to which 50% by weight of phenolic activated carbon particles had not been added was prepared.
By repeating application and drying at 60 ° C. on one side of the negative electrode 2, an electrolyte layer 5 having a thickness of 100 μm was formed and dried at 110 ° C.

The thus prepared positive electrode 1 and negative electrode 2
Using the electrolyte 5, a coin-type electric double layer capacitor having the same configuration as that of FIG. This capacitor is 2.8V
, And discharged at a constant current of 10 μA to obtain a capacity of 0.09F and an impedance of 8 ohms. When 2.8 V was constantly applied in an atmosphere of 70 ° C., 100
The capacity reduction rate after 0 hour was 12%. In addition, no leakage of the electrolyte solution was observed in the samples subjected to the experiment.

Other ethylene carbonate, gamma-
Even when using a system of a possible combination of an organic solvent such as butyl lactone, dimethylformamide or dimethyl sulfoxide and an electrolyte salt such as tetraethylammonium perchlorate or tetraethylammonium borofluoride, the characteristics are almost the same as those of this example. A capacitor could be manufactured.

Further, even when pitch-based or polyacrylonitrile (PAN) -based activated carbon particles were used in place of the phenol-based activated carbon particles, almost the same characteristics as those of the capacitor of this embodiment were exhibited.

Example 10 As a starting composition of a composite gel as a polarizable electrode, a molar ratio of Si (OEt) ₄ , ethanol, water, propylene carbonate and tetraethylammonium perchlorate (dopant) was 1: 5: 1. : 1:
The mixture was stirred at room temperature for 30 minutes using 0.1, and 50% by weight of phenol-based activated carbon particles (specific surface area: 2000 m ² g ^-1 , average particle diameter: 20 μm) were added to the mixed sol.
After adding fine graphite particles (average particle size: 0.5 μm) by weight and stirring for further 30 minutes, a 0.5 mm thick aluminum mesh serving as a current collector was immersed in the gel, and gelation was allowed to proceed at 60 ° C. By further drying at 110 ° C.,
The composite gel, activated carbon and graphite fine particles are held on the current collector,
A positive electrode 1 and a negative electrode 2 having a thickness of about 500 μm and a diameter of 10 mm were obtained.

Separately from the above gel, a sol to which phenol-based activated carbon particles and graphite fine particles were not added was prepared, applied to one surface of the positive electrode 1 and the negative electrode 2 and dried at 60 ° C. repeatedly, whereby an electrolyte layer having a thickness of 100 μm was obtained. 5 to form 110
Dry at ℃.

The positive electrode 1 and the negative electrode 2 thus prepared,
Using the electrolyte 5, a coin-type electric double layer capacitor having the same configuration as that of FIG. This capacitor is 2.8V
, And discharged at a constant current of 10 μA to obtain a capacity of 0.12F and an impedance of 7 ohms. When 2.8 V was constantly applied in an atmosphere of 70 ° C., 100
The capacity reduction rate after 0 hour was 8%. In addition, no leakage of the electrolyte solution was observed in the samples subjected to the experiment.

Other ethylene carbonate, gamma-
Even when using a system of a possible combination of an organic solvent such as butyl lactone, dimethylformamide or dimethyl sulfoxide and an electrolyte salt such as tetraethylammonium perchlorate or tetraethylammonium borofluoride, the characteristics are almost the same as those of this example. A capacitor could be manufactured.

Further, even when pitch-based or polyacrylonitrile (PAN) -based activated carbon particles were used instead of the phenol-based activated carbon particles, the same characteristics as those of the capacitor of this embodiment were exhibited.

Example 11 As the starting composition of the composite gel, Si (OEt) ₄ , ethanol, water, propylene carbonate and tetraethylammonium perchlorate (dopant) were used in a molar ratio of 1: 5: 1: 1: 0. Stir for 30 minutes at room temperature using No. 1 and apply a thickness of 1
A phenolic activated carbon fiber cloth (specific surface area: 2000 m ² g ⁻¹ , unit weight: 120 g · cm ² ) having an aluminum current collector layer of 00 μm is immersed, gelation proceeds at 60 ° C., and further drying at 110 ° C. As a result, the composite gel is held on the activated carbon fiber cloth and has a thickness of about 800 μm and a diameter of 10 μm.
mm positive electrode and negative electrode. Then, by applying the above sol to one surface of the positive electrode and the negative electrode and repeating drying at 60 ° C.,
An electrolyte layer 5 having a thickness of 100 μm was formed and dried at 110 ° C.

The positive electrode 1 and the negative electrode 2 thus manufactured,
Using the electrolyte 5, a coin-type electric double layer capacitor having the same configuration as that of FIG. This capacitor is 2.8V
After discharging the battery at a constant current of 10 μA, a capacity of 0.24 F and an impedance of 20 ohms were obtained. When 2.8 V was constantly applied in an atmosphere of 70 ° C., 10
The capacity reduction rate after 00 hours was 8%. In addition, no leakage of the electrolyte solution was observed in the samples subjected to the experiment.

Other ethylene carbonate, gamma-
Even when using a system of a possible combination of an organic solvent such as butyl lactone, dimethylformamide or dimethyl sulfoxide and an electrolyte salt such as tetraethylammonium perchlorate or tetraethylammonium borofluoride, the characteristics are almost the same as those of this example. A capacitor could be manufactured.

Further, even when a pitch-based or polyacrylonitrile (PAN) -based activated carbon fiber cloth was used in place of the phenol-based activated carbon fiber cloth, the same characteristics as those of the capacitor of the present example were exhibited.

Example 12 As the starting composition of the composite gel, Si (OEt) ₄ , ethanol, water, propylene carbonate and tetraethylammonium perchlorate (dopant) were used in a molar ratio of 1: 5: 1: 1: 0. And stirred at room temperature for 30 minutes.
3% by weight of graphite fine particles (average particle size: 0.5 μm)
After stirring for 0 minutes, a thickness of 1
A phenol-based activated carbon fiber cloth (specific surface area: 2000 m ² g ⁻¹ , unit weight: 120 g · cm ² ) having an aluminum current collector layer of 00 μm is immersed, gelling proceeds at 60 ° C., and further dried at 110 ° C. The thickness of the composite gel held on the activated carbon fiber cloth was about 800 μm and the diameter was 10 m.
m positive electrode and negative electrode.

Separately from the above sol, a sol containing no graphite particles was applied to one surface of each of the positive electrode 1 and the negative electrode 2 and dried at 60 ° C. repeatedly to form an electrolyte layer 5 having a thickness of 100 μm.
Was formed and dried at 110 ° C.

The thus prepared positive electrode 1 and negative electrode 2
Using the electrolyte 5, a coin-type electric double layer capacitor having the same configuration as that of FIG. This capacitor is 2.8V
After discharging the battery at a constant current of 10 μA, a capacity of 0.26 F and an impedance of 16 ohms were obtained. When 2.8 V was constantly applied in an atmosphere of 70 ° C., 10
The capacity reduction rate after 00 hours was 4%. In addition, no leakage of the electrolyte solution was observed in the samples subjected to the experiment.

Other ethylene carbonate, gamma-
Even when using a system of a possible combination of an organic solvent such as butyl lactone, dimethylformamide or dimethyl sulfoxide and an electrolyte salt such as tetraethylammonium perchlorate or tetraethylammonium borofluoride, the characteristics are almost the same as those of this example. A capacitor could be manufactured.

Further, even when a pitch-based or polyacrylonitrile (PAN) -based activated carbon fiber cloth was used in place of the phenol-based activated carbon fiber cloth, the same characteristics as those of the capacitor of this example were exhibited.

[0108]

As described above, in the electric double layer capacitor of the present invention, the polarizable electrode on the positive electrode side and the polarizable electrode on the negative electrode side face each other via the electrolyte using the composite gel composed of the dopant and the matrix gel. Each polarizable electrode is provided with a current collector made of a metal or a conductive resin, and is formed at the interface between electrolyte ions and activated carbon of the composite gel by using activated carbon for the polarizable electrodes on the positive electrode side and the negative electrode side. Since the electric double layer capacity is used, there is no part that is degraded by the electrochemical reaction, the decomposition voltage is relatively high, and
It is a highly reliable electric double layer capacitor that can reduce internal resistance and has no liquid leakage because the electrolyte is in a gel state.

When the matrix gel is at least one selected from silica gel, alumina gel, and titania gel, the chemical stability of the electric double layer capacitor is improved.

Next, in the first production method of the present invention, a composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant and a metal alkoxide, and activated carbon is added to the composite gel produced from the mixed sol. Mixing to form a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side, forming a current collector made of a metal or a conductive resin on each of the polarizable electrodes, and separating the collector on the positive electrode side through the electrolyte By providing the polar electrode and the polarizable electrode on the negative electrode side facing each other, a polarizable electrode having a uniform composition can be obtained, and an electric double layer capacitor without electrolyte leakage can be manufactured.

Further, in the second production method of the present invention, a composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant and a metal alkoxide, and a mixed sol comprising a dopant, a metal alkoxide and an activated carbon is hydrolyzed. By forming a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side by decomposition, a current collector made of a metal or a conductive resin is formed on each of the polarizable electrodes, and the positive electrode side is interposed through the electrolyte. The polarizable electrode having a uniform composition can be obtained by providing the polarizable electrode and the polarizable electrode on the negative electrode side to face each other, and an electric double layer capacitor free of electrolyte leakage can be manufactured.

Further, in the third production method of the present invention, a composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant and a metal alkoxide. A positive electrode-side polarizable electrode and a negative electrode-side polarizable electrode are mixed with each other, and each of the polarizable electrodes is press-formed with a current collector made of a metal or a conductive resin, and the positive electrode is interposed through the electrolyte. By providing the polarizable electrode on the negative electrode side and the polarizable electrode on the negative electrode side opposite to each other, a polarizable electrode having a uniform composition can be obtained, and an electric double layer capacitor free of electrolyte leakage can be easily manufactured.

In the first, second or third production method, at least one organic solvent selected from ethylene carbonate, propylene carbonate, gamma-butyl lactone, dimethylformamide and dimethyl sulfoxide is further added to the mixed sol. Is preferable because these organic solvents have a high boiling point of 200 ° C. or higher and are chemically stable.

Further, in the fourth production method of the present invention, a composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant, a metal alkoxide and an organic solvent, After mixing the activated carbon and the binder, the mixture is applied to a metal current collector to form a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side, and the polarizable electrode on the positive electrode side and the negative electrode side are separated via the electrolyte. By providing the polar electrodes facing each other, the composite gel, the activated carbon and the mixture of the binder can be held on the metal current collector, so that a positive electrode and a negative electrode having a uniform composition are obtained, and the internal resistance of the current collector is excellent. A small, highly reliable electric double layer capacitor can be manufactured.

Further, in the fifth production method of the present invention, the polarizable electrode on the positive electrode side is obtained by immersing a metal current collector in a mixed sol comprising a dopant, a metal alkoxide, an organic solvent and activated carbon and hydrolyzing the sol. A polarizable electrode on the negative electrode side is formed, and a mixed sol comprising a dopant, a metal alkoxide, and an organic solvent is applied to each of the polarizable electrodes and hydrolyzed to produce a composite gel as an electrolyte, via the electrolyte. By providing the polarizable electrode on the positive electrode side and the polarizable electrode on the negative electrode side opposite to each other, the composite sol can be held on the metal current collector, so that a positive electrode and a negative electrode having a uniform composition can be obtained, A highly reliable electric double layer capacitor with excellent internal resistance and low internal resistance can be manufactured.

Further, according to a sixth production method of the present invention, after forming a metal current collector layer on an activated carbon fiber cloth, the activated carbon fiber cloth is immersed in a mixed sol comprising a dopant, a metal alkoxide and an organic solvent to carry out hydrolysis. To form a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side, to prepare a composite gel as an electrolyte by applying the mixed sol to each of the polarizable electrodes and hydrolyzing it, By providing the polarizable electrode on the positive electrode side and the polarizable electrode on the negative electrode side through the composite gel, the composite gel can be held on the metal current collector, so that a positive electrode and a negative electrode having a uniform composition can be obtained. It is possible to manufacture a highly reliable electric double layer capacitor having excellent internal performance and small internal resistance.

In the first to sixth production methods, when graphite fine particles are further mixed with the mixed sol used for the polarizable electrode, the electric resistance of the polarizable electrode can be reduced by adding the graphite fine particles. A small, highly reliable electric double layer capacitor can be manufactured.

Further, in the electric double layer capacitor of the present invention or the first to sixth methods for producing the same, the dopant is an acid or alkali of hydrochloric acid, sulfuric acid, heteropolyacid, perchloric acid, potassium hydroxide, tetraethylammonium perchlorate. And at least one selected from tetraethylammonium borofluoride, an acid or an alkali solution can increase the electric conductivity and reduce the internal resistance of the capacitor. In addition, tetraethylammonium perchlorate and tetraethylammonium borofluoride can be used. An organic electrolyte using an electrolyte salt as described above has a high decomposition voltage and can increase the withstand voltage of the capacitor.

Further, in the electric double layer capacitor of the present invention or the first to sixth methods for producing the same, the activated carbon is phenol-based, pitch-based, and polyacrylonitrile (PA).
When at least one selected from powdered or fibrous activated carbons of the N) type, these activated carbons have a specific surface area of at least 2,000 m ² g ⁻¹ , which is at least twice that of coconut shell charcoal,
Further, the pore diameter can be controlled in the range of 2 to 4 nm, and the capacity of the double layer can be increased.

Further, in the electric double layer capacitor of the present invention or the first to sixth production methods thereof, when the metal used for the current collector is at least one selected from aluminum, titanium and stainless steel, the polarizable electrode In particular, the electrochemical stability of the positive electrode is improved.

In the fourth to sixth production methods of the present invention, when the organic solvent is at least one selected from ethylene carbonate, propylene carbonate, gamma-butyl lactone, dimethylformamide and dimethyl sulfoxide, Organic solvents have a boiling point of 200
It is convenient because it is chemically stable as high as ℃ or more.

The composite gel of the present invention can be applied not only as an electrolyte for electric double layer capacitors but also as an electrolyte for batteries and electrochromic devices.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an electric double layer capacitor according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 Current collector 4 Current collector 5 Electrolyte 6 Upper member (sealing plate) 7 Lower member (case) 8 Packing

Continuation of the front page (72) Inventor Tsutomu Minami 1-1, Gakuen-cho, Sakai City, Osaka Prefecture Osaka University Prefectural University (56) References JP-A-6-20875 (JP, A) JP-A 5-304048 (JP, A) JP-A-62-115706 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 9/038 H01G 9/016 H01G 9/025 H01G 9/058

Claims (14)

(57) [Claims] 1. A polarizable electrode on a positive electrode side and a polarizable electrode on a negative electrode side are opposed to each other via an electrolyte using a composite gel comprising a dopant and a matrix gel, and each polarizable electrode is made of metal or conductive resin. An electric double layer capacitor comprising a current collector and using activated carbon for the polarizable electrodes on the positive and negative electrode sides. 2. The electric double layer capacitor according to claim 1, wherein the matrix gel is at least one selected from silica gel, alumina gel, and titania gel. 3. A composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant and a metal alkoxide. Activated carbon is mixed into the composite gel produced from the mixed sol, and a polarizable electrode on the positive electrode side and a negative electrode on the negative electrode side. Are formed, a current collector made of a metal or a conductive resin is formed on each of the polarizable electrodes, and the polarizable electrode on the positive electrode side and the polarizable electrode on the negative electrode side are relatively opposed via the electrolyte. A method for manufacturing an electric double layer capacitor provided to face. 4. A composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant and a metal alkoxide, and a polarizable electrode on the positive electrode side is produced by hydrolyzing a mixed sol comprising a dopant, a metal alkoxide and activated carbon. And a polarizable electrode on the negative electrode side, a current collector made of a metal or a conductive resin is formed on each of the polarizable electrodes, and the polarizable electrode on the positive electrode side and the polarizable property on the negative electrode side via the electrolyte. A method for manufacturing an electric double layer capacitor provided with electrodes facing each other. 5. A composite gel as an electrolyte is produced by hydrolyzing a mixed sol comprising a dopant and a metal alkoxide, and activated carbon and a binder are mixed with the composite gel produced from the mixed sol, and a polarizable electrode on the positive electrode side is produced. And a polarizable electrode on the negative electrode side, each of the polarizable electrodes is press-formed together with a current collector made of a metal or a conductive resin, and the polarizable electrode on the positive electrode side and the negative electrode side are separated via the electrolyte. A method for manufacturing an electric double layer capacitor provided with polar electrodes facing each other. 6. The mixed sol according to claim 3, further comprising at least one organic solvent selected from ethylene carbonate, propylene carbonate, gamma-butyl lactone, dimethylformamide, and dimethyl sulfoxide. Method for manufacturing electric double layer capacitor. 7. A composite gel as an electrolyte is prepared by hydrolyzing a mixed sol comprising a dopant, a metal alkoxide and an organic solvent, and after mixing the composite gel prepared from the mixed sol, activated carbon, and a binder, An electric electrode which is applied to a current collector to form a polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side, and is provided with the polarizable electrode on the positive electrode side and the polarizable electrode on the negative electrode side facing each other via the electrolyte. A method for manufacturing a multilayer capacitor. 8. A polarizable electrode on the positive electrode side and a polarizable electrode on the negative electrode side are formed by immersing a metal current collector in a mixed sol comprising a dopant, a metal alkoxide, an organic solvent and activated carbon and hydrolyzing the sol. , A mixed sol comprising a dopant, a metal alkoxide and an organic solvent is applied to each of the polarizable electrodes and hydrolyzed to produce a composite gel as an electrolyte, and the polarizable electrode and the negative electrode on the positive electrode side via the electrolyte. A method for manufacturing an electric double layer capacitor in which polarizable electrodes on the side are provided to face each other. 9. After forming a metal current collector layer on an activated carbon fiber cloth, the activated carbon fiber cloth is immersed in a mixed sol comprising a dopant, a metal alkoxide and an organic solvent and hydrolyzed to form a polarizable electrode on the positive electrode side. Form a polarizable electrode on the negative electrode side, prepare a composite gel as an electrolyte by applying and hydrolyzing the mixed sol to each of the polarizable electrodes, and the polarizable electrode on the positive electrode side via the electrolyte A method for manufacturing an electric double layer capacitor in which polarizable electrodes on the negative electrode side are provided to face each other. 10. The method for producing an electric double layer capacitor according to claim 3, wherein graphite fine particles are further mixed with the mixed sol used for the polarizable electrode. 11. The method according to claim 1, wherein the dopant is at least one selected from hydrochloric acid, sulfuric acid, heteropolyacid, perchloric acid, acid or alkali of potassium hydroxide, tetraethylammonium perchlorate, and tetraethylammonium borofluoride. The method for manufacturing an electric double layer capacitor according to claim 3, or an electric double layer capacitor according to claim 3, 4, 5, 7, 8, or 9. 12. The electric double layer capacitor according to claim 1, wherein the activated carbon is at least one selected from powdered or fibrous activated carbon of phenol type, pitch type, and polyacrylonitrile (PAN) type. ,
10. The method for producing an electric double layer capacitor according to 4, 5, 7, 8 or 9. 13. The metal used for the current collector is aluminum,
The method for producing an electric double layer capacitor according to claim 1, wherein the electric double layer capacitor is at least one selected from titanium and stainless steel. 14. The electric double layer capacitor according to claim 7, wherein the organic solvent is at least one selected from ethylene carbonate, propylene carbonate, gamma-butyl lactone, dimethylformamide, and dimethyl sulfoxide. Manufacturing method.