MIXED CARBON MATERIAL AND NEGATIVE ELECTRODE FOR NONAQUEOUS SECONDARY BATTERY

The present invention provides a mixed carbon material which comprises carbon material A and carbon material B and which is a carbon material suitable for a negative electrode material which can provide a nonaqueous secondary battery having a low irreversible capacity and having a negative electrode with a high capacity and high charge acceptance. Carbon material A and carbon material B both have cores made of graphite powder and a surface carbon material in the form of at least one of amorphous carbon and turbostratic carbon adhered to or coated on at least a portion of the surface of the graphite powder. The compressed density is 1.80 - 1.90 g/cm 3 for carbon material A alone, 1.45 - 1.65 g/cm 3 for carbon material B alone, and 1.75 - 1.84 g/cm 3 for the mixed carbon material. The average particle diameter of carbon material B is at most 14 µm and is smaller than the average particle diameter of carbon material A. The specific surface areas of carbon material A and carbon material B are at most 4 m 2 /g and at most 6 m 2 /g, respectively.