JP2000040644A - Electric double layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric double layer capacitor which has practical and high capacitance in which internal resistance is reduced, and a polarizable electrode of solid carbon which is excellent in mechanical strength and durability, and applies non-aqueous electrolytic solution having high capacitance, high output and high energy density to electrolyte. SOLUTION: Carbonaceous material exhibiting excellent conductivity of at most 0.5 Ω.cm is used as main component, and solid carbon is formed which has specific surface area of at least 700 m2/g and at most 2000 m2/g measured by a nitrogen adsorption method (BET method) with fines holes formed by activation treatment. A polarizable electrode is constituted of the solid carbon. This electric double layer capacitor uses non-aqueous electrolytic solution as electrolyte, and has an internal resistance of 5-10 Ω obtained from IR drop when capacitance is measured by a constant current discharge method of 30 mA/cm2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin, large-capacity capacitor having a large area applied to a backup power supply, a vehicle power supply, an auxiliary power supply, etc., which has a very large capacitance and a charge / discharge cycle. The present invention relates to an electric double-layer capacitor using solid carbon as a polarizable electrode and a non-aqueous electrolyte as an electrolyte, which is excellent in characteristics and rapid charging and is suitable for a power storage system for power having a large energy density.

[0002]

2. Description of the Related Art In recent years, charge accumulation based on electric double layers,
That is, an electrolyte is interposed between polarizable electrodes mainly composed of carbonaceous material, and an electric double layer formed at the interface between the two is used. Electric double layer capacitors having capacitance have been developed and commercialized.

Since such an electric double layer capacitor has both functions of a capacitor and a battery, it can be used not only as a small memory backup power supply but also as an initial drive of various motors and a large-capacity auxiliary power supply for a vehicle such as an electric vehicle. The demand is rapidly growing with the development of the electronics field, such as being applicable, maintenance-free, and having no risk of causing environmental pollution.

Conventionally, the electric double-layer capacitor is generally housed in a metal container together with an electrolytic solution via a separator between a pair of polarizable electrodes, or a large number of sheet-shaped capacitors for large current and large capacity. They have been constructed by laminating them with a separator interposed between polar electrode layers, storing in a container filled with an electrolytic solution, and sealing.

[0005] Initially, porous solid activated carbon, which is generally widely used, is used as the polarizable electrode material. Examples of such solid activated carbon include carbonaceous materials such as activated carbon, and tetrafluorocarbon. A sheet formed by kneading an organic resin such as a fluorinated ethylene resin or a fluorinated polymer and forming the sheet by a known molding means such as a roll molding method or a compression molding method has been used.

However, the capacitance of the electric double layer capacitor as described above is governed by the surface area of the polarizable electrode on which the electric double layer is formed, the capacitance per unit weight, the resistance of the electrode, and the like. In order to satisfy the performance of high capacitance and low internal resistance per unit weight of the electrode, and to satisfy the recent demand for miniaturization of electronic components, as a polarizable electrode, the volume of a given capacitance is minimized, In consideration of the impregnation property of the electrolyte and the electrolyte solution, solid activated carbon having a porous structure and having a large specific surface area without impairing durability and mechanical strength has been used as a polarizable electrode.

[0007] Therefore, as such solid activated carbon, activated carbon fine particles and carbon fibers are mixed and sintered under pressure, or a mixture of activated carbon powder and powdery phenol resin is injection-molded and heat-treated. Paper by adding pulp fiber, etc., press-bonding and baking a prepreg sheet mainly composed of activated carbon powder and cellulose fiber, or forming a mixture of activated carbon powder and phenolic resin on a substrate to form a non-oxidizing Heat-treating a mixture of a spherical carbide obtained by carbonizing a curable spherical phenolic resin and a heat-reactive spherical phenolic resin in an atmosphere, heat-treating the mixture in an inert atmosphere, and then performing activation treatment. Had been proposed.

However, the electrolyte used in the electric double-layer capacitor includes a non-aqueous electrolyte represented by an aqueous electrolyte and an organic electrolyte.
V, the latter is about 2.5 V, and the energy that can be stored by the electric double layer capacitor is proportional to the square of the withstand voltage. Therefore, the non-aqueous electrolyte stores about 8 times as much energy as the aqueous electrolyte. This is advantageous for miniaturization,
Although it has an excellent feature that a metal can be used for the exterior, the electric conductivity of a non-aqueous electrolyte is lower than that of an aqueous electrolyte, and therefore, generally, an electric double layer capacitor using such a non-aqueous electrolyte is However, there is a disadvantage that the internal resistance is increased.

Moreover, the solid activated carbon is generally amorphous carbon, does not have a highly oriented crystal structure like graphite, and has a large number of fine pores. When the polarizable electrode is composed of only such solid activated carbon, the resistance of the polarizable electrode increases, and as a result, the internal resistance of the electric double layer capacitor also increases.

Accordingly, in an electric double layer capacitor using a non-aqueous electrolyte as an electrolyte, for example, 3 mA / cm ²
When the capacitance is measured by the low current discharge method of about 20 F / g
When the capacitance is measured by a high current discharge method of about 30 mA / cm ^{2, the} energy that can be taken out by IR drop as an electric double layer capacitor because of the high internal resistance as described above. There is a problem that the density is reduced and the practicability is lacking.

In order to improve the conductivity of the polarizable electrode, reduce the internal resistance of an electric double layer capacitor using a non-aqueous electrolyte as an electrolyte, and reduce the IR drop, activated carbon is mainly used for the polarizable electrode. In addition to adding conductive materials such as carbon black and graphite as components, the specific surface area of carbon black and the specific surface area of It has been proposed to specify the ratio of carbon black in the total amount of activated carbon, carbon black and binder (see Japanese Patent Application Laid-Open No. 9-275041).

[0012]

However, the method of adding a highly conductive material such as carbon black or graphite to the polarizable electrode does not reduce the resistance of activated carbon itself as a main component. There is a limit in reducing the resistance of the polarizable electrode, and the internal resistance of the electric double layer capacitor cannot be sufficiently reduced to a practical range. For example, even if about 10 parts by weight of carbon black is added, the internal resistance is not reduced. 30
When an electric double layer capacitor is formed using a non-aqueous electrolyte as an electrolyte, the capacitance is as low as about 8 F / g at the time of high current discharge of about 30 mA / cm ² , and therefore, the energy density is low. There is a problem that the activated carbon used for the electric double layer capacitor is expensive, since it is a high-performance activated carbon.

[0013]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to reduce the internal resistance to 30 mA / cm.
^When obtained from the IR drop when the capacitance was measured by the constant current discharge method of No. 2, while reducing to 10Ω or less,
High output and high capacitance and high capacitance using a polarizable electrode made of solid carbon that has practical and high capacitance of F / g or more, high mechanical strength and excellent durability. An object of the present invention is to provide an electric double layer capacitor using a non-aqueous electrolyte having an energy density as an electrolyte.

[0014]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on the above-mentioned problems, and as a result, have developed a porous carbon exhibiting good conductivity with a large specific surface area within a range that does not impair durability or mechanical strength. A mixture comprising a main component made of a porous material, activated carbon and a carbonizable resin is molded, and the molded body is subjected to a carbonizing heat treatment in a non-oxidizing atmosphere, integrated, and then activated carbon is obtained. By using a polarizable electrode material, the above problem can be solved, and a practical capacitance can be obtained by reducing the internal resistance of the polarizable electrode, and it is made of solid carbon having excellent mechanical strength and durability. The present inventors have found that a high-output, high-energy-density electric double-layer capacitor using a non-aqueous electrolyte having a polarizable electrode as an electrolyte can be obtained, and the present invention has been accomplished.

That is, the electric double layer capacitor of the present invention comprises:
Its specific surface area is 700 m ² / g or more and 2000 m ² or more measured by a nitrogen adsorption method (BET method) comprising a carbonaceous material having good electrical conductivity of 0.5 Ω · cm or less and exhibiting good electrical conductivity as a main component and activated. ^A polarizable electrode composed of solid carbon of ² / g or less.
A / cm ² when measuring the capacitance by the constant current discharge method
The internal resistance obtained from the R drop is 0.5 to 10 Ω.

In particular, the specific surface area is 705 m ² / g
More preferably, it is in the range of 1400 m ² / g or less, and the internal resistance is 0.5 to 5.5Ω.

[0017]

In the electric double layer capacitor of the present invention, since the solid carbon mainly composed of a carbonaceous material exhibiting good electrical conductivity is used as the polarizable electrode material, the resistance of the carbonaceous material itself as the main component is reduced. Because of its low resistance, the polarizable electrode can also achieve low resistance, and after molding, it is subjected to carbonization heat treatment and further activated to form solid carbon with pores formed.
The carbonaceous material has a smaller specific surface area and a lower capacitance than activated carbon, so that the carbonaceous material has the same characteristics as the activated carbon.

As a result, when the carbonaceous material is used as a main component, solid carbon having large capacitance, high mechanical strength and excellent durability can be obtained. When the electrodes are configured, the resistance of the polarizable electrode is reduced, and the internal resistance of the electric double layer capacitor itself can be greatly reduced. As a result, a small and efficient electric double layer capacitor having excellent durability can be obtained. Can be

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The electric double layer capacitor of the present invention will be described below in detail. The electric double layer capacitor of the present invention, the polarizable electrode constituting the electric double layer capacitor,
A main component carbonaceous conductive material having a 0.5 .OMEGA · cm or less conductivity, activation treatment and the specific surface area measured by nitrogen adsorption method (BET method) is 700 meters ² / g or more, 2000 m ² /
g of solid carbon having a capacity of 0 g or less is used as a polarizable electrode, and the internal resistance obtained from the IR drop when the capacitance is measured by a constant current discharge method of 30 mA / cm ² using an electrolyte composed of a non-aqueous electrolyte is 0. More preferably, the specific surface area is in the range of 705 m ² / g to 1400 m ² / g, and the internal resistance is in the range of 0.5 to 5.5 Ω.

In the present invention, the carbonaceous conductive material comprises:
Incomplete combustion of gaseous or liquid hydrocarbons, or carbon with a crystallinity of about 0.4 to 3.0 obtained by pyrolysis at about 1300 ° C. It has a particle diameter of about, it forms a particle aggregate of about thousands to tens of thousands of nanometers that are aggregated, for example, those exhibiting the conductivity described below, such as acetylene black and Ketjen black Any of these may be used, but Ketjen Black is most desirable in terms of the specific surface area as described in detail below.

Note that the crystallinity is an expression expressed by 2d × sin θ = nλ in the X-ray diffraction method, where d is the ratio of the half-width of the strongest peak near 38 nm to the height of the peak from the base. This is the calculated value.

That is, when the specific surface area of the solid carbon containing the carbonaceous conductive material as a main component is less than 700 m ² / g as measured by a nitrogen adsorption method (BET method), the solid carbon and the electrolyte are mixed. Since the number of electric double layers formed at the interface decreases, the capacitance becomes lower than 5 F / g, which is not practical. On the other hand, when the specific surface area exceeds 2000 m ² / g, the density and solid carbon The strength is reduced, and handling properties and durability are deteriorated.

Therefore, the specific surface area and conductivity of the carbonaceous conductive material as the main component may be selected depending on the desired internal resistance and capacitance, and the specific surface area of the solid carbon is determined by the carbonaceous conductive material. Although the upper limit is limited by the specific surface area, in an electric double layer capacitor using a solid carbon mainly composed of the carbonaceous conductive material as a polarizable electrode, the specific surface area is 700 m ² / g or more and 2000 m ² or more.
/ G or less, and in particular, has a capacitance as an electric double-layer capacitor and a strength that does not cause breakage such as chipping or cracking during a manufacturing process or during incorporation as a polarizable electrode of the electric double-layer capacitor. In view of this, the specific surface area of the solid carbon is 705 m ² / g or more and 1400
m ² / g or less is most desirable.

Further, the conductivity of the carbonaceous conductive material is 0.5
When the resistance exceeds Ω · cm, when an electric double layer capacitor is formed using solid carbon made of the material as a polarizable electrode, the internal resistance becomes as high as 20 Ω or more and does not contribute to the reduction of the internal resistance. cm or less.

In particular, from the viewpoint of the effect of reducing the internal resistance and the capacitance ratio of the capacitance at the time of low current discharge to the capacitance at the time of high current discharge, the conductivity of the carbonaceous conductive material is 0.1%.
More preferably, it is 3 Ω · cm or less.

Next, the solid carbon of the present invention contains the above-mentioned carbonaceous conductive material as a main component, and may further contain activated carbon. Comprising, further subjected to activation treatment, the content of the carbonaceous conductive material, without lowering the capacitance of the electric double layer capacitor,
55% by weight in terms of effectively reducing the internal resistance
The above is necessary, and from the viewpoint of improving the capacitance, 70 to 90% by weight is most desirable.

The activation treatment is generally a gas activation which is a physical activation for forming fine pores by contacting a carbide with steam, carbon dioxide, oxygen, or other oxidizing gas at a high temperature. In addition, in the present invention, oxygen activation treatment is the most preferable treatment method in consideration of production cost, environmental safety, simplicity of treatment method, and the like.

The carbonizable resin to be added as the binder may be any known organic resin, and is not particularly limited. Examples thereof include phenol or Teflon, coal tar, and polyvinyl butyral (PVB). And polyvinyl acetate such as polyvinyl formal (PVFM) and vinyl acetate. Particularly, polyvinyl butyral (PVB) is most desirable from the viewpoint of moldability or the strength of the obtained solid carbon.

The activated carbon is not particularly limited, and may be any of coconut shells, phenols, petroleum coke, etc., and from the viewpoint of cost and adsorption capacity, coconut shells may be used as the electric double layer. From the viewpoint of increasing the capacity of the capacitor and reducing the internal resistance, a phenol-based or petroleum coke-based is preferred.

Next, the internal resistance of the electric double layer capacitor using the solid carbon as a polarizable electrode in the present invention is obtained from the IR drop shown in FIG. 1, that is, the initial voltage drop. After charging at a voltage of 0.5 V and discharging at a constant current of 30 mA / cm ² , a point on the discharge curve after a discharge time of 5 seconds and a voltage of 0 V
The points of the discharge curve at the time of are connected by a straight line, and the voltage E when the discharge time is 0 seconds obtained by extending the straight line and the discharge current I of 30 mA
Is used to calculate the internal resistance R from the relational expression of R = E / I.

Therefore, the capacitance at this time becomes lower as the IR drop becomes larger, and the IR drop becomes larger as the discharge current density becomes higher. Should be lowered,
In addition, the effect of the capacitance on the internal resistance tends to be greater as the current is discharged at a higher current.

In the present invention, the value of the internal resistance is a solid carbon having an internal resistance of less than 0.5 Ω when the capacitance is measured by a constant current discharge method of 30 mA / cm ² as an electric double layer capacitor. When a polarizable electrode is used, the production cost of the solid carbon is extremely high, there is a drawback that the solid carbon is not practical and the moldability is poor. Due to the characteristics of the material or activated carbon, the capacitance of an electric double layer capacitor is low, the capacitance ratio of the capacitance at low current discharge to the capacitance at high current discharge is small, or the energy density is low. There is a problem that it is not practical due to any of the following factors: low, insufficient mechanical strength, poor moldability, and the like.

Accordingly, the internal resistance of the electric double layer capacitor using the solid carbon as a polarizable electrode has a problem in practical use because the electric double layer capacitor has a practical capacitance of 25 F / g or more. 0.5-1 in that it does not occur
It must be in the range of 0Ω.

Further, considering the capacity ratio of the capacitance at the time of low current discharge to the capacitance at the time of high current discharge in terms of expanding the application range, the value of the internal resistance is 0.5 to 0.5.
It is within the range of 5.5Ω, and has a strength that does not cause breakage such as chipping or cracking during the manufacturing process or when incorporated as a polarizable electrode of an electric double layer capacitor as described above. The specific surface area of carbon is 705 m ² /
Most preferably, it is not less than g and not more than 1400 m ² / g.

Next, an example of the method for producing solid carbon of the present invention will be described. First, phenol resin-based, coconut shell-based, petroleum coke-based or other known activated carbon is mixed in an amount of less than 100 parts by weight with respect to 100 parts by weight of a carbonaceous material such as carbon black having a conductivity of 0.5 Ω · cm or less. Further, in order to improve the strength and moldability of the solid carbon, at least one of known carbonizable resins such as phenol or Teflon, coal tar, and polyvinyl butyral (PVB) is mixed, and the mixture is mixed with slurry or granulated. The body is prepared to prepare the molding material.

Thereafter, using the obtained molding material, a known molding method such as a doctor blade method, a tape molding method, a pressure molding method, a roll molding method, an extrusion molding method, or a molding method combining them is used. It is molded into a predetermined shape, and the obtained molded body is carbonized and heat-treated to carbonize the carbonizable resin in the molded body, and the carbonaceous material such as the carbon black and the carbide of the carbonizable resin are calcined and integrated. By performing the activation treatment, pores are formed to obtain solid carbon.

The carbonizing heat treatment temperature is set to 600 ° C. in a non-oxidizing atmosphere in order to sufficiently promote the carbonization of the carbonizable resin and promote the sintering of the neck portion of the carbon black to maintain sufficient strength. A temperature of about 1200 ° C. to 1200 ° C. is desirable, and a temperature of 700 ° C. to 900 ° C. is particularly optimal.

The activation treatment is preferably carried out at a temperature of about 300 to 600 ° C. in the air, especially 4 ° C. in order to regenerate the pores reduced by the carbonizing heat treatment by an oxidation reaction.
A temperature between 00 and 500 ° C. is optimal.

Therefore, if the carbonization heat treatment temperature is increased or the carbonization time is lengthened, the strength is improved, but the specific surface area is reduced.

On the other hand, in the activation treatment, if the temperature is increased or the activation time is lengthened, the strength is reduced, but the pores are reformed and the specific surface area is increased. It is important to select carbonization heat treatment conditions and activation heat treatment conditions so as to have an optimum pore distribution in consideration of the capacity.

The solid carbon of the present invention may be formed into a sheet shape by a doctor blade method, a calendar roll method, or the like to form a carbon substrate, formed into a block shape by various press molding methods, or extruded. Various shapes can be obtained by forming a rod shape or a cylindrical shape, or by combining them.

Further, after laminating a plurality of the sheet-like molded bodies, it is also possible to perform a heat treatment in a non-oxidizing atmosphere. By bonding with an adhesive or the like, it is also possible to offset the directions of warpage and reduce the occurrence of warpage during heat treatment.

[0043]

EXAMPLES The electric double layer capacitor of the present invention was evaluated as follows. First, a carbon black having a conductivity and a specific surface area (BET value) shown in Table 1 was used as a carbonaceous conductive material, and the carbon black and the specific surface area (BET value) were used.
Value) is 1780 m ² / g, and the raw material is a mixture of activated carbon obtained by alkali-activating tar obtained from coal.
In parts by weight, the carbon black is 40, 55, 70,
80, 90, 100 parts by weight blended,
Furthermore, PVB is adjusted according to the BET value of the carbon black.
Were mixed with a high-speed mixing stirrer, and the obtained granules were sieved with a 42-mesh sieve to prepare a raw material for molding.

Next, the obtained molding material is press-molded,
Alternatively, after a roll-formed body is obtained to obtain a plate-shaped body, the body is subjected to a heat treatment for 48 hours at 200 ° C. under aging conditions in the air, and then 800 ° C. in vacuum.
The carbonization heat treatment was performed under the processing conditions of maintaining the temperature at a temperature of ° C for 60 minutes.

In the above-mentioned molding, the moldability was evaluated based on the presence or absence of cracks, chips, and the like of the molded body including the possibility of molding.

Thereafter, the carbonized heat-treated sample was placed in air.
The activation treatment is performed by holding at a temperature of 450 ° C. for 180 minutes,
PVB is carbonized to form a composite of carbon black and activated carbon, or carbon black, 90 mm long and 6 mm wide.
A solid carbon plate for evaluation having a thickness of 0 mm and a thickness of 1 mm was prepared.

The specific surface area of each of the thus obtained solid carbon plates for evaluation was measured by a nitrogen adsorption method (BET method).

Next, each of the solid carbon plates for evaluation was used as a polarizable electrode, and an electrolytic solution in which lithium perchlorate was dissolved so as to have a concentration of 1 mol in 1 liter of a propylene carbonate solution was used. 30 at a voltage of .5V
After charging for a minute, the capacitance per unit weight of the electrode (F / g) was determined by a constant current discharge method of 30 mA / cm ² , and the internal resistance was determined from the IR drop at that time as described in detail above.

The evaluation of the mechanical strength was carried out by cutting a length 40 mm and a width 4 m cut out from the solid carbon plate for evaluation.
m, 1 mm thick test piece, distance between fulcrums 30 mm
And a crosshead speed of 0.5 mm / min. A three-point bending test was performed under the conditions described above, and calculated from the breaking load.

On the other hand, the energy density was calculated from the electrostatic capacity per unit weight obtained by the constant current discharge method of 30 mA / cm ^{2 and} the charged voltage determined from the specific decomposition voltage of the electrolytic solution.

Further, a phenol-based activated carbon having a specific surface area of 1950 m ² / g and an average particle size of 10 μm, which was activated with molten potassium hydroxide (KOH), was 70% by weight, and a Ketjen having a specific surface area of 1270 m ² / g. Black EC-60
0 JD 20% by weight, polytetrafluoroethylene 10
Ethanol was added to the mixture consisting of wt.% And kneaded. After roll forming, the formed body was dried at a temperature of 200 ° C. for 2 hours to produce a solid carbon plate having the same dimensions and shape as the solid carbon plate for evaluation. An electric double layer capacitor similarly formed as a polarizable electrode was used as a comparative example.

[0052]

[Table 1]

[0053]

[Table 2]

As is clear from Tables 1 and 2, Sample No. 30 of the comparative example has an internal resistance of 30.0 Ω, and the capacitance of the capacitance at the time of low current discharge is smaller than the capacitance at the time of high current discharge. The ratio is as low as 32.0% and the energy density is 7.0w
h / kg, which is extremely low and has an internal resistance of 11.0Ω or more, which is out of the scope of the present invention.
In 3, 19 and 25, the energy density is 21 wh / kg
Sample No. 28 in which the BET value of the solid carbon is out of the range of the present invention is low, the mechanical strength is low, the handling property is poor, the moldability is insufficient, and the BET value is low. Sample No. 26, which is less than 700 m ² / g, has a very low capacitance and does not show a capacitance during high-current discharge, and therefore has an energy density of 0, while Sample No. 29 having an internal resistance of less than 0.5Ω. Is not practical because of poor moldability.

On the other hand, in the present invention, all
The internal resistance of the electric double layer capacitor for evaluation obtained from the R drop is as low as 10Ω or less, and the capacitance is also 3 mA / cm.
33F / g or more discharge at ^2, and shows a higher 25F / g at a discharge at 30 mA / cm ^2, volume ratio is also 73.5%
As well as satisfying the above, the mechanical strength is also 433 gf / mm.
² or more, the energy density was 22 wh / kg or more, and it was confirmed that there was no problem in moldability.

It should be noted that the present invention is not limited to the above-described embodiment, but it is needless to say that the present invention can be achieved as long as it satisfies the gist of the present invention.

[0057]

As described in detail above, the electric double layer capacitor of the present invention is mainly composed of a carbonaceous conductive material having a conductivity of 0.5 Ω · cm or less, and has a specific surface area determined by a nitrogen adsorption method (BET method). When the polarizable electrode is composed of solid carbon having a value of 700 m ² / g or more and 2000 m ² / g or less, and the capacitance is measured by a constant current discharge method of 30 mA / cm ² using a non-aqueous electrolyte as an electrolyte. Since the internal resistance obtained from the IR drop is 0.5 to 10Ω, the internal resistance of the electric double layer capacitor using a non-aqueous electrolyte as the electrolyte can be effectively reduced, and at the time of high current discharge and low current discharge. The capacitance at the time can be greatly improved, and with a simple structure having practical capacitance, high output, high energy density, high efficiency, and high mechanical strength,
A small electric double layer capacitor having a polarizable electrode having excellent durability can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a correlation between a voltage and a discharge time for explaining a procedure for measuring an internal resistance of an electric double layer capacitor of the present invention.

Claims (2)

[Claims] 1. A specific surface area of 700 m ² / g or more and 2000 m ² / g or less as determined by a nitrogen adsorption method (BET method) containing a carbonaceous conductive material having a conductivity of 0.5 Ω · cm or less as a main component. The internal resistance obtained from the IR drop when the capacitance was measured by a constant current discharge method of 30 mA / cm ² using an electrolyte composed of a non-aqueous electrolyte as a polarizable electrode using solid carbon was 0.5 to 10 Ω. An electric double layer capacitor characterized by the following. 2. The method according to claim 1, wherein the specific surface area is 705 m ² / g or more,
00 m ² / g or less, and the internal resistance is 0.5-5.
The electric double layer capacitor according to claim 1, wherein the electric double layer capacitor is 5Ω.