JPS61159721A - Large capacitance capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a large-capacity capacitor, and in particular, to a so-called electric double layer capacitor in which a specific electrode material is used to greatly improve the withstand voltage. It is.

[Conventional technology]

It is conventionally known that a capacitor having a large capacity of several farads can be produced by using a material with an extremely large specific surface area, such as activated carbon, as an electrode and placing it in a suitable electrolyte.

Activated carbon used in these products has traditionally been made from wood, coconut shell, lignin, etc.

[Problem that the invention seeks to solve]

Activated carbon is widely used as the polarizable electrode of the above-mentioned electric double layer capacitor, but even if an organic electrolyte is used in this case, the maximum withstand voltage that can be obtained is about 3 volts.

Today, electric equipment has become widely equipped with a wide variety of functional equipment, and it is of course strongly desired to further increase the withstand voltage of the electronic components and capacitors used for power supply pickup. I am in a situation where I am.

[Means for solving problems]

In view of the above-mentioned circumstances, the inventors of the present invention have conducted intensive studies and found that a mixture of polarizable activated carbon and an organic material having an electrochemical reversible redox function can be used as an electrode material for capacitors. They discovered that it is possible to achieve a high withstand voltage, leading to the present invention.

In the present invention, the above-mentioned organic substance having an electrochemical reversible redox function includes quinone derivatives such as rosebenzoquinone, tetramethylrosebenzoquinone, chloranil, or polymers thereof, dianhydride pyromellitic acid, dichlorochloride, etc. Examples include so-called conductive polymers such as socialururic acid, polypyrrole, polythenylene, folyaniline, polyphenylene, and folyacetylene, and particularly preferred are chloranil, polypyrrole, polythennylene, and polyalinine.

Next, as the polarizable activated carbon used in the present invention, activated carbon obtained from conventionally commonly used wood, coconut shell, etc., or polyphenylene, which is a synthetic polymer,
Naphthalene, anthracene, naphthacene, phenanthrene, pyrene, triphenylene, acepriazine, 3.4
．． 8. Polycyclic hydrocarbon compounds and their polymers such as 9-dibennzopyrene, perylene, picene, plasma polymerized and electrolytically oxidized polymers such as benzene and pyridine, imidazole, indole, benzothiophene, carbazole, acridine, zenatridine, benzothiazole , activated carbon obtained by carbonizing and activating a heterocyclic compound such as benzoxazole, a polymer thereof, etc., and particularly preferably activated carbon obtained by carbonizing and activating polyphenylene as a starting material. .

The mixing ratio of these activated carbons and the above-mentioned organic substance having a reversible redox function is 50 to 90% by weight (hereinafter referred to as %
It is preferably in the range of 50% to 70%, particularly preferably 50% to 70%.

Further, in the present invention, the electrolyte solution for the capacitor may be either an aqueous solution or a non-aqueous solution, but preferably a non-aqueous solution. Such a non-aqueous solution, that is, an organic electrolyte, includes an organic solvent such as 2-methyltetrahydrofuran, tetrahydrofuran, sulfolane, propylene carbonate, tetraethylammonium perchlorate, etc. Examples include those in which tetrabutylammonium chlorate, tetraethylammonium tetrafluoroborate, tetrabutylammonium tetrafluoroborate, lithium perchlorate, lithium tetrafluoroborate, etc. are dissolved.

[For production]

In the capacitor of the present invention, by using the above mixture as an electrode, when an organic electrolyte is used,
The withstand voltage of the capacitor could be improved to about 4 volts. Although the cause of this action and effect has not necessarily been clarified, the above-mentioned organic substances undergo reversible redox in the potential range of 3 to 4 volts, which is the open circuit voltage of the capacitor. This is thought to be because the deterioration of the electrodes and electrolyte is significantly suppressed by this action.

〔Example〕

The present invention will be explained in more detail with reference to Examples below.

Example 1 10% Teflon was added as a binder to 0.15 g of activated carbon powder and 0.05 g of chloranil, and the mixture was mixed uniformly and then press-molded onto a 20 mm diameter aluminum mesh to obtain two electrodes. .

Using this electrode, a button-type cell arranged as shown in FIG. 1 was manufactured. As the electrolyte solution, a perchlorine tetraethylammonium carbonate solution having a concentration of IM was used.

In the top view, (1a) and (lb) are polarizable electrodes, (
2) is a propylene nonwoven fabric separator placed between the electrodes, (3) is a Teflon backing, (4) is an outer case, (
5) is the presser, (6) is the lid, (7) is the electrolyte solution (
8) is aluminum mesh.

The cell capacity was 3.1 Farads, and the current capacity was 6.4 mAh/g when the voltage between the poles was 2 volts. Further, when charging and discharging were repeated at a constant current of 8 mA in the range of 1 V to 4 V, no change in capacity was observed even after 500 cycles.

Example 2 Hydroquinone and formaldehyde were polycondensed by a conventional method to obtain a hydroquinone-formaldehyde polycondensate.

Next, electrodes were made in the same manner as in Example 1 using 0.15 g of activated carbon powder and 0.05 g of the above polycondensate with 10% Teflon added as a binder, and a button-shaped cell similar to that in Example 1 was manufactured. did.

The capacitance of this capacitor is 3.4 Farad and 2V
It showed a current capacity of 6.8 mAh/g from OV to OV. Further, when charging and discharging were repeated at a constant current of 8 mA in the range from IV to 4 V, no change in capacity was observed even after 500 cycles.

Example 3 Pyrrole was placed in an aqueous perchloric acid solution, and polypyrrole doped with perchlorate ions was polymerized by a conventional electrolytic oxidation method.

An electrode was prepared in the same manner as in Example 1 using a mixture of 0.15 g of activated carbon powder, 0.1 g of the polypyrrole obtained as described above, and 10% Teflon added thereto as a binder. type capacitor was manufactured. The capacitance of this capacitor is 3.3 farads, 2
It had a current capacity of 4.5 mAh/g in the range from V to Ov. Further, when charging and discharging were repeated at a constant current of 8 mA in the range of 1 V to 4 V, no change in capacity was observed even after 500 cycles.

Example 4 Two electrode plates were obtained in the same manner as in Example 1 using a mixture of 0.2 g of activated carbon powder and 10% Teflon, and then these electrodes were placed as one node in an aqueous perchloric acid solution. Add aniline to this solution and add 1.0% to the platinum cathode.
A voltage of 2 V was continuously applied for 20 hours. Through this operation, about 50 IIg of polyaniline could be formed on the activated carbon electrode. A capacitor was obtained in the same manner as in Example 1 using the two obtained electrode plates.

The capacity of this capacitor is 3.8 Farads, 2V to O
The current capacity up to V was 6.7 mAh/g.

Further, when charging and discharging were repeated at a constant current of 8 mA in the range of 1 V to 4 V, no change in capacity was observed even after 500 cycles.

Comparative Example 1 A comparative capacitor was manufactured in the same manner as in Example 1 except that 10% of Teflon was added to 0.2 g of activated carbon powder. The capacitance of this capacitor was 3.6 farads, and the current capacity from Ov to 2v was 5 mAh/g.

Further, when charging and discharging were repeated at a constant current of 8 mA in the range of 1 V to 4 V, the capacity gradually decreased as the number of cycles increased, and after 200 cycles, the capacity decreased to 50% of the initial capacity.

(Effects) As described above, the present invention can significantly improve the capacitance and withstand voltage of a capacitor by using the specified electrode material, and can meet the conventional demands as described above.
Furthermore, the value of industrial use is extremely large, as new demand can be expected.

[Brief explanation of drawings]

The drawing is a cross-sectional view of an embodiment of a capacitor according to the present invention. la, lb...polarizable electrode, 4...outer box, 5...
Press 7...electrolyte solution.

Claims (1)

[Claims] A large-capacity capacitor characterized in that a mixture of polarizable activated carbon and an organic material having an electrochemical reversible redox function is used as an electrode material.