| 摘要 |
PROBLEM TO BE SOLVED: To stably and definitely manufacture a graphite powder for a material for negative electrodes of lithium ion secondary batteries which has a discharge capacity of >350 mAh/g and a high charging and discharging efficiency of >=95%, and retains its high charging and discharging efficiency even at large current discharging or low-temperature discharging. SOLUTION: Tar and/or pitch is heated under a pressure equal to or lower than the atmospheric pressure at from 150 to 600 deg.C. The obtained volatile fraction is mixed with tar and/or pitch when required and allowed to react with an acid at from 100 to 350 deg.C. The reaction product is mixed with tar and/or pitch when required and heated at from 400 to 600 deg.C to obtain a bulk mesophase carbon having an anisotropic domain size of >=1,300 Å. This bulk mesophase carbon is subjected to grinding, carbonization and graphitization to manufacture a graphite powder. Grinding is conducted prior to graphitization through at least one means chosen from high-speed grinding and high-shear grinding. |
