Advanced Capacitor Technologies, Inc.

Jeol Ltd.

Katsumi Koike

Makoto Takeuchi

Akinori Mogami

Takamichi Maruyama

The present invention provides a novel carbon material for a electric double-layer capacitor having characteristics entirely different from prior art activated carbon. The capacitor develops a capacitance by a mechanism entirely different from the mechanism of an electric double-layer capacitor using activated carbon. The novel capacitor has improved performance including capacitance. The capacitor has polarized electrodes immersed in an organic electrolyte. The electrodes are made of a nonporous carbon having crystallites of graphite-like carbon. When a voltage is applied, electrolyte ions are intercalated between the layers of the crystallites of the graphite-like carbon together with the solvent. Thus, electric double layers are formed. Intercalation is induced by the first cycle of charging. In the second and following cycles, the capacitance is developed.

Carbon material and method of making same

Present invention relates to an electric double-layer capacitor having positive and negative electrodes containing nonporous carbon as an electrode active material. In the nonporous carbon, multiple layers of graphene having an average interplanar spacing dof 0.350 to 0.380 nm have been grown well. The positive and negative electrodes are impregnated with an electrolyte solution. The nonporous carbon is obtained by activating easily graphitizable carbon, which in turn is obtained by calcining needle coke or pitch made infusible. The elctrolyte solution is either a liquid electrolyte having a planar molecular structure or an electrolyte solution consisting of a liquid electrolyte dissolved in an organic solvent.

Electric double-layer capacitor

The present invention provides a novel electric double-layer capacitor made of a carbon material having characteristics entirely different from those of the prior art activated carbon. The capacitor develops a capacitance by a mechanism entirely different from the mechanism of an electric double-layer capacitor using activated carbon. The novel capacitor has improved performance including capacitance. The capacitor has polarized electrodes immersed in an organic electrolyte. The electrodes are made of a nonporous carbon having crystallites of graphite-like carbon. When a voltage is applied, electrolyte ions are intercalated between the layers of the crystallites of the graphite-like carbon together with the solvent. Thus, electric double layers are formed. Intercalation is induced by the first cycle of charging. In the second and following cycles, the capacitance is developed.

Growing community of inventors

Tokyo, Japan

Katsumi Koike