| 摘要 |
PROBLEM TO BE SOLVED: To produce graphite powder suitable for negative electrode material of a secondary battery of lithium ion which has a high discharge capacity and a low capacity loss at a low cost. SOLUTION: Carbon material containing B and Ti which is prepared by adding B raw material and Ti raw material before graphitization is subjected to the heat treatment for graphitization and, thereby, the graphite powder which includes B of 0.001-5.0 wt.% and Ti of 0.001-5.0 wt.% is obtained. Preferably, the carbon material is subjected to high speed crushing and/or shear crushing before graphitization or subjected to the heat treatment for oxidation and the heat treatment in inactive gas after graphitization. Thereby, the graphite powder, in which the spacing surface density of the closed structure formed by closing the end parts of c-plane layers of the graphite on the powder surface by two layers increases to 100 pieces/μm or more and which allows extremely high discharge capacity, is provided. |
