| 摘要 |
PROBLEM TO BE SOLVED: To produce a graphite powder suitable for the negative-electrode material of a lithium secondary battery enhanced in the service capacity and charge and discharge efficiency at normal temps., with the heavy discharge capacity and low-temp. discharge capacity improved and good in charge and discharge efficiency and cycle life. SOLUTION: A carbon material crushed at a high speed before or after carbonization is thermally graphitized or the carbon material crushed before or after carbonization is thermally graphitized, then further theramally oxidized at 600-800 deg.C and heat-treated at >=800 deg.C in an inert gas to produce the graphite powder having a closed structure with the looped end of the C plane layer closed on the surface, with the density of the gap plane between the closed structures in the C-axis direction of graphite at 100-1500 units/μm, with the average particle diameter at weight cumulative 50% obtained by laser diffraction scattering being 5-35μm and having 75μm maximum particle diameter. |
