Petoca, Ltd.

Tetsuji Takemura

Mikio Watanabe

Yoshiyuki Nishimura

Akio Takamatsu

Yasuyuki Takai

A process for producing graphite materials for a negative electrode used in a lithium secondary battery which process includes the steps of packing carbon materials having an average particle diameter of 5 to 50 .mu.m in a plurality of boxes, placing the boxes in a graphitization furnace, subjecting the graphite materials to graphitization treatment, and thereafter subjecting the resultant graphite materials to uniformization treatment by mixing and agitation. The above process is capable of decreasing the influence on the qualitative variation of graphite materials ascribed to packing operation into boxes for graphitization, to the position of the materials in a graphitization furnace, and to bubbling phenomenon or the like through graphitization treatment, and is also capable of stabilizing the qualities of the resulting graphite materials and increasing the productivity.

Process for producing graphite material for negative electrode used in

An infusiblized, or infusiblized and slightly carbonized fiber of optically anisotropic pitch type is combined with a phenolic resin fiber to produce a high bulk density carbon fiber structure in the form of a laminate of mutually entangled carbon fiber sheets with improved handleability of fiber sheets and improved stability of a laminate structure formed through entanglement. A high flexural strength carbon-carbon composite material with a high volume fiber content is produced by impregnation with a precursor of carbon and subsequent carbonization of the carbon fiber structure of the kind as described above or a fiber laminate of mutually entangled sheets of the infusiblized, or infusiblized and slightly carbonized fiber of optically anisotropic pitch type blended with the phenolic resin fiber.

Growing community of inventors

Ibaraki-ken, Japan

Tetsuji Takemura