Patent ID: 6887622

Claim:
A carbonaceous active material comprising: at least one crystalline graphite core; and an amorphous graphitizable carbon shell coating the outside of the crystalline graphite core wherein a differential thermal analysis conducted on the carbonaceous active material in 10Â° C. increments per minute starting from room temperature and proceeding to 1000Â° C. at atmospheric pressure results in the displaying of at least two exothermic peaks overlapping to form shoulders, the amorphous graphitizable carbon shell coating is derived from an amorphous carbon precursor selected from the group consisting of pitch, coal based oil and heavy oil, and wherein the active material includes at least one crystalline graphite primary particle coated with amorphous carbon, and the at least one crystalline graphite primary particle coated with the amorphous carbon is agglomerated and made into a spherical shape to produce secondary particles.