JP2000103610A - Production of carbon powder and carbonaceous material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a carbon powder useful as a polarizing electrode excellent in capacity characteristics of a capacitor by adding a thermally volatile substance capable of generating a gas at a specific temperature and a foaming agent to a thermosetting resin, foaming the thermosetting resin baking the resultant foam in a nonoxidizing atmosphere and pulverizing the baked resin. SOLUTION: A thermally volatile substance capable of generating a gas at a temperature in the region of 150-400 deg.C and a foaming agent are added to a thermosetting resin comprising a resol type phenol resin. Polyethylene, polypropylene etc., are used as the thermally volatile substance and the ratio thereof based on the thermosetting resin (solid content) is 5-50 wt.%. Trichloromonofluoromethane, etc., are used as the foaming agent in an amount of about 5-50 pts.wt. based on 100 pts.wt. of the thermosetting resin (solid content). The resultant mixture is then molded, foamed and cured at about 60-90 deg.C baked at 550-900 deg.C in a nonoxidizing atmosphere and subsequently pulverized. Thereby, a carbon powder having 2-20 μm average particle diameter and 200-800 m2/g specific surface area is produced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a carbon material such as a carbon powder and a polarizable electrode using the carbon powder. Polarizing electrodes are capacitors, secondary batteries, and electric double layers formed at the interface between the electrode surface and the electrolyte.
It is used for electrochromic displays and the like.

[0002]

2. Description of the Related Art The basic structure of an electric double layer capacitor is shown in FIG. In the figure, reference numeral 1 denotes a polarizable electrode containing an electrolytic solution, and a pair of electrodes is separated by an electrically insulating and ion-permeable separator 2. The periphery of the polarizable electrode 1 is hermetically sealed with a sealing material 3 to form one unit of capacitor (single cell). And this single cell is impervious,
In addition, a large number of them are stacked via the conductive current collecting plate 4 and used for use. This type of large-capacity electric double-layer capacitor is also called a capacitor. Electric double layer capacitors are roughly classified into two types depending on the type of electrolyte. One type uses an aqueous solution of sulfuric acid as an electrolyte, and is generally called an aqueous capacitor or a sulfuric acid-based capacitor. Another one
One type is called an organic capacitor, and a quaternary ammonium salt / propylene carbonate solution or the like is used as an electrolyte. Polarizable electrodes (hereinafter simply referred to as "electrodes") used in electric double-layer capacitors, etc., need to have a certain surface area to increase the capacitance per unit volume and unit weight (hereinafter referred to as "capacity"). For this reason, activated carbon powder, activated carbon fiber and the like are often used.

[0003] As activated carbon for electrodes, coconut shell, sawdust, phenol resin, polyvinylidene chloride resin and other activated carbon are used as starting materials, and the form of the electrode is as follows. An electrode in which activated carbon powder was made into a paste with a sulfuric acid aqueous solution (JP-A-62-130506 and JP-A-63-244609;
JP-A-2-174210). With this electrode, the contact resistance between the activated carbon powders increases, and as a result, the ohmic resistance of the entire electrode increases, and the capacity loss due to the resistance when used with a large current increases. A sintered electrode (JP-A-7-249551) obtained by preliminarily heat-treating polyvinylidene chloride and then sintering it in a mold under pressure has high capacity characteristics, but has a problem in productivity. There is a method in which a porous carbon molded body is activated and impregnated with an electrolytic solution (Japanese Patent Application Laid-Open No. 2-297915), but this method does not provide sufficient capacity characteristics. A carbon fiber electrode (JP-A-64-82514) in which an electrolyte is impregnated using a woven fabric of activated carbon fibers or the like is not practical because the raw material cost is high.

[0004] The activated carbon powder mixed sheet is cured together with the phenol resin, fired, and steam activated,
A method for producing a polarizable electrode material for an electric double layer is disclosed (JP-A-5-121271, JP-A-6-26779).
4). This method is excellent in productivity and low in ohmic resistance of the electrode, and is an excellent method for producing uniform quality. However, when the content of activated carbon powder in the sheet is 50% by weight or more, the phenol resin impregnation step However, the separation of the activated carbon powder from the sheet and the decrease in the strength of the electrode after firing caused problems, and it was virtually impossible to produce an electrode using a mixed sheet having an activated carbon powder content of 50% by weight or more. This restriction on the amount of the activated carbon powder hindered the improvement of the capacity characteristics. Activated carbon powder currently used for an electrode for an electric double layer capacitor is extremely expensive, unlike activated carbon used in conventional adsorption applications, and has a high productivity (JP-A-5-1212).
1271, Japanese Patent Application Laid-Open No. 6-267794), a great deal of cost is required for the production of electrodes, which hinders practical application to in-vehicle applications and the like. A method of producing a glassy carbon powder by firing and crushing a foam obtained from a thermosetting resin in a non-oxidizing atmosphere, or crushing and sintering the foam has been proposed (Japanese Patent Laid-Open No. Hei 3 (1994)). 164416).

[0005]

[0005] Recently, electric vehicles (EVs, electric veins) have been actively developed due to environmental problems. However, there is no sign of a full-fledged EV driven by a secondary battery alone due to the lack of infrastructure such as a charging facility (a convenient charging facility such as a gas station). Under these circumstances, HEV, which is a more realistic hybrid system with a gasoline engine, has begun to be partially commercialized prior to EV. The HEV is a hybrid system with a secondary battery, a large-capacity capacitor, and the like, and can reduce gasoline consumption to about half that of a conventional vehicle driven by a gasoline engine alone. The large-capacity capacitor for HEV is called an electric double layer capacitor or a capacitor, and further improvement in performance and cost reduction are demanded from the industry. An object of the present invention is to provide a method for producing a polarizable electrode used for a large-capacity electric double-layer capacitor and the like, which can realize performance improvement and cost reduction, other carbon materials, and a carbon powder used for these raw materials and the like. It is in.

[0006]

Means for Solving the Problems As a result of further study on the above-mentioned method, the present inventors added a substance generating gas at a specific temperature and a foaming agent to a thermosetting resin and caused the foam to foam.
The inventors have found that a polarizable electrode using a carbon powder obtained from the foam has more excellent capacitor capacity characteristics, and reached the present invention. That is, the basic configuration of the method for producing the carbon powder, the carbon material, and the polarizable electrode of the present invention is as follows.

(1) 150-400 ° C. for thermosetting resin
A heating volatile substance and a foaming agent that generates a gas in the temperature range described above are added and foamed, and the obtained foam is fired and crushed in a non-oxidizing atmosphere, or the foam is crushed and fired in a non-oxidizing atmosphere. A method for producing carbon powder. (2) A method for producing a carbon material, comprising impregnating a sheet containing carbon powder and a fibrous substance obtained by the method of the above (1) with a thermosetting resin and firing the sheet. (3) The method for producing a carbon material according to the above (2), wherein the carbon material is a polarizable electrode.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The thermosetting resin used in the above-mentioned method for producing carbon powder is a phenol resin, a furan resin or the like, and is an uncured liquid. Of these, phenolic resins are preferred. As the phenol resin, both the resol type and the novolak type can be cured, but the resol type is preferable in terms of the ease of production of the foamed molded article.

As the blowing agent used in the present invention, any organic or inorganic blowing agent can be used as long as it is used as a blowing agent for synthetic resins such as phenolic resins. Boiling point is 5 from the viewpoint of foaming efficiency
Organic volatile blowing agents in the range of 60 ° C. are preferred. For example, trichloromonofluoromethane, dichloromonofluoromethane, methylene chloride, trichlorotrifluoroethane, acetone, ether, petroleum ether, pentane and the like can be mentioned. The amount of the organic volatile foaming agent is based on 100 parts by weight of the thermosetting resin (solid content).
5 to 50 parts by weight are suitable. When it is less than this range, it is difficult to obtain a sufficient specific surface area, and when it is more than this, there are problems such as bulkiness, handling becomes difficult and the yield is low, but it is out of this range. But the difficulty of operation increases, but not impossible.

In the present invention, the substance to be heated and volatilized is 150 to 4
It is a substance that generates gas in the temperature range of 00 ° C. The gas is generated by volatilization or thermal decomposition of the substance in the above temperature range. In the process of foaming and carbonizing the foam due to the presence of the heating volatile substance, the gas generated from the heating volatile substance inside the foam not only increases the specific surface area of the carbon powder but also generates suitable pores that contribute to the capacity characteristics. It is thought to be. There is no effect if the gas generation temperature in the firing process is too low or too high, and it is necessary to generate gas in the range of 150 to 400 ° C. At 400 ° C., most of the gas is gasified and the residual ratio is preferably small. Preferably, the residual ratio at 400 ° C. (400 ° C. with respect to the weight before gas generation)
Is 35% by weight or less).

[0011] Examples of the heat volatile substances include polyethylene, polypropylene, polymethylpentene, polybutene, polystyrene, polybutadiene, polyvinyl chloride, and the like.
Polyvinyl acetate, polychlorinated polyvinyl chloride, polyvinylidene chloride, chlorinated polypropylene, chlorinated polyethylene,
Polyester, zinc chloride, iron chloride and the like can be used. These are generally used in powder form. The ratio of the heating volatile substance to the thermosetting resin (solid content) before firing is 5 to 5
0% by weight is desirable. This is because even if the heating volatile substance exceeds 50% by weight, no further improvement in the capacity characteristics is observed.
The carbon yield after firing with respect to the raw material foam is reduced,
This is because productivity decreases. If the amount is less than 5% by weight, the effect is not exhibited.

A surfactant may be added to the above-mentioned raw material mixture in order to smoothly recommend a curing agent and a foaming action of the thermosetting resin and to uniformly disperse pores of an appropriate size. As the curing agent, those capable of curing the thermosetting resin as quickly as possible are preferable, and usually a strong acid such as an organic acid or an inorganic acid is convenient. For example, phenolsulfonic acid, benzenesulfonic acid, paratoluenesulfonic acid, phosphoric acid, sulfuric acid, boric acid and the like can be used. The amount used depends on the type of the curing agent, but is generally about 1 to 30 parts by weight based on 100 parts by weight of the thermosetting resin (solid content). Examples of the surfactant include a silicon-based surfactant such as a polydimethylsiloxane-polyalkylene oxide-block copolymer and a vinylsilane-polyalkylene polyol copolymer.

According to a known method, the raw material mixture is injection-molded into, for example, a panel press, and heated to about 60 to 90 ° C. to foam and harden. The foam is fired as it is in a non-oxidizing atmosphere, or fired in the atmosphere after pulverization. The firing temperature is not particularly limited as long as it is equal to or higher than the carbonization temperature of the thermosetting resin. However, if the firing temperature is too high, the specific surface area of the obtained carbon powder decreases.

According to the above method, the average particle size is 2 to 20 μm (the measuring method is a laser diffraction method; the same applies hereinafter) and the specific surface area (B
ET method. (The same applies hereinafter.) A carbon powder of 200 to 800 m ² / g is obtained. The carbon powder is mainly a carbide of a thermosetting resin, and is generally called a glassy carbon powder. This carbon powder is suitable as a raw material for a polarizable electrode, but can be used as other activated carbon powder.

Next, a method for producing a carbon material such as a polarizable electrode using the carbon powder will be described. The method for producing the carbon material of the present invention is a method in which a sheet containing the carbon powder and the fibrous material obtained as described above is impregnated with a thermosetting resin and calcined. If not, it is possible to impregnate the thermosetting resin and carbon powder into a sheet such as nonwoven fabric,
The following papermaking method is most preferred. The present inventor has proposed a papermaking method (JP-A-5-121271, which is considered to be most suitable from the viewpoint of productivity and characteristics as a sheet in a method of producing a carbon material.
6-267794), the following findings were obtained.

1) Activated carbon powder having a smaller specific surface area is easier to make into a papermaking sheet, and a papermaking sheet with a high blending ratio can be obtained. 2) Activated carbon having a large specific surface area (1000 m ² / g or more) not only makes it difficult to make it into a papermaking sheet, but also does not increase the density, so that the unit volume which is regarded as important for in-vehicle use and the like is not considered. A high capacity cannot always be obtained at a hit. The reason for this is that a large amount of activated carbon powder is to be made into a papermaking sheet, for example, as described in JP-A-53-35712.
Although additives such as a cationic polymer, an anionic polymer, and aluminum sulfate as shown in JP-A-57-162630) are required, a large specific surface area conventionally used mainly for capacitors is required. When the activated carbon (1000 m ² / g or more) is used, it is considered that these additives are absorbed by the activated carbon powder and become difficult to function. 1) and 2) above
The most preferred carbon powder that satisfies
８００800 m ² / g carbon powder.

Hereinafter, a method for producing a carbon material by a papermaking method will be described in detail. The average particle size of the carbon powder is 2 to 20.
μm is desirable. The smaller the particle size, the more advantageous in the capacity characteristics. However, if the particle size is less than 2 μm, the pulverization cost increases and the particles are aggregated and the like, making uniform paper making difficult. The capacity characteristics are not further improved. On the other hand, if it exceeds 20 μm, the apparent surface area becomes small, so that the capacity characteristics are not sufficient, and sedimentation tends to occur during paper making, and the paper making properties deteriorate.
Next, a papermaking sheet is prepared from the carbon powder and the fibrous substance. The most suitable fibrous substance for holding the carbon powder in the papermaking sheet is preferably a substance mainly composed of fibrillable fibers. Specifically, cellulosic fibers, polyolefin fibers, acrylic fibers, etc.
It is preferable to mainly use wood pulp when judging comprehensively such as cost and papermaking properties. Papermaking involves dispersing carbon powder, fibrous substances, and additives in water, forming a slurry, and using a paper machine such as a long net or a circular net. In addition, glass fiber, meta- or para-type aramid fiber, alumina fiber, and the like are used as a fiber for reinforcing the strength of the papermaking sheet to improve the handleability of the papermaking sheet, but these retain carbon powder in the sheet. The amount of addition is preferably 20% by weight or less in the papermaking fiber, since the force is reduced.

The mixing ratio of carbon powder in papermaking is 50 to 9
5% by weight is preferred. If it is less than 50% by weight, the capacity characteristics are low, and if it exceeds 95% by weight, papermaking becomes difficult. Next, the papermaking sheet is impregnated with a thermosetting resin in an uncured liquid state. A highly conductive carbon filler, for example, graphite powder, may be mixed in the resin liquid in order to reduce the electric characteristics, that is, the electric resistance of the carbon material. To impregnate the resin, the amount of impregnation is adjusted by immersing the papermaking sheet in a solution of the resin, then pulling it up and passing it between rolls as necessary. The resin impregnation amount is preferably 3 to 30% by weight of the thermosetting resin (solid content). If the amount is less than 3% by weight, the binder function of the thermosetting resin is not sufficiently exhibited. If the amount exceeds 30% by weight, the sheet impregnated with the resin liquid in which the thermosetting resin blocks the pores of the carbon powder and has insufficient capacity is as follows. And dried at about 100 to 180 ° C. to obtain a prepreg sheet. When the prepreg sheet is thick, the resin material can be cured and fired as it is, and can be used as a carbon material. However, it is preferable that a plurality of thin sheets are laminated, pressed, cured, and fired. When the sheet is thick, it is difficult to make paper, and it is difficult to impregnate the resin liquid efficiently and uniformly. The prepreg sheet is heated to about 150 to 200 ° C. to cure the resin. At this time, stainless steel plate,
It is preferable to compress the film to about 5 to 70 kg / cm ² by sandwiching it between aluminum plates or the like. The compression prevents the generation of large pores, and in the case of lamination, the adhesion between the sheets is improved, and the performance is improved by increasing the bulk density of the carbon material. The cured sheet is then carbonized and fired under an inert atmosphere. For example, it is preferable that the firing sheet is sandwiched between graphite plates so as to be baked at a uniform temperature. The firing temperature is preferably from 500 to 900C. If the temperature is lower than 500 ° C., the ohmic resistance of a carbon material, for example, an electrode increases, and IR
(Current / voltage) drop causes a drop in capacitance characteristics. When the temperature exceeds 900 ° C., the pores of the carbon powder are blocked, and as a result, the capacity characteristics are reduced.

It is also possible to further activate the carbon material obtained above. In particular, when used for an organic capacitor, the activation treatment is effective. This is presumed that, in the case of organic capacitors, the pores in the carbon powder are too small, and thus it is effective to increase the pore diameter by activation treatment. Activation methods include UV irradiation activation, glow discharge activation, halogen gas activation, sulfuric acid, KOH, ZnC
chemical activation by l _2, etc., there is a steam-activated, etc. Various methods, steam-activated if the carbon material is the electrode is preferred over the properties improved. However, in order to bring out more advanced electrode characteristics, the possibility of activating them repeatedly, for example, combining halogen gas activation or chemical activation with water vapor activation is sufficiently conceivable. In the present invention, steam activation can be performed as follows. The condition of steam activation is 750-
It is preferable that the temperature is 1100 ° C. and the time is 20 to 600 minutes. Temperature 7
If the temperature is less than 50 ° C. and the time exceeds 600 minutes, the treatment time is too long to be practical. If the temperature exceeds 1100 ° C. and the time is less than 20 minutes, non-uniformity occurs and strength, electric resistivity, etc. The physical properties of the material decrease.

The carbon material obtained by the production method of the present invention becomes excellent electrodes (polarizable electrodes used for electric double layer capacitors, secondary batteries, electrochromic displays, etc.) as they are. In addition, it can be used as an electrode other than the polarizable electrode, for example, for a fuel cell or the like.

[0021]

The present invention will be described in detail with reference to the following examples. (Example 1) Liquid phenol resin (BRL120-Z, manufactured by Showa Polymer Co., Ltd.), silicon-based surfactant (Co., Ltd.)
Shin-Etsu Chemical F-305, block copolymer of dimethylpolysiloxane and polyether), and Freon-113 (1,1,2-trifluoro-1,2,2-
Trichloroethane) and the powder of the volatile substance in Table 1 were sufficiently mixed by a mixer, and then an aqueous solution containing 63% by weight of phenolsulfonic acid was added as a curing agent. After further mixing, the panel press was previously heated to 80 ° C. The mixture was injected into the flask and fired, and a curing reaction was performed for 10 minutes to remove the mold.
Table 1 shows the addition ratio of each component. The foam was carbonized and fired at 700 ° C. for 3 days in a non-oxidizing atmosphere. The fired body was pulverized with a ball mill to obtain a carbon powder having an average particle size of 8 μm. The specific surface area of this carbon powder is as shown in Table 1. In Table 1, A and B are the carbon powders of the present invention, and C is the carbon powder in the comparative example in which no heat volatile substance is used.

Examples 2 to 7 Next, electrodes were prepared using the carbon powders shown in Table 1. First, carbon powder having the proportions shown in Table 2, pulp, CMC (carboxymethylcellulose) as an additive, and a small amount of polyamidoamine were dispersed in water, and a papermaking sheet was obtained by papermaking with a circular paper machine. This papermaking sheet is applied to a phenol resin solution (Showa High Polymer Co., Ltd.)
BRL120-Z) and dried at 120 ° C. for 1 minute to obtain a prepreg sheet. The degree of dilution of the phenol resin solution was adjusted so that the phenol resin impregnation amount was 10% by weight according to the following equation. Phenolic resin impregnation amount calculation formula: Phenolic resin solid content / (papermaking sheet + phenol resin solid content) × 100 (% by weight) Eight of these prepreg sheets were laminated, and a Teflon-based release agent (trade name: DAIFREE) was applied. Sandwiched between stainless steel plates,
It was pressurized at 50 kg / cm ² and heat-cured at 155 ° C. for 30 minutes to obtain a green molded sheet. These green molded sheets were sandwiched between graphite plates and carbonized and fired at 750 ° C. for 3 days in a non-oxidizing atmosphere. The sheet had a good appearance.

A part of these carbon sheets was set in a steam activation furnace, and 40 ° C. saturated steam bubbled with N ₂ gas was introduced into a furnace adjusted to a predetermined temperature of 850 ° C.
A steam activation treatment was performed for 3 hours. From the obtained carbon sheet, a 10 mm square plate-shaped electrode was cut out, each physical property was measured, and a cell having the basic structure shown in FIG. Was examined. The cell performance was measured using a 30% by weight sulfuric acid electrolytic solution, and a 2 molar concentration of tetraethylmethylammonium tetrafluoride boron / propylene carbonate solution (TEMABF4 / PC, Sollite CAG manufactured by Mitsubishi Chemical Corporation) as an organic electrolytic solution. Was examined. The separator used was a glass filter GA100 manufactured by Advantech Co., Ltd., and the current collector plate was a carbon plate manufactured by Showa Denko KK (trade name: SG).
-3, thickness 0.6 mm). As a sealing material, a packing sheet made of Teflon (manufactured by Daikin Industries, Ltd., PF
A) was cut out and used.

The electric double layer capacitor assembled in this manner is sealed in a glass container, and approximately 5 k
The capacity performance was examined in a state of being tightened at a pressure of g / cm ² . The internal resistance was evaluated by an equivalent series resistance (ESR) measured by passing a constant current of 1 KHz and 10 mA through the electric double layer capacitor. The capacity was measured using a charge / discharge tester manufactured by Hokuto Denko Co., Ltd., and after a constant current charge of 0.002 A, the battery was discharged at a constant current of 0.002 A. By calculating the capacitance from the time required for the voltage to drop to 0.1 V or from 2.4 V to 0.1 V in the case of an organic system, the capacitance is divided by the total volume of a pair of electrodes. The capacity per unit volume was calculated. Table 3 shows the characteristic measurement results.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Table 3]

[0028]

According to the present invention, a carbon powder can be obtained with higher productivity and lower cost than conventional activated carbon powder. A polarizable electrode having high capacity characteristics can be obtained from the carbon powder, and the strength of the electrode is also improved. When a sheet is obtained from the carbon powder and the fibrous material by a papermaking method, a large amount of the carbon powder can be contained, and thus the polarizable electrode manufactured from the sheet can have a high capacity. In the paper making method, although the paper making sheet is thin,
It is easy to handle and has good productivity. Further, an electrode formed by a papermaking method can obtain uniform characteristics without performing surface processing in the thickness direction, and thus can be used as an electrode only by cutting. In addition to reducing processing costs, it is possible to minimize the consumption of raw materials.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a basic configuration of an electric double layer capacitor.

[Explanation of symbols]

 1 minute polarity electrode 2 separator 3 sealing material 4 current collector

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuichi Kamijo 6850, Omachi, Omachi, Nagano Prefecture Showa Denko Co., Ltd. Omachi Plant F-term (reference) 4G046 CA04 CB01 CB02 CB03 CB05 CB06 CB09 CC03 HA02 HA03 HB02 HB03 HB05 HC08 HC09

Claims (12)

[Claims] 1. A thermosetting resin is added with a heating volatile substance generating a gas in a temperature range of 150 to 400 ° C. and a foaming agent, foamed, and the obtained foam is fired and pulverized in a non-oxidizing atmosphere. Or a method for producing carbon powder, characterized in that the foam is pulverized and then fired in a non-oxidizing atmosphere. 2. The method according to claim 1, wherein the heating volatile substance is in a non-oxidizing atmosphere.
The method for producing carbon powder according to claim 1, wherein the substance has a residual ratio at 35 ° C of 35% by weight or less. 3. The method for producing carbon powder according to claim 1, wherein the amount of the volatile substance is 5 to 50% by weight based on the thermosetting resin. 4. The method for producing carbon powder according to claim 1, wherein the firing temperature is 550 to 900 ° C. 5. The carbon powder has an average particle size of 2 to 20 μm.
m and a specific surface area of 200 to 800 m ² / g.
5. The method for producing a carbon powder according to any one of items 4 to 4. 6. The method for producing carbon powder according to claim 1, wherein the carbon powder is for a polarizable electrode. 7. A method for producing a carbon material, comprising impregnating a sheet containing carbon powder and a fibrous substance obtained by the production method according to claim 1 with a thermosetting resin and firing the sheet. 8. The method for producing a carbon material according to claim 7, wherein the sheet is a papermaking sheet. 9. The method for producing a carbon material according to claim 7, wherein the amount of the carbon powder is 50 to 95% by weight, and the impregnation amount of the thermosetting resin is 3 to 30% by weight. 10. The method for producing a carbon material according to claim 7, wherein sheets impregnated with a thermosetting resin are laminated and fired at 500 to 900 ° C. 11. A method for producing a carbon material, comprising subjecting the carbon material obtained by the method according to claim 7 to a steam activation treatment. 12. The method according to claim 7, wherein the carbon material is a polarizable electrode.
12. The method for producing a carbon material according to items 11 to 11.