There is provided a negative electrode for a lithium ion secondary battery high in discharge capacity per unit volume, small in capacity loss at the time of initial charge/discharge, and excellent in rapid charge/discharge characteristics.
Natural graphite, rendered spherical in shape, is mixed with carbon black, and pitch is added to a mixture thus formed to be thermally kneaded before baked at a temperature in a range of 900 to 1500°C, thereby obtaining graphite particles (A), each being substantially spherical in shape, and having fine protrusions on the surface thereof. Since the graphite particles (A) have the fine protrusions on the surface thereof, a multitude of electrically conducting networks are built in a complex way within an electrode, the graphite particles (A) can serve as a negative electrode material excellent in rapid charge/discharge characteristics, and power characteristics. The graphite particles (A) further baked at 3000°C to be graphitized are turned into graphite particles (B), each having similarly fine protrusions on the surface thereof. Further, carbonaceous particles (C) are also obtained by baking a mixture of pitch and carbon black in the range of 900 to 1500°C. By mixing those particles together as appropriate, it is possible to increase electrode density, thereby obtaining a lithium ion secondary battery having less deterioration in discharge capacity holding ratio, and excellent cycle characteristics. In accordance with Raman spectroscopic analysis using argon laser Raman scattering light, there exists a G-band composite peak comprising peaks in the vicinity of 1600cm -1 , and 1580cm -1 , respectively, and at least one peak in the vicinity of D-band at 1380cm -1 , an interlayer distance of the lattice plane d 002 , obtained by wide-range X-ray diffraction, being in the range of 0.335 to 0.337nm.