| 摘要 |
PROBLEM TO BE SOLVED: To enhance capacity, and to improve a cycle characteristic and a rapid charge/discharge characteristic by performing isotropic pressurizing processing on carbon powder. SOLUTION: When performing isotropic pressurizing processing on carbon powder, bulk density and fluidity are improved, a fluctuation in density of a negative electrode manufactured by using this carbon powder is reduced, and adhesion to a negative electrode current collector is improved. Pressure of this pressurizing processing is desirably set to a range of 50 to 2000 kgf/cm2. The obtained carbon powder is desirably graphite powder on which an interlayer distance d(002) of a crystal is not more than 3.38 Å, the C axis directional crystallite size Lc(002) is not less than 500 Å, the average particle size is 10 to 100 μm, the specific surface area is not more than 8 m2/g, the aspect ratio is 1.1 to 5, a true specific gravity is not less than 2.2 and bulk density is not less than 0.3 g/cm3. The carbon powder as a raw material is not particularly limited, and natural graphite, artificial graphite, amorphous carbon and low temperature processing carbon are cited. |
