CARBON POWDER AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a cheap carbon powder which can be used for a negative electrode material of a nonaqueous secondary battery wherein the electrolyte can be used at a low temperature and contains a propylene carbonate.

SOLUTION: The carbon powder is obtained by mixing natural graphite powder, which has a ratio R of ≥0.2 and ≤0.5, wherein the ratio R is defined as the ratio of the peak intensity at the neighborhood of 1,360 cm-1to the peak intensity at the neighborhood of 1,580 cm-1of the argon ion laser Raman spectrum, has an average particle diameter of 5-30 μm, and has a specific surface area S1 (m2/g) of ≤20 m2/g, with pitch powder having an average particle diameter of ≤500 μm, in a solid phase and in a ratio of W/S1 of 0.9≤W/S1≤3.0, wherein W is parts of mass of the pitch powder to 100 parts of mass of the natural graphite powder, then heat treating the mixed powder under non-oxidation atmosphere and at 850-1,500°C, and obtaining a carbon powder where the graphite powder is coated with carbon that is fired at a low temperature. The specific surface area S2 (m2/g) of this carbon powder to the specific surface area S1 (m2/g) of the raw material graphite powder satisfies S2/S1≤0.40.

COPYRIGHT: (C)2006,JPO&NCIPI