CARBON FINE POWDER COATED WITH METAL OXIDE, METAL NITRIDE OR METAL CARBIDE, PROCESS FOR PRODUCING THE SAME, AND SUPERCAPACITOR AND SECONDARY BATTERY USING THE CARBON FINE POWDER

A carbon fine powder is obtained by uniformly coating the surface of a carbon fine powder having a large specific surface area with a uniform thin film layer of a metal oxide, metal nitride or metal carbide as an electrode active substance material through induction of a sonochemical reaction. It is found that the obtained carbon fine powder has a low electrical resistance and shows a rapid faradaic process (pseudo-capacitance) of the surface coating layer. The coated carbon fine powder, a process for producing the same, and a supercapacitor and a secondary battery using the carbon fine powder are disclosed.