JP4294067B2 - Electric double layer capacitor using polyaniline / carbon composite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain, in an easier way, polyaniline or its derivative/carbon composite capable of providing an electric double-layer capacitor excellent in high electrostatic capacity and cycle characteristics in an electric double-layer capacitor using a conductive high molecular compound as a polarizable electrode. <P>SOLUTION: In a polyaniline/carbon composite composed of polyaniline or its derivative combined with a carbonaceous material, the polyaniline or its derivative is one in which a conductive polyaniline or its derivative dispersed in a nonpolar organic solvent is dedoped. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

The present invention relates to an electric double layer capacitor using a polyaniline / carbon composite, and more specifically, an electric double layer using a polyaniline / carbon composite capable of providing an electric double layer capacitor having high capacitance and excellent cycle characteristics. The present invention relates to a capacitor electrode material and an electric double layer capacitor .

  Conventionally, activated carbon or fibrous activated carbon is usually used as the polarizable electrode of the electric double layer capacitor. However, this has a problem that the discharge capacity is small, so that it is not possible to maintain the discharge for a long time in practical use. It was.

  In order to solve such a problem, Patent Documents 1 and 2 disclose a conductive polymer / carbon composite prepared by electrolytic polymerization of a conductive polymer in a suspension of activated carbon (or carbon). Proposed to be a polarizable electrode of a multilayer capacitor, polyaniline / carbon composite is used in practice as a polarizable electrode. According to this, there is an advantage that the specific capacitance is larger and the internal resistance is smaller than when a conventional polarizable electrode is used. However, the electrolytic polymerization method has a problem that polymerization in a large area is difficult and not industrial because the electrode area to be obtained is limited. Patent Document 3 discloses a polyaniline / carbon composite composed of a porous carbon-based material and polyaniline by chemically polymerizing aniline in an aqueous solution in the presence of a porous carbon-based material (for example, activated carbon). Although it has been proposed to be used as a polarizable electrode, there is a problem that the operation becomes complicated because the resulting polyaniline / carbon composite must be washed with water. Further, in the composite of Patent Document 3, after impregnating a porous carbon-based material with aniline, aniline is polymerized to form polyaniline on the porous carbon-based material. There is a problem that it is difficult to significantly reduce the capacitance.

  According to Patent Document 4, polyaniline sulfonic acids, an electrode active material (for example, activated carbon), and a carbon-based conductive material are mixed in water, and then water as a mixed solvent is distilled off in vacuo to obtain a polyaniline / carbon composite. And using this as a capacitor electrode has been proposed. However, a capacitor using an aqueous electrolyte has a problem that water-soluble polyaniline sulfonic acids are likely to be eluted from the electrode, resulting in poor long-term stability as a capacitor electrode. In addition, in a capacitor using an organic solvent-based electrolyte, the water used in the production of the electrode cannot be completely removed from the electrode due to the high affinity of polyaniline sulfonic acids for water, resulting in a decrease in driving voltage and a long-term cycle. There is a problem that the characteristics are inferior. There is also a problem that the driving voltage is lowered due to the side chain sulfonic acid groups of the polyaniline sulfonic acids. Further, since dedoped polyaniline (emeraldine base type) can be dispersed and dissolved in N-methyl-2-pyrrolidone (NMP), polyaniline / NMP solution, electrode active material (for example, activated carbon), and carbon-based conductivity. After mixing the substances, it has been proposed to obtain a polyaniline / carbon composite by heating and distilling off NMP, which is a mixed solvent, as a capacitor electrode. However, the polyaniline / NMP solution includes a state in which polyaniline particles are dissolved in NMP and a state in which polyaniline aggregates are dispersed in NMP. The polyaniline / carbon composite also contains polyaniline aggregates. End up. Since polyaniline aggregates cannot perform high-speed and quantitative electrochemical reactions, in the electrode using the above composite, the combined polyaniline cannot sufficiently contribute to the improvement of the discharge capacity, and the polyaniline is combined. It was difficult to improve the discharge capacity corresponding to the amount.

Japanese Patent Laid-Open No. 7-201676 JP 2002-25868 A JP 2002-25865 A JP 2003-17370 A

Therefore, the present invention eliminates the problems of the prior art described above, and more easily, in an electric double layer capacitor using a conductive polymer as a polarizable electrode, has a high capacitance and excellent cycle characteristics. The object is to obtain a polyaniline or its derivative / carbon composite electrode material which gives a double layer capacitor.

According to the present invention, a polyaniline or a derivative thereof, activated carbon, ketjen black, a polyaniline / carbon composite body formed by compounding a carbon-based material selected from acetylene black, and furnace black, the polyaniline or a derivative thereof Electrode material for an electric double layer capacitor using a polyaniline / carbon composite, which is obtained by subjecting a conductive polyaniline or a derivative thereof dispersed in a nonpolar organic solvent to base treatment and undoping, and an active material thereof An electric double layer capacitor having a polarizable electrode used as is provided.

  According to the present invention, a conductive polyaniline or a derivative thereof stably dispersed in a nonpolar organic solvent is subjected to base treatment and used in a dedoped state, thereby providing high capacitance and excellent charge / discharge characteristics. An electrode material for an electric double layer capacitor exhibiting excellent cycle characteristics can be obtained by a simple method.

  As a result of researches to solve the above problems, the present inventors have produced a conductive polyaniline dispersion liquid in which polyaniline is dispersed in a nonpolar organic solvent and is stable in this nonpolar organic solvent. The polyaniline / carbon composite is prepared by base treatment of the conductive polyaniline dispersed in the base material and combining with the carbon-based material in the dedope state, and bonding the polarizable electrode to the current collector. By configuring it, the above-mentioned purpose was successfully achieved.

  In the present invention, a conductive polyaniline dispersion in a doped state can be efficiently produced in a large amount by chemically polymerizing polyaniline or a derivative thereof in a nonpolar organic solvent. The polyaniline or derivative thereof used in the present invention is usually obtained by oxidative polymerization of aniline or derivative thereof or any mixture thereof. As the aniline derivative, an alkyl group, an alkenyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an alkylaryl group, an arylalkyl group, or an alkoxyalkyl group is used as a substituent at a position other than the 4-position of the aniline. The aniline derivative which has two can be illustrated. Preferred examples include aniline derivatives having at least one alkyl group having 1 to 5 carbon atoms, an alkoxy group, an alkoxyalkyl group, preferably an aryl group having 6 to 10 carbon atoms as a substituent.

  The dopant used in the present invention can be any sulfonic acid capable of dispersing polyaniline in a non-polar solvent, specifically an aliphatic or aromatic sulfone having one or more sulfonic acid groups. Acids and salts thereof, alkyl sulfonic acid, aryl sulfonic acid, alkyl aryl sulfonic acid, α-olefin sulfonic acid, sulfonic acid of higher aliphatic ester, (di) alkyl sulfosuccinic acid, sulfonic acid of higher aliphatic amide, And camphorsulfonic acid and salts thereof, preferably dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, octadecylbenzenesulfonic acid, dodecylsulfonic acid, tetradecylsulfonic acid, octadecylsulfonic acid, dodecylsulfosuccinic acid, didodecyl Sulfoco Click acid and salts thereof. The amount of these dopants to be used is not particularly limited, but is desirably 0.01 to 5 mol, more preferably 0.1 to 3 mol, per mol of aniline or a derivative thereof.

  The oxidizing agent for oxidative polymerization of aniline is not particularly limited as long as it can polymerize the above aniline or a derivative thereof. For example, persulfates such as ammonium persulfate, persulfuric acid, sodium persulfate, potassium persulfate and the like. Redox initiators such as hydrogen peroxide, ferric chloride, ferric sulfate, potassium dichromate, potassium permanganate, and hydrogen peroxide-ferrous salt are preferably used. These oxidizing agents may be used alone or in combination of two or more. The amount of the oxidizing agent used is not particularly limited as long as it is an amount capable of oxidative polymerization of the above aniline or derivative thereof, but is preferably 0.01 to 10 mol, more preferably 1 mol per mol of aniline or derivative thereof. Is 0.1 to 5 mol.

  Examples of the molecular weight modifier used in the present invention include an aniline derivative having a substituent at the 4-position, a thiol compound, a disulfide compound and / or an α-methylstyrene dimer. Examples of the aniline derivative having a substituent X at the 4-position include formula (I):

The compound shown by can be mention | raise | lifted. In the formula (I), X represents an alkyl group, an alkenyl group, an alkoxyl group, an alkylthio group, an aryl group, an aryloxy group, an alkylaryl group, an arylalkyl group, an alkoxyalkyl group, or a halogen group, and Y represents a hydrogen atom or an alkyl group. A group, an alkenyl group, an alkoxyl group, an alkylthio group, an aryl group, an aryloxy group, an alkylaryl group, an arylalkyl group, an alkoxyalkyl group, and a halogen group, n represents an integer of 0 to 4, and n represents 2 to 4 Y may be the same or different. Preferred substituents X are alkyl groups having 1 to 5 carbon atoms, alkoxy groups, alkoxyalkyl groups, and aryl groups having 6 to 10 carbon atoms, and preferred substituents Y are hydrogen atoms and alkyl groups having 1 to 5 carbon atoms. , An alkoxy group, an alkoxyalkyl group, and an aryl group having 6 to 10 carbon atoms.

Examples of the thiol compound and / or disulfide compound used in the present invention include butyl mercaptan, octyl mercaptan, dodecyl mercaptan, hexadecyl mercaptan, tetradecyl mercaptan, 2,2,4,6,6-pentamethylheptane-4-methylenethiol. Thiol compounds such as diethyl disulfide, alkyl disulfides such as dibutyl disulfide, aromatic disulfides such as diphenyl disulfide and dibenzyl disulfide, xanthogen disulfides such as dimethyl xanthogen disulfide and diethyl xanthogen disulfide, tetramethyl thiuram disulfide, tetraethyl thiuram disulfide And disulfide compounds such as thiuram disulfides. These are known compounds, many of which are generally commercially available. The amount of the molecular weight modifier used is not particularly limited, but is preferably 5.0 × 10 ^{−5 to} 5.0 × 10 ⁻¹ mol per mol of aniline or a derivative thereof, and 2.0 × 10 ^−4. It is more preferable to use ~ 2.0 × 10 ^-1 mol.

  The phase transfer catalyst used in the preferred embodiment of the present invention is not particularly limited as long as it is generally used as a phase transfer catalyst. Specifically, benzyltriethylammonium chloride, methyltrioctylammonium chloride, tetra- tetraalkylammonium halides such as n-butylammonium bromide, tetra-n-butylammonium iodide, tetra-n-butylammonium chloride; tetraalkylammonium hydroxides such as tetrabutylammonium hydroxide; methyltriphenylphosphonium bromide, etc. Tetraalkylphosphonium halides; crown ethers such as 12-crown-4,15-crown-5,18-crown-6, etc. Point tetraalkylammonium halides are preferred in the ease of handling such as removal of the catalyst after Chi reaction, especially industrially inexpensively available tetra -n- butylammonium bromide or tetra -n- butyl chloride are preferred. In the present invention, the amount of the phase transfer catalyst to be used is not particularly limited as necessary, but it is preferably 0.0001 mol times or more, more preferably 0.005 mol times or more, relative to the oxidizing agent. However, if an excessive amount of phase transfer catalyst is used, the isolation and purification steps after the completion of the reaction become difficult. Therefore, when used, the amount is preferably 5 moles or less, more preferably equimolar or less. Used in a range.

  With respect to the method for oxidative polymerization of aniline or a derivative thereof according to the present invention, conventional methods can be adopted except that the use of the reaction components is an essential requirement, and other general-purpose additives are also used in the present invention. As long as the purpose is not impaired, the conventional method can be adopted. The polymerization medium of the present invention uses two liquid media such as water and an organic solvent as a solvent. The organic solvent is not particularly limited as long as it dissolves aniline or a derivative thereof and is water-insoluble, and specific examples thereof include aromatic hydrocarbons such as benzene, toluene, xylene; hexane, heptane, octane, etc. Aliphatic hydrocarbons: halogenated hydrocarbons such as dichloroethane, chloroform, 1,2-dichloroethane, chlorobenzene, dichlorobenzene; diethyl ether, di-n-propyl ether, diisopropyl ether, di-n-butyl ether, tert- Ethers such as butyl methyl ether; esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, and n-butyl acetate are preferable. Of these, aromatic hydrocarbons, aliphatic hydrocarbons, and halogenated compounds are preferable. Hydrocarbons, particularly preferably torr It is down and xylene. You may use the said organic solvent in mixture of 2 or more types. The liquid medium may be used in any amount that can be stirred, and is usually used in an amount of 1 to 500 times, preferably 2 to 300 times the amount of aniline or a derivative thereof. Here, the amount of the organic solvent used is 0.05 to 30 times by weight, preferably 0.1 to 10 times by weight with respect to water.

Although there is no restriction | limiting in particular in reaction temperature, Preferably it is -10 degreeC-80 degreeC. Polyaniline oxidatively polymerized according to the present invention has a very high yield, usually 80% or more, and its electric conductivity is 10 ^-9 Scm ^-1 or more.

  According to the present invention, the polyaniline or the derivative thereof is present in the mixed solvent composed of the two kinds of liquid solvents, that is, water and an organic solvent (for example, toluene and xylene), and the presence of the molecular weight regulator and the phase transfer catalyst. Below, it is chemically polymerized with the above-mentioned dopant (for example, dodecylbenzenesulfonic acid, tetradecylbenzenesulfonic acid, octadecylbenzenesulfonic acid, dodecylsulfonic acid, tetradecylsulfonic acid, octadecylsulfonic acid, dodecylsulfosuccinic acid, didodecylsulfosuccinic acid). Can be obtained. The obtained polyaniline or a derivative thereof is stably dispersed in a nonpolar organic solvent in a doped state due to the steric effect of the dopant and the affinity of the dopant with the nonpolar solvent. Further, the obtained polyaniline or a derivative thereof has a particle size of 0.5 μm or less, a particle size distribution is monodispersed, and is stably dispersed in a nonpolar solvent. Therefore, the polyaniline or derivative thereof of the polyaniline / carbon composite of the present invention described later is compounded with the carbon-based material independently and in a highly dispersed state without aggregation of particles.

The carbon-based material used in the present invention is , for example , carbon black such as powdered, granular, fibrous or molded activated carbon, ketjen black, acetylene black, furnace black , and the specific surface area is 20 m ² / g or more ( A carbon-based material (measured by a nitrogen adsorption method) is desirable. These carbon materials may be used alone or as a mixture of various carbon materials. Carbon-based materials are known. For example, Kuraray Chemical Co., Ltd. Fine Activated Carbon RP, Fine Activated Carbon YP, Lion Corporation Ketjen Black EC300J, Ketjen Black EC600JD, Denka Black FX-35 manufactured by Denki Kagaku Kogyo Co., Ltd. , And commercially available as HS-100 .

  The polyaniline or derivative thereof of the polyaniline / carbon composite according to the present invention is obtained by subjecting the conductive polyaniline of the conductive polyaniline dispersion to base treatment and dedoping, and this dedope-treated polyaniline or derivative thereof. The amount used is not particularly limited, but it is preferably 1 to 300 parts by weight per 100 parts by weight of the carbon-based material. If this ratio is small, there is a possibility that a sufficient increase in capacity may not be seen, and conversely if it is large, not only an effect commensurate with the amount of polyaniline mixed can be obtained, but it is also difficult to make a composite with a carbon-based material. Absent.

Examples of the preparation of the polyaniline / carbon composite of the present invention include the following methods.
(1) A polyaniline / carbon composite is prepared by base treatment of a dispersion obtained by mixing a conductive polyaniline dispersion and a carbon-based material. The polyaniline / carbon composite can be isolated by filtering and washing the solid content in the dedope-treated dispersion.
(2) A conductive polyaniline / carbon composite is obtained by removing the solvent from the dispersion obtained by mixing the conductive polyaniline dispersion and the carbonaceous material. A polyaniline / carbon composite is prepared by treating the resulting composite with a base.
(3) A de-doped polyaniline dispersion is obtained by base treatment of a dispersion obtained by mixing a conductive polyaniline dispersion and an aprotic solvent. After mixing the carbon-based material with the polyaniline dispersion, the solid content is filtered and washed to prepare a polyaniline / carbon composite.
(4) A polyaniline / carbon composite is prepared by base treatment of a dispersion obtained by mixing a conductive polyaniline dispersion, a carbon-based material, and an aprotic solvent. The polyaniline / carbon composite can be isolated by filtering and washing the solid content in the dispersion.
(5) A precipitate formed by base treatment of the conductive polyaniline dispersion was filtered and washed to obtain a polyaniline powder in an undoped state. A polyaniline / carbon composite is prepared by mixing and dispersing the polyaniline powder and the carbon-based material. Alternatively, a polyaniline / carbon composite is prepared by mixing a dispersion obtained by dispersing and dissolving polyaniline powder in an aprotic solvent and a carbon-based material, and then removing the solvent.

  The conductive polyaniline dispersion, the polyaniline dispersion and / or the polyaniline powder and the carbon-based material may be mixed with the polyaniline dispersion and / or the powder mixed with the total amount of the carbon-based material, or the polyaniline dispersion. An example is a method in which a liquid and / or powder is mixed with a part of a carbon-based material to prepare a polyaniline / carbon composite in advance, and then the composite and the remaining carbon-based material are mixed.

  The base treatment method is not particularly limited as long as it is a method capable of dedoping the doped conductive polyaniline and neutralizing the sulfonic acid as the dopant, but it is not limited to the mixed dispersion or the complex. The method of making a sex substance act is mentioned. The basic substance is preferably a metal hydroxide such as ammonia water, sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide or calcium hydroxide; an amine such as methylamine, ethylamine or triethylamine; Examples include alkylammonium hydroxides such as methylammonium and tetraethylammonium hydroxide; hydrazine compounds such as hydrazine and phenylhydrazine; and hydroxylamine compounds such as diethylhydroxylamine and dibenzylhydroxylamine. The base treatment is a method of mixing the mixed dispersion or complex and the basic substance, a method of mixing the mixed dispersion or complex and water and / or an organic solvent in which the basic substance is dissolved, Examples thereof include a method of bringing the mixed dispersion or complex into contact with the gas of the basic substance. The organic solvent for dissolving the basic substance is not particularly limited as long as the basic substance can be dissolved, but aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as hexane, heptane, and cyclohexane, Halogenated hydrocarbons such as chloroform and dichloromethane, esters such as ethyl acetate and butyl acetate, alcohols such as methanol and ethanol, sulfoxides such as dimethyl sulfoxide, amides such as dimethylformamide, N-methyl-2-pyrrolidone and the like Can be mentioned.

  Examples of the aprotic solvent used in the above operations (3), (4) and (5) include formamides such as dimethylformamide and diethylformamide; sulfoxides such as dimethylsulfoxide and diethylsulfoxide; propylene carbonate, carbonic acid Examples thereof include carbonate esters such as dimethyl and diethyl carbonate; lactones such as γ-butyrolactone and γ-valerolactone; nitriles such as acetonitrile and propiononitrile; N-methyl-2-pyrrolidone and the like.

  The polyaniline or derivative thereof of the polyaniline / carbon composite of the present invention is formed by dedoping the dopant of the conductive polyaniline by the base treatment, but the dopant in the conductive polyaniline is not completely dedope. A thing may be used. The amount of dopant contained in the polyaniline formed by the base treatment is 0 to 0.3, preferably 0 to 0.1 in terms of a molar ratio per monomer unit of polyaniline.

  The mixing method used for preparing the polyaniline / carbon composite of the present invention can be prepared using a conventional mixer, but it is a sand mill, bead mill, ball mill, planetary ball mill, three roll mill, colloid mill, ultrasonic wave. A mixing and dispersing machine such as a homogenizer, a Henschel mixer, a jet mill, or a planetary mixer may be used.

  According to the present invention, an electrode material using the polyaniline / carbon composite as an active material is used and separated from the current collector (for example, platinum, copper, nickel, aluminum, conductive carbon material, conductive rubber material). Polar electrodes can be constructed. In the present invention, since a polyaniline which is a polymer compound is used, a binder is not always necessary, but it may be used. The binder that can be used is not particularly limited, and examples thereof include polyvinylidene fluoride, polytetrafluoroethylene, a fluoroolefin copolymer, carboxymethyl cellulose, polyvinyl alcohol, polyacrylic acid, polyvinyl pyrrolidone, and polymethyl methacrylate. In this way, an electric double layer capacitor having a high capacitance can be obtained. The polarizable electrode and the electric double layer capacitor can be produced by a general method except that a polyaniline / carbon composite is used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, it cannot be overemphasized that the scope of the present invention is not limited to these Examples.

Preparation of polyaniline toluene dispersion In 150 g of toluene, 12.6 g of aniline, 26.4 g of dodecylbensulfonic acid and 0.63 g of 2,4,6-trimethylaniline were dissolved, and then 100 g of distilled water in which 22.5 mL of 6N hydrochloric acid was dissolved. Was added. After adding 3.8 g of tetrabutylammonium bromide to this mixed solution and cooling to 5 ° C. or lower, 80 g of distilled water in which 33.9 g of ammonium persulfate was dissolved was added. After oxidative polymerization at 5 ° C. or less for 6 hours, 100 g of toluene and then a methanol / water mixed solvent (water / methanol = 2/3 (weight ratio)) were added and stirred. After the stirring, a polyaniline toluene dispersion was obtained by removing only the aqueous layer from the reaction solution obtained by separating the toluene layer into the aqueous layer. A part of the polyaniline toluene dispersion was sampled and the toluene was distilled off under vacuum. As a result, the dispersion contained a solid content of 12.9% by weight (polyaniline content 5% by weight). Further, when this dispersion was filtered with a filter having a pore size of 1.0 μm, it was not clogged. As a result of analyzing the particle size of the polyaniline particles in the dispersion with an ultrasonic particle size distribution analyzer (APS-100 manufactured by Matec Applied Sciences), the particle size distribution is monodisperse (peak value is 0.33 μm, half-value width is 0.17 μm). ) Furthermore, this dispersion was stable without agglomeration and precipitation even after 1 year at room temperature. From the elemental analysis, the molar ratio of dodecylbenzenesulfonic acid per aniline monomer unit was 0.45. The yield of the obtained polyaniline was 96%.

Preparation of Dedoped Polyaniline Powder After adding 500 mL of 2 mol / liter triethylamine methanol solution to 100 g of polyaniline toluene dispersion, the mixture was stirred and mixed for 5 hours. After the stirring, the precipitate was collected by mouth and washed with methanol. The filtrate and washing liquid at this time were colorless and transparent. The washed and purified precipitate was vacuum-dried to obtain a dedope polyaniline powder. 5 g of this polyaniline powder was added to and mixed with 95 g of N-methyl-2-pyrrolidone (NMP) to prepare a polyaniline N-methyl-2-pyrrolidone dispersion. As a result of analyzing the particle size of the polyaniline particles with an ultrasonic particle size distribution analyzer (APS-100 manufactured by Matec Applied Sciences), the particle size distribution is monodisperse (peak value is 0.31 μm, half width is 0.17 μm). I understood.

Polyaniline N-methyl-2-pyrrolidone dispersion (polyaniline NMP dispersion)
A polyaniline N-methyl-2-pyrrolidone dispersion was prepared by adding 5 g of dedoped polyaniline powder (average molecular weight 10,000, manufactured by Aldrich) to 95 g of N-methyl-2-pyrrolidone (NMP) and mixing them. As a result of analyzing the particle size of the polyaniline particles with an ultrasonic particle size distribution measuring device (APS-100 manufactured by Matec Applied Sciences), the particle size distribution is (A) peak (peak value 0.31 μm, half width 0.17 μm) and ( B) It consists of a peak (peak value 1.1 μm, half width 0.43 μm) and (C) peak (peak value 6.8 μm, half width 0.8 μm), and peak area ratio (A) :( B) :( C) was found to be 55: 40: 5. From the result of the particle size distribution, it was found that aggregates were mixed in the polyaniline N-methyl-2-pyrrolidone dispersion.

Preparation of polyaniline / carbon composite 1 To 20 g of polyaniline toluene dispersion, 1 g of conductive carbon black (manufactured by Lion Corporation, Ketjen Black ECP600JD) was added and mixed to obtain a mixed dispersion of conductive polyaniline and carbon black. 200 mL of a 2 mol / liter triethylamine methanol solution was added to the mixed dispersion, and the mixture was stirred and mixed for 5 hours. After the stirring, the precipitate was collected by mouth and washed with methanol. The filtrate and washing liquid at this time were colorless and transparent. A polyaniline / carbon composite 1 was prepared by vacuum drying the washed and purified precipitate.

Preparation of polyaniline / carbon composite 2 Polyaniline / carbon composite 2 was prepared by the same method for preparing polyaniline / carbon composite 1 except that 20 g of polyaniline toluene dispersion was changed to 30 g of polyaniline toluene dispersion.

Preparation of polyaniline / carbon composite 3 Polyaniline / carbon composite 3 was prepared by the same method for preparing polyaniline / carbon composite 1 except that 20 g of polyaniline toluene dispersion was changed to 40 g of polyaniline toluene dispersion.

Preparation of polyaniline / carbon composite 4 To 20 g of polyaniline toluene dispersion, 7.5 g of activated carbon (specific surface area 2000 m 2 / g, average particle size 10 μm) and 1 g of conductive carbon black (manufactured by Lion Corporation, Ketjen Black ECP600JD) are added. By mixing, a mixed dispersion of conductive polyaniline, activated carbon, and carbon black was obtained. 200 mL of a 2 mol / liter triethylamine methanol solution was added to the mixed dispersion, and the mixture was stirred and mixed for 5 hours. After the stirring, the precipitate was collected by mouth and washed with methanol. The filtrate and washing liquid at this time were colorless and transparent. Polyaniline / carbon composite 4 was prepared by vacuum drying the washed and purified precipitate.

Preparation of polyaniline / carbon composite 5 Polyaniline toluene dispersion, activated carbon (specific surface area 2000 m @ 2 / g, average particle size 10 .mu.m), conductive carbon black (manufactured by Lion Co., Ltd., Ketjen Black ECP600JD) were used in amounts of 30 g each The polyaniline / carbon composite 5 was prepared by the same method as the preparation of the polyaniline / carbon composite 4 except that 7.0 g and 1 g were obtained.

Preparation of polyaniline / carbon composite 6 1 g of the above dedoped polyaniline powder, 1 g of conductive carbon black (manufactured by Lion Corporation, Ketjen Black ECP600JD), and 20 g of N-methyl-2-pyrrolidone (NMP) are mixed in a mortar. A paste-like polyaniline / carbon composite 6 was prepared.

Preparation of polyaniline / carbon composite 7 1.5 g of the above-mentioned dedoped polyaniline powder, 1 g of conductive carbon black (manufactured by Lion Corporation, Ketjen Black ECP600JD), 20 g of N-methyl-2-pyrrolidone (NMP) By mixing, a pasty polyaniline / carbon composite 7 was prepared.

Preparation of Polyaniline / Carbon Composite 8 1 g of conductive carbon black (manufactured by Lion Corporation, Ketjen Black ECP600JD) was mixed with 20 g of the above polyaniline NMP dispersion to prepare a paste-like polyaniline / carbon composite 8.

Preparation of polyaniline / carbon composite 9 1 g of conductive carbon black (manufactured by Lion Corporation, Ketjen Black ECP600JD) was mixed with 30 g of the above polyaniline NMP dispersion to prepare a paste-like polyaniline / carbon composite 9.

Preparation of polyaniline / carbon composite 10 To 20 g of the above polyaniline NMP dispersion, 7.5 g of activated carbon (specific surface area 2000 m 2 / g, average particle size 10 μm), 1 g of conductive carbon black (manufactured by Lion Corporation, Ketjen Black ECP600JD) By mixing with a mortar, a pasty polyaniline / carbon composite 10 made of conductive polyaniline, activated carbon, and carbon black was prepared.

Preparation of polyaniline / carbon composite 11 1 g of polyaniline powder (average molecular weight 10,000, manufactured by Aldrich), 1 g of conductive carbon black (manufactured by Lion Corporation, Ketjen Black ECP600JD), N-methyl-2-pyrrolidone (NMP) 20 g was mixed with a mortar to prepare a pasty polyaniline / carbon composite 11.

Preparation of polyaniline / carbon composite 12 20 g of polyaniline sulfonic acid aqueous solution (manufactured by Aldrich, 5% aqueous solution) and 1 g of conductive carbon black (manufactured by Lion Co., Ltd., Ketjen Black ECP600JD) are mixed in a mortar, and pasty polyaniline / Carbon composite 12 was prepared.

Preparation of electrode 1 Polyaniline / carbon composite 1 (2 g), activated carbon (specific surface area 2000 m 2 / g, average particle size 10 μm) (7.5 g), and carboxymethyl cellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1% aqueous solution) )) (0.5 g) was sufficiently mixed and dispersed in a mortar, and further mixed with a mortar while gradually adding water (30 g) to obtain a paste. This paste was applied to an aluminum foil (film thickness 30 μm) so that the thickness of the active material layer was 100 μm. After drying at 150 ° C. for 24 hours, vacuum drying was performed at 150 ° C. for 2 hours. After this sheet-like electrode was pressure-treated at 20 MPa, it was cut out with a size of 1 cm × 1 cm to produce an evaluation electrode 1.

Preparation of electrode 2 Polyaniline / carbon composite 2 (2.5 g), activated carbon (specific surface area 2000 m 2 / g, average particle size 10 μm) (7.0 g) and carboxymethyl cellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1 % Aqueous solution)) (0.5 g) was sufficiently mixed and dispersed in a mortar, and further mixed with a mortar while gradually adding water (30 g) to form a paste. An evaluation electrode 2 was produced in the same manner as the production method of the electrode 1 of Example 1 except that this paste was used.

Preparation of electrode 3 Polyaniline / carbon composite 3 (3.0 g), activated carbon (specific surface area 2000 m @ 2 / g, average particle size 10 .mu.m) (6.5 g) and carboxymethyl cellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1 % Aqueous solution)) (0.5 g) was sufficiently mixed and dispersed in a mortar, and further mixed with a mortar while gradually adding water (30 g) to form a paste. An evaluation electrode 3 was produced in the same manner as the production method of the electrode 1 of Example 1 except that this paste was used.

Preparation of Electrode 4 After polyaniline / carbon composite 4 (9.5 g) and carboxymethylcellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1% aqueous solution)) (0.5 g) were sufficiently mixed and dispersed in a mortar, While gradually adding water (30 g), the mixture was further mixed in a mortar to form a paste. An evaluation electrode 4 was produced by the same method as the production method of the electrode 1 of Example 1 except that this paste was used.

Preparation of Electrode 5 After polyaniline / carbon composite 5 (9.5 g) and carboxymethylcellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1% aqueous solution)) (0.5 g) were sufficiently mixed and dispersed in a mortar, While gradually adding water (30 g), the mixture was further mixed in a mortar to form a paste. An evaluation electrode 5 was produced by the same method as the production method of the electrode 1 of Example 1 except that this paste was used.

Preparation of electrode 6 Polyaniline / carbon composite 6 (22 g), activated carbon (specific surface area 2000 m 2 / g, average particle size 10 μm) (7.5 g), carboxymethyl cellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1% aqueous solution) )) (0.5 g) was sufficiently mixed and dispersed in a mortar, and further mixed with a mortar while gradually adding water (20 g) to obtain a paste. An evaluation electrode 6 was produced in the same manner as the production method of the electrode 1 of Example 1 except that this paste was used.

Preparation of electrode 7 Polyaniline / carbon composite 7 (22.5 g), activated carbon (specific surface area 2000 m 2 / g, average particle diameter 10 μm) (7.0 g), carboxymethyl cellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1 % Aqueous solution)) (0.5 g) was sufficiently mixed and dispersed in a mortar, and further mixed with a mortar while gradually adding water (20 g) to form a paste. An evaluation electrode 7 was produced in the same manner as the production method of the electrode 1 of Example 1 except that this paste was used.

Preparation of electrode 8 Activated carbon (specific surface area 2000 m 2 / g, average particle size 10 μm) (8.5 g), conductive carbon black (manufactured by Lion Corporation, Ketjen Black ECP600JD) (1.0 g), carboxymethylcellulose sodium salt ( Aldrich, viscosity 1500-3000 cP (1% aqueous solution)) (0.5 g) was sufficiently mixed and dispersed in a mortar, and further mixed with a mortar while gradually adding water (30 g) to obtain a paste. An evaluation electrode 8 was produced by the same method as the production method of the electrode 1 of Example 1 except that this paste was used.

Preparation of electrode 9 Polyaniline / carbon composite 8 (22 g), activated carbon (specific surface area 2000 m 2 / g, average particle diameter 10 μm) (7.5 g), carboxymethyl cellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1% aqueous solution) )) (0.5 g) was sufficiently mixed and dispersed in a mortar, and further mixed with a mortar while gradually adding water (20 g) to obtain a paste. An evaluation electrode 9 was produced in the same manner as the production method of the electrode 1 of Example 1 except that this paste was used.

Preparation of electrode 10 Polyaniline / carbon composite 9 (31 g), activated carbon (specific surface area 2000 m 2 / g, average particle diameter 10 μm) (7.0 g), carboxymethyl cellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1% aqueous solution) )) (0.5 g) was sufficiently mixed and dispersed in a mortar, and further mixed with a mortar while gradually adding water (20 g) to obtain a paste. An evaluation electrode 10 was produced by the same method as the production method of the electrode 1 of Example 1 except that this paste was used.

Preparation of electrode 11 Polyaniline / carbon composite 10 (28.5 g), carboxymethylcellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1% aqueous solution)) (0.5 g) were mixed and dispersed in a mortar, then water (20 g) was gradually added and further mixed in a mortar to make a paste. An evaluation electrode 11 was produced in the same manner as the production method of the electrode 1 of Example 1 except that this paste was used.

Preparation of electrode 12 Polyaniline / carbon composite 11 (22 g), activated carbon (specific surface area 2000 m 2 / g, average particle diameter 10 μm) (7.5 g), carboxymethyl cellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1% aqueous solution) )) (0.5 g) was mixed and dispersed in a mortar, and further mixed in a mortar while gradually adding water (20 g) to obtain a paste. An evaluation electrode 12 was produced in the same manner as the production method of the electrode 1 of Example 1 except that this paste was used.

Preparation of electrode 13 Polyaniline / carbon composite 12 (21 g), activated carbon (specific surface area 2000 m 2 / g, average particle diameter 10 μm) (7.5 g), carboxymethyl cellulose sodium salt (manufactured by Aldrich, viscosity 1500-3000 cP (1% aqueous solution) )) (0.5 g) was mixed and dispersed in a mortar, and further mixed in a mortar while gradually adding water (20 g) to form a paste. An evaluation electrode 13 was produced by the same method as the production method of the electrode 1 of Example 1 except that this paste was used.

Measurement of Specific Capacity In Examples 1 to 7 and Comparative Examples 1 to 6, an electric double layer capacitor was produced by the following method, and the specific capacity per electrode active material was determined.
Electric double layer using 1M tetraethylammonium tetrafluoroborate propylene carbonate solution as an electrolytic solution, with the prepared electrodes for evaluation 1 to 12 facing positive and negative electrodes through glass fiber filter paper (Whatman filter paper GF / A) A capacitor was produced. The charge / discharge test of the electric double layer capacitor was performed using a charge / discharge tester (HJ1001SM8A manufactured by Hokuto Denko). Charging was performed with a constant current of 2 mA, and after the voltage reached 2.5 V, charging was performed with constant voltage charging for 1 hour. Discharging was performed at a constant current of 2 mA, and the final voltage was 0V. The charge / discharge test of each capacitor was repeated 1000 times, and the specific capacity per electrode active material weight was determined from the discharge curve at the 10th cycle. Further, the specific capacity per weight of the electrode active material was determined from the discharge curve at the 1000th cycle, and the ratio with the specific capacity determined from the discharge curve at the 10th cycle was determined as cycle characteristics (= specific capacity determined from the discharge curve at the 1000th cycle). / Specific capacity obtained from the discharge curve at the 10th cycle) and used as an index of electrode stability.

  Table I summarizes the composition ratio of the materials contained in the electrodes 1 to 13, the specific capacity of each electrode determined from the electric double layer capacitor using the electrodes 1 to 13, and the cycle characteristics.

In Examples 8 to 10 and Comparative Examples 7 to 10, electric double layer capacitors were produced by the following method, and the specific capacity per electrode active material was determined.
The above-prepared electrodes for evaluation 1 to 3, 8 to 10 and 13 are opposed to each other through glass fiber filter paper (Whatman filter paper GF / A) with both positive and negative electrodes, and an electric double layer using a 15 wt% sulfuric acid aqueous solution as an electrolyte. A capacitor was produced. The charge / discharge test of the electric double layer capacitor was performed using a charge / discharge tester (HJ1001SM8A manufactured by Hokuto Denko). Charging was performed with a constant current of 2 mA, and after the voltage reached 1.0 V, charging was performed with constant voltage charging for 1 hour. Discharging was performed at a constant current of 2 mA, and the final voltage was 0V. The charge / discharge test of each capacitor was repeated 1000 times, and the specific capacity per electrode active material weight was determined from the discharge curve at the 10th cycle. Further, the specific capacity per weight of the electrode active material was determined from the discharge curve at the 1000th cycle, and the ratio with the specific capacity determined from the discharge curve at the 10th cycle was determined as cycle characteristics (= specific capacity determined from the discharge curve at the 1000th cycle). / Specific capacity obtained from the discharge curve at the 10th cycle) and used as an index of electrode stability.

  Table II shows composition ratios of materials contained in electrodes 1 to 3, 8 to 10, 13, specific capacities of electrodes obtained from electric double layer capacitors using electrodes 1 to 3, 8 to 10, and 13, cycles The characteristics are summarized.

  As described above, the electric double layer capacitors (Examples 1 to 10) using the polyaniline / carbon composite composed of the polyaniline and the carbon-based material formed by dedoping the conductive polyaniline dispersion liquid are only activated carbon electrodes ( Comparative Examples 1 and 7), polyaniline / carbon composites 8 to 11 (Comparative Examples 2 to 5 and Comparative Examples 8 to 8) composed of dedope-treated polyaniline powder (commercial product: emeraldine base type polyaniline) and a carbon-based material 9) Compared with the polyaniline / carbon composite 12 (Comparative Examples 6 and 10) comprising a polyaniline sulfonic acid aqueous solution and a carbon-based material, it can be seen that the specific capacity and cycle characteristics are excellent.

  As described above, the polyaniline / carbon composite according to the present invention can obtain an electric double layer capacitor excellent in high capacitance and cycle characteristics by dedoping, for example, for memory backup of a mobile phone or the like. It is suitable for use as an emergency power source in a power source / computer, an energy storage device in a solar power generation system, a regenerative braking energy storage device in an electric-gasoline hybrid vehicle, and the like.

Claims (3)

Polyaniline or a derivative thereof, activated carbon, ketjen black, a polyaniline / carbon composite body formed by compounding a carbon-based material selected from acetylene black, and furnace black, the polyaniline or a derivative thereof, a non-polar organic solvent An electrode material for an electric double layer capacitor using a polyaniline / carbon composite, which is obtained by dedoping conductive polyaniline or a derivative thereof dispersed in a base. The electrode material for an electric double layer capacitor according to claim 1, wherein an amount of the polyaniline or a derivative thereof is 1 to 300 parts by weight with respect to 100 parts by weight of the carbon-based material . An electric double layer capacitor having a polarizable electrode using the electrode material according to claim 1 .