GRAPHITE CARBON MATERIAL FOR LITHIUM ION SECONDARY BATTERY NEGATIVE ELECTRODE MATERIAL INCLUDING THEREON GRAPHITE HAVING GRAPHITIZATION HIGHER THAN THAT OF INSIDE GRAPHITE, AND MANUFACTURE THEREOF

摘要

PROBLEM TO BE SOLVED: To use a graphite carbon material having a high capacity and little capacity loss as a negative electrode material for a lithium ion secondary battery, and to pro vide a method for fabricating the same. SOLUTION: This graphite carbon material includes thereon graphite having a graphitization higher than that of inside graphite. By a mechanochemical coating method, a mesophase pitch having a softening point of 300-390 deg.C is applied to the surface of powder obtained by pulverizing needle coke powder or graphite powder obtained by graphitizing the needle coke powder which has an average particle size of 10-20 m, is crushed and grained in a grain size distribution of 2-80 m and has a rate of 90% or more of a needle-like portion to an amorphous portion under the observation by a polarizing microscope, or fiber obtained by carbonizing or graphitizing mesophase pitch fiber or PAN (polyacrylonitrile) fiber, followed by infusibilizing, crushing, carbonizing/burning and graphitizing, thereby obtaining the graphite carbon material including thereon the graphite having a graphitization higher than that of the inside graphite.