JP2001332456A - Electric double-layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an electric double-layer capacitor(EDLC) which allows a high output power to be extracted, without lowering the internal resistance, and attains a high-energy density structure. SOLUTION: The electric double-layer capacitor, composed of a positive and negative electrodes at least either of which is a polarizable electrode containing active carbon and carbon black, a separator inserted between the positive and negative electrodes and an aqueous electrolyte has carbon black which uses a carbon black baked in air without oxygen or vacuum or an inert atmosphere at 1,800-3,000 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric double layer capacitor capable of increasing the energy density, and in particular, has a long charge / discharge cycle life, is capable of large current charge / discharge, a backup power supply for various electronic devices, and a hybrid car. The present invention relates to an electric double layer capacitor suitable for an electric vehicle and the like.

[0002]

2. Description of the Related Art
Electric Double Layer Capacitor (Electrical Dou)
ble-layer Capacitor;
DLC. " )) Is a device in which a separator is sandwiched between a pair of polarizable electrode layers in which a polarizable electrode layer containing activated carbon as a main component is provided on a current collector. Sealed in a metal container with a case and its sealing member (or lid) and a gasket that insulates between the case and the sealing member, or a laminate in which a separator is sandwiched between polarizable electrode layers of a pair of sheet-shaped polarizable electrodes There has been proposed a device in which a sheet is wound to form an element, which is housed in a metal container together with an electrolytic solution, and sealed with a sealing member so that the electrolytic solution does not evaporate from an opening of the metal container.

[0003] In addition, various types of stacked EDLCs having an element in which a separator is sandwiched between polarizable electrode layers of a large number of sheet-shaped polarizable electrodes for a large current and a large capacity have been proposed (Japanese Patent Laid-Open No. Hei. No. 154106, Japanese Unexamined Patent Publication No.
No. 203331, JP-A-4-286108, etc.).

In these EDLCs, for example, a sheet-shaped polarizable electrode formed into a rectangular shape is laminated to a positive electrode and a negative electrode current collector by sandwiching a separator between the positive electrode and the negative electrode current collector. A stacked element formed by connecting a positive electrode lead member and a negative electrode lead member to the end of the container is housed in a container, an electrolytic solution is injected into the container, and the container is sealed with a sealing member.

In the EDLC, the polarizable electrode is mainly composed of activated carbon having a large specific surface area, and the electrolyte is a high dielectric constant such as water and carbonates for dissolving the electrolyte at a high concentration. Of solvents are used.

In this case, activated carbon having a large specific surface area, which is a main component of the polarizable electrode, generally has low electric conductivity, and it is difficult to take out a large current by using the activated carbon alone because the internal resistance of the polarizable electrode becomes large. is there. Therefore, a conductive material such as carbon black is added to the polarizable electrode for the purpose of imparting conductivity and lowering the internal resistance.

However, when the proportion of the conductive material in the polarizable electrode is increased, the internal resistance can be reduced. On the other hand, the proportion of the activated carbon decreases, so that the capacitance of the EDLC decreases. This means that the upper limit of the specific surface area of the activated carbon is about 3,000 m ² / g, and the capacitance per unit volume of the EDLC using the activated carbon has almost reached the limit. There is a strong demand for the development of a new measure for lowering the internal resistance without reducing the internal resistance, and for providing an electric double layer capacitor capable of further increasing the energy density.

The present invention has been made in view of the above circumstances, and it is possible to reduce the internal resistance without lowering the capacitance of a polarizable electrode, and to realize a high-quality electricity capable of achieving a high energy density. It is an object to provide a double layer capacitor.

[0009]

Means for Solving the Problems and Embodiments of the Invention As a result of intensive studies to achieve the above object, the present inventor has found that at least one of the positive electrode and the negative electrode contains activated carbon and carbon black. And a separator interposed between the positive and negative electrodes, and a non-aqueous electrolyte solution. The carbon black of the polarizable electrode is formed at 1800 to 3000 ° C. under oxygen-blocking air or vacuum or an inert atmosphere. By using the calcined calcined carbon black, the calcined carbon black undergoes crystal growth in the particles while substantially maintaining the original particle diameter of the carbon black, and eventually changes from a sphere to a polyhedron and becomes graphite. Has a structure very similar to that of activated carbon, has a large apparent specific gravity, reduces volume loss, and reduces the amount of activated carbon added. The present invention has been found to be able to provide excellent electrical conductivity, reduce internal resistance, and to obtain a high-quality electric double layer capacitor having an extremely high energy density as compared with the related art. Reached.

Accordingly, the present invention provides the following electric double layer capacitor. Claim 1: At least one of a positive electrode and a negative electrode is formed of a polarizable electrode containing activated carbon and carbon black, and an electric double layer composed of a separator interposed between the positive and negative electrodes and a non-aqueous electrolyte. A capacitor, wherein the carbon black is 1800 to 3000 ° C. under oxygen-blocking air or vacuum or an inert atmosphere;
An electric double layer capacitor characterized by using a fired carbon black fired in the above. In another preferred embodiment, a polarizable electrode containing activated carbon and a binder and activated carbon and fired carbon black fired at 1800 to 3000 ° C. under vacuum or inert atmosphere at 180 to 3000 ° C. is used as a positive electrode, and lithium ions are reversibly occluded as a negative electrode. 2. The electric double layer capacitor according to claim 1, wherein a non-polarizable electrode including a carbon material in which lithium ions are occluded in a releasable carbon material is used.

Hereinafter, the present invention will be described in more detail. The electric double layer capacitor (EDLC) according to the present invention is configured such that at least one of the positive electrode and the negative electrode is formed of a polarizable electrode containing activated carbon, carbon black, and a binder. An electrolyte solution, wherein the carbon black is 1% in oxygen-blocked air or in a vacuum or inert atmosphere.
It uses fired carbon black fired at 800 to 3000 ° C.

As the activated carbon constituting the polarizable electrode of the present invention, phenol resin-based activated carbon, coconut-based activated carbon, petroleum coke-based activated carbon and the like can be used. Among them, a large-capacity EDLC can be obtained. Thus, petroleum coke-based activated carbon and phenol resin-based activated carbon are particularly preferred.

In this case, the activated carbon has an average particle size of 20 μm or less, preferably 5 to 20 μm, and a specific surface area of 1500 to 3000 m ² / g for the purpose of increasing the capacitance and reducing the internal resistance. It is preferable to use activated carbon powder which is

As the activated carbon activation method, there are a steam activation method, a solvent KOH activation method and the like. However, since a larger volume of EDLC can be obtained, it is necessary to use activated carbon by the solvent KOH activation method. preferable.

The added amount of the activated carbon is 65 to 9 with respect to the total amount of the activated carbon, the calcined carbon black and the binder.
It is 8% by weight, preferably 70-98% by weight. If the amount is too small, the capacitance required by the EDLC may not be obtained. On the other hand, if the amount is too large, there is less room for other components to enter, which may cause a problem in binding properties and conductivity.

The carbon black of the present invention is added for the purpose of imparting conductivity to the polarizable electrode to reduce its internal resistance, and is produced as follows.

First, according to the conventional furnace black production method, the primary particle diameter is 20 to 55 nm, and the specific surface area determined by the BET method is 500 m ² / g or more, preferably 5 m ² / g or more.
A highly conductive carbon black of 50 to 1800 m ² / g is obtained. This carbon black can be used in an oxygen-barrier air or vacuum or inert atmosphere at 1800 to 3000
It is preferable to carry out pulverization or preliminary firing as a pretreatment for main firing at a temperature of ° C.

In this case, the preliminary firing is performed in an atmosphere of an inert gas such as nitrogen, argon, helium, etc., particularly in a nitrogen gas atmosphere at a temperature of 900 to 1200 ° C., preferably 950 ° C.
It is to be fired in a range of 1 to 1100 ° C for 1 to 24 hours. By this preliminary baking, organic substances as impurities, water, and surface functional groups of carbon black can be removed.
In other words, there are various types of functional groups that are responsible for chemical reactions on the surface of carbon black, and removing these surface functional groups is effective not only in protecting the equipment in the main firing but also in obtaining high conductivity. It is something.

Specifically, the physically adsorbed moisture on the carbon black surface can be removed as steam gas at 100 ° C. Carboxyl groups can be removed as carbon dioxide gas at 200-300 ° C. 400 ° C for hydroxyl group
Can be removed as steam gas. The carbonyl group, acyl group, methylene chain, and ether chain are 600 to
At 900 ° C., it can be removed as carbon monoxide gas or hydrogen.

Next, the prefired carbon black is subjected to main firing at a temperature of 1800 to 3000 ° C. under oxygen-blocking air, vacuum or an inert atmosphere. In this case, the main firing is performed under oxygen-blocked air, vacuum, or an inert atmosphere, but the temperature may be changed from vacuum to an inert atmosphere during the temperature raising process. As the inert atmosphere, a rare gas such as helium, neon, or argon is used, and argon is particularly preferable. Alternatively, a method in which prefired carbon black is put into a carbon crucible, and a large amount of sacrificial carbon is disposed around for the purpose of blocking oxygen in the air, and firing is performed while blocking oxygen in the surrounding air.

The temperature at the time of the main firing is 1800-3000 ° C.
, Preferably 2200 to 2900 ° C. Generally, when carbon black is treated at a high temperature of 2000 to 3000 ° C., crystal growth occurs in the particles while substantially maintaining the original particle diameter, and finally carbon black having a large apparent specific gravity changed from a sphere to a polyhedron is obtained. On this occasion,
The firing time is preferably 1 to 40 hours because the pore volume may be significantly reduced.

The carbon black of the present invention thus obtained is obtained by using unfired carbon black or 18 carbon black.
The graphitized structure is more developed than carbon black fired at less than 00 ° C. As an index indicating the degree of development of the graphitized structure, an average plane spacing (d002) described on pages 24 to 26 of "Introduction to New Carbon Materials" edited by the Society of Carbon Materials, Japan can be used. In this case, the average interplanar spacing (d002) of graphite is 0.3354 nm, and it can be said that the closer to this value, the more the graphitized structure is developed.

The calcined carbon black of the present invention has an average plane distance (d002) of 0.3354 nm or more and 0.34 nm or more.
It is preferably in the range of 5 nm or less, and the structure is very similar to graphite. Further, the pore volume of the carbon black is preferably 0.2 mL / g or more,
More preferably, it is 0.3 mL / g or more.

The amount of the calcined carbon black is 1 to 35% by weight, more preferably 2 to 30% by weight, based on the total amount of the activated carbon, the calcined carbon black and the binder.
It is. If the added amount of the calcined carbon black is too small, the conductivity becomes insufficient, so that the internal resistance may become too large to take out a large current. On the other hand, if it is too large, the amount of activated carbon as a main material decreases, and thus the capacitance may decrease.

Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride, carboxymethyl cellulose, and the like. One of these binders can be used alone, or two or more can be used in combination. Among them, polytetrafluoroethylene (PT
FE) is preferred.

The amount of the binder to be added is 0.1 to the total amount of activated carbon, calcined carbon black and the binder.
The content is 5 to 20% by weight, more preferably 0.5 to 10% by weight. If the amount is too small, the strength of the electrode may decrease.
On the other hand, if the amount is too large, the amount of the activated carbon, which is the main material, decreases, so that the capacitance of the polarizable electrode may decrease.

The polarizable electrode of the present invention can be manufactured by a known method. For example, a mixture of activated carbon powder, calcined carbon black and a binder, if necessary, a solvent such as alcohol is added and kneaded, and molded into a sheet or the like to obtain a polarizable electrode. It is obtained by bonding to a current collector with a conductive adhesive or the like. As the current collector, stainless steel, aluminum, titanium, tantalum, nickel, or the like can be used. Among these, stainless steel and aluminum are preferred from both the viewpoint of performance and cost. The current collector may have various forms such as a three-dimensional structure such as a foil shape, an expanded metal shape, a plate shape, a foamed shape, a wool shape, and a net shape.

Further, a solvent is mixed with activated carbon powder, calcined carbon black and a binder to form a slurry. This slurry is coated on a metal foil current collector such as aluminum, crosslinked and dried to be integrated with the current collector. It can also be manufactured by a method of obtaining a polarized polarizable electrode.

In this case, the solvent of the slurry is N-
Methylpyrrolidone, dimethylformamide, toluene,
Xylene, isophorone, methyl ethyl ketone, ethyl acetate, methyl acetate, dimethyl phthalate, ethanol, butanol, water and the like. As the crosslinking agent for the binder, for example, amines, polyamines, polyisocyanates, bisphenols, peroxides and the like are suitable.

In the present invention, an EDLC can be assembled by using the polarizable electrode thus obtained for at least one of the positive electrode and the negative electrode, preferably both. However, the present invention is not limited thereto. A non-polarizable electrode containing a battery active material such as a metal oxide as a main component is used as a positive electrode, the polarizable electrode of the present invention is used as a negative electrode, and lithium is used as a negative electrode for a carbon material capable of reversibly occluding and releasing lithium ions. It is possible to use a non-polarizable electrode containing a carbon material having occluded ions as a main component and the polarizable electrode of the present invention as a positive electrode.

Above all, a non-polarizable electrode containing a carbon material in which lithium ions were inserted into a carbon material capable of reversibly occluding and releasing lithium ions was used as a negative electrode, and the polarizable electrode of the present invention was assembled as a positive electrode. EDLC is excellent in charge / discharge cycle durability and safety, can increase the operating voltage, has a large capacitance, and is a preferred EDLC.

The non-polarizable electrode constituting the negative electrode contains a carbon material capable of occluding and releasing lithium ions reversibly and a binder as main components. Examples of carbon materials capable of reversibly occluding and releasing lithium ions include natural graphite, artificial graphite, graphitized mesocarbon small spheres, graphitized whiskers, vapor-grown carbon fiber, fired products of furfuryl alcohol resin, and novolak resin. And the like, and one of these can be used alone or in combination of two or more.

Examples of the binder to be mixed with the non-polarizable electrode include polytetrafluoroethylene, polyvinylidene fluoride, a crosslinked polymer of a fluoroolefin / vinyl ether copolymer, carboxymethylcellulose, polyvinylpyrrolidone, polyvinyl alcohol, and polyacrylic acid. These can be used alone or in combination of two or more.

The amount of the binder is preferably 0.5 to 20% by weight based on the total amount of the carbon material and the binder. If the amount of the binder is too small, the strength of the electrode may be insufficient. On the other hand, if the amount is too large, the electric resistance may increase or the capacitance may decrease. In consideration of the balance between the capacitance and the strength of the electrode, the blending amount of the binder is particularly preferably 0.5 to 10% by weight.

The method for producing a non-polarizable electrode containing a carbon material in which lithium ions are occluded in the carbon material capable of storing and releasing lithium ions is basically the same as that of the polarizable electrode of the present invention. A solvent such as alcohol is added to a powder of a carbon material capable of occluding and releasing lithium ions and a binder, and the mixture is kneaded and formed into a sheet to form a sheet electrode, and the sheet electrode is collected with a conductive adhesive or the like. It can be manufactured by bonding to a body.

Further, a solvent is mixed with a powder of a carbon material capable of occluding and releasing lithium ions and a binder to form a slurry, which is coated on a metal foil of a current collector, crosslinked, and dried to form a slurry. An integrated non-polarizable electrode can also be manufactured. As the slurry solvent and the cross-linking agent, the same one as the above-mentioned polarizable electrode can be used.

Next, the carbon material capable of reversibly occluding and releasing lithium ions is made to occlude lithium ions by a chemical method or an electrochemical method. As the chemical method, for example, a method in which powdery lithium is mixed with a carbon material capable of absorbing lithium ions to form a sheet-like electrode, and a sheet-like electrode formed of a carbon material capable of absorbing lithium ions and a binder A method in which foil-like lithium is placed on an electrode, and the electrode is immersed in, for example, the same non-aqueous electrolyte solution that is injected into the EDLC, thereby incorporating lithium ions into a carbon material capable of storing lithium ions. There is. On the other hand, as an electrochemical method, for example, an electrode formed of a carbon material capable of occluding lithium ions and a binder and an electrode of lithium metal are immersed in an organic electrolytic solution using a lithium salt as an electrolyte, and current is applied between the two. And taking lithium into the carbon material in an ionized state.

The non-polarizable electrode thus obtained is
The shape may be any of a film shape, a sheet shape, and a plate shape. The current collector that can be combined with the non-polarizable electrode may be any conductive material that is electrochemically and chemically resistant. For example, stainless steel, copper, nickel, and the like are preferable.

The EDLC of the present invention is housed in an EDLC container with a separator interposed between a pair of polarizable electrodes obtained as described above or between a polarizable electrode and a non-polarizable electrode. It is assembled by injecting a liquid and sealing with a sealing member.

In this case, the shape of the EDLC is preferably a coin shape or a film shape, but is not limited thereto. The EDLC is formed by winding a pair of long electrode bodies through a long separator. Is formed, and the element is impregnated with a non-aqueous electrolytic solution and is housed in a bottomed cylindrical case, and a plurality of electrode bodies are alternately stacked as a positive electrode body and a negative electrode body via a separator. A device having various shapes such as a square shape formed by impregnating the device with a non-aqueous electrolytic solution and housing the device in a bottomed square case can be used.

As the above-mentioned separator, the one usually used as a separator for EDLC can be used. For example, polyethylene non-woven fabric, polypropylene non-woven fabric, polyester non-woven fabric, PTFE porous film, kraft paper, rayon fiber / sisal fiber mixed sheet, manila hemp sheet, glass fiber sheet, cellulosic electrolytic paper, paper making of rayon fiber, cellulose and glass fiber Mixed paper, or a combination of these into a plurality of layers can be used.

As the electrolyte of the EDLC of the present invention, a known non-aqueous electrolyte can be used. Examples of the electrolyte of the nonaqueous electrolyte include tetraalkylphosphonium tetrafluoroborate, tetraalkylammonium tetrafluoroborate, tetraalkylphosphonium hexafluorophosphate, tetraalkylammonium hexafluorophosphate, and the like; lithium salt electrolytes include LiClO ₄ , LiCF ₃ SO ₃ , Li
BF ₄ , LiPF ₆ , LiAsF ₆ , LiCF ₃ CO ₂ , L
iN (CF ₃ SO ₂ ) and the like, and one of these can be used alone or in combination of two or more.
Among them, tetraethylammonium tetrafluoroborate, triethylmonomethylammonium tetrafluoroborate, tetraethylphosphonium tetrafluoroborate, LiClO ₄ and LiPF ₆ are preferable.

Examples of the solvent of the non-aqueous electrolytic solution that can dissolve the above-mentioned electrolyte include propylene carbonate (PC), γ-butyrolactone (B
L), dimethylformamide (DMF), dimethylsulfoxide (DMSO), acetonitrile (AN), ethylene carbonate (EC), tetrahydrafuran (TH
F), dimethoxyethane (DME), methyl formate (MF), and the like. One of these can be used alone, or a mixed solvent of two or more can be used. The concentration of the electrolyte in the electrolyte is about 0.5 to 1.0 mol / L.

The EDLC of the present invention uses a pair of polarizable electrodes of the present invention containing a calcined carbon black having a reduced graphite structure and a small volume loss as a conductive material, or preferably, reversibly converts the polarizable electrodes and lithium ions. Occlusion,
By using in combination with a non-polarizable electrode containing a carbon material in which lithium ions are occluded in a carbon material that can be released, the internal resistance can be reduced without lowering the capacitance of the polarizable electrode, It is possible to take out high output, and it is used as a memory backup power supply for personal computers and portable terminals, etc. It can be suitably used for various applications such as a system and a load leveling power supply combined with a battery.

[0045]

According to the present invention, the internal resistance can be reduced without lowering the capacitance of the polarizable electrode, a high energy density can be achieved, rapid charge / discharge is possible, and charge / discharge is possible. And a high quality electric double layer capacitor (EDLC) that can be charged and discharged with a large current and has a long cycle life.

[0046]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In this embodiment, a coin-type EDLC using a polarizable electrode for both the positive electrode and the negative electrode is used. However, a non-polarizable electrode may be used as one of the positive electrode and the negative electrode.

Production of Carbon Black ²⁰ g of carbon black having a primary particle size of 33.9 nm and a specific surface area of 1340 m ² / g determined by the BET method (Carbon ECP600JD, manufactured by Ketchen Black International Co., Ltd.) was placed in an alumina crucible. Pre-firing under a nitrogen stream at 1000 ° C. for 5 hours.

Next, 12 g of the prefired carbon black, once cooled to room temperature, was placed in a carbon crucible with a screw cut in a lid, and was fired in an electric furnace capable of raising the temperature to 3000 ° C. Specifically, at room temperature (20
° C) to 2000 ° C for 80 minutes by evacuation. The temperature was raised from 2000 ° C. to 2800 ° C. in an argon stream over 50 minutes. The firing was performed for 5 hours under a stream of argon at 2800 ° C., and then cooled to room temperature. The obtained calcined carbon black was designated as CB1. The average plane distance d (002) of CB1 was 0.342 nm. The average plane distance d (002) is a value based on the description on pages 24 to 26 of “Introduction to New Carbon Materials” edited by the Society of Carbon Materials, Japan. Average plane spacing (d002) of graphite is 0.3354 nm
The closer the value is, the more the graphitized structure is developed.

As in the case of CB1, 100 g of prefired carbon black is placed in a carbon crucible, and a large amount of sacrificial carbon is placed around it for the purpose of blocking oxygen in the air. Warmed. Subsequently, after baking at the same temperature for 24 hours, it was cooled to room temperature. The carbon black thus obtained was designated as CB2. The average surface distance d (002) of CB2 is 0.33
It was 8 nm.

For comparison, carbon black (CBa) before calcination of CB1 and acetylene black, Denka Black (CBb) manufactured by Denki Kagaku Kogyo KK, CB1
Carbon black (CBc) was prepared by simply pre-baking a at 1000 ° C. Table 1 shows the values of the average interplanar spacing d (002) of the carbon black together with CB1 and CB2.

[0051]

[Table 1]

Example 1 70% by weight of activated carbon powder (specific surface area: 1950 m ² / g, average particle size: 10 μm) with phenolic solvent KOH activated, calcined carbon black CB1
Was added to a mixture consisting of 20% by weight and 10% by weight of polytetrafluoroethylene, and kneaded with ethanol, and roll-rolled to a width of 10 cm, a length of 10 cm and a thickness of 0.65 mm.
Was dried at 200 ° C. for 2 hours.

The obtained sheet was punched out to a diameter of 12 mm to produce a polarizable electrode. The coin-type EDLC shown in FIG. 1 was produced using the obtained polarizable electrode. Specifically, the positive electrode 2 and the negative electrode 5 were bonded to the case 1 and the lid 6 of the stainless steel 316 container with a graphite-based conductive adhesive.
After drying these positive and negative electrodes under a reduced pressure of 300 ° C. for 4 hours, the positive and negative electrodes were transferred to a glove box under an argon atmosphere, and impregnated with a propylene carbonate solution containing 1 mol / l of tetraethylammonium tetrafluoroborate. , 5 are opposed to each other and a polypropylene nonwoven fabric separator 4 is interposed therebetween, and then sealed in a container using polypropylene insulating gaskets 3 and 3 to produce a coin-type EDLC shown in FIG. The obtained coin-shaped EDLC had a diameter of 18.3 mm and a thickness of 2.0 mm.

Example 2 A coin-type EDLC as shown in FIG. 1 was assembled in the same manner as in Example 1, except that CB2 was used instead of carbon black CB1.

[Comparative Examples 1 to 3] In Example 1, carbon black CBa was used instead of carbon black CB1.
A coin-type EDLC as shown in FIG. 1 was assembled in the same manner except that (Comparative Example 1), CBb (Comparative Example 2), and CBc (Comparative Example 3) were used.

The obtained EDLCs of Examples 1 and 2 and Comparative Examples 1 to 3 were charged at an applied voltage of 2.5 (V), and were charged by about 0.5 (V).
The initial capacitance (F) and the internal resistance (Ω) when discharged at mA were measured. Table 2 shows the results.

[0057]

[Table 2] From the results in Table 2, it was found that EDLC having excellent characteristics of capacitance and internal resistance can be obtained by using the calcined carbon black having the developed graphite structure of the present invention as the conductive material for the polarizable electrode.

[Brief description of the drawings]

FIG. 1 shows a coin-type EDLC manufactured in Examples and Comparative Examples.
FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case 2 Positive electrode (polarizable electrode) 3 Gasket 4 Separator 5 Negative electrode (polarizable electrode) 6 Top lid

Claims (2)

[Claims] At least one of a positive electrode and a negative electrode is formed of a polarizable electrode containing activated carbon and carbon black, and an electric electrode comprising a separator interposed between the positive and negative electrodes and a non-aqueous electrolyte. A multilayer capacitor, wherein the carbon black is 1800 to 3000 under oxygen-blocking air or vacuum or an inert atmosphere.
An electric double layer capacitor characterized by using a fired carbon black fired at a temperature of ° C. 2. A positive electrode comprising activated carbon and oxygen-blocked air or a vacuum or an inert atmosphere in the range of 1800 to 3000
A non-polarizable electrode containing a carbon material obtained by occluding lithium ions in a carbon material capable of reversibly occluding and releasing lithium ions is used as a negative electrode while using a polarizable electrode containing baked carbon black baked at ℃ and a binder. The electric double layer capacitor according to claim 1, which is used.