Graphitic nanofibers, which include tubular fullerenes (commonly called 'buckytubes'), nanotubes and fibrils, which are fucntionalized by chemical substitution, are used as electrodes in electrochemical capacitors. The graphitic nanofiber based electrode increases the performance of the electrochemical capacitors.

Graphitic nanofibers in electrochemical capacitors

The present invention relates to capacitors utilizing an electric double layer formed in the interface of polarizable electrodes and an electrolyte By using as the primary material of the polarizable electrodes an activated carbon in which the difference in titration value between the cases where sodium carbonate is used for neutralization titration of the activated carbon and where sodium hydrogencarbonate is used therefor is 0195 meq/g or more to the weight of the activated carbon, the quantity of presence of the acidic functional group II (carboxyl group present as lactone) on the surface of the activated carbon is increased and, as a result, the affinity between the polarizable electrodes and the electrolyte is enhanced, thus providing electric double-layer capacitors low in variation with time and yet large in capacity

Electric double-layer capacitor

Carbonaceous electrode material for secondary battery and process for production thereof

Flexible carbon fiber, carbon fiber electrode and secondary energy storage devices

The present invention relates to a capacitor with a dual electric layer, wherein one electrode of said capacitor is made of a carbon-based porous material while the other electrode is made of a material containing lead sulphate. The capacitor of the present invention exhibits improved specific characteristics and has a lower cost.

Capacitor with dual electric layer

A material is provided for a polarizable electrode. The material comprises a porous carbon material of activated carbon, activated carbon fibers, carbon fibers or powdery carbon as a raw material, wherein the total amount of acid groups of said porous carbon materials is 0.45 to 4.0 μeq/m2 based on the BET surface area of said carbon material. The material is produced by subjecting the porous carbon raw material to dry oxidation treatment in an oxygen atmosphere whereby the total amount of acid groups introduced into said porous carbon material is 0.45 to 4.0 μeq/m2 based on the BET surface area of said material.

Material for polarizable electrode

PURPOSE:To improve the utilization of a surface area, and to obtain large electrical double layer capacitance by using a porous carbon group material, the quantity of alkali-reactive groups on the surface of which is increased, as a polarizable electrode CONSTITUTION:Carbonized carbon fiber cloth is oxidized in air, thus acquiring cloth Total quantity of alkali-reactive groups per the surface area of cloth is represented by 20mueq/m , and electrical double layer capacitance per the surface area is represented by 267muF/cm when an electrolyte as a 4N H2SO4 aqueous solution is used, and represented by 99muF/cm when a IN lithium perchlorate solution dissolved into the mixed solution of propylene carbonate and ethylene glycol dimethyl ether is employed as an organic group electrolyte That is, a porous carbon group material, total quantity of alkali-reactive groups of which extends over 045mueq/m or more to the overall surface area, is used as a polarizable electrode, thus improving the utilization of the surface area, then obtaining the large electrical double layer capacitance per the unit surface area

Toshio Tanaka

Papers

Material for polarizable electrode

Polarizable electrode material