| 摘要 |
PROBLEM TO BE SOLVED: To increase charge and discharge capacity and improve initial charge and discharge efficiency and cycle characteristic by mixing prescribed pitch carbonaceous fiber mild and pitch graphite fiber mild as main components. SOLUTION: Pitch carbonaceous fiber mild and pitch graphite fiber mild are obtained by thermal treatments of 2400 deg.C or more and 500-1300 deg.C, respectively. In the both, (a) the average particle size is 10-30μm, (b) the surface oxygen concentration (O/C atomic number ratio) obtained by surface analysis by X-ray photoelectron spectral method is 0.05 or less, (c) the spin concentration quantitatively determined by electron spin resonance is 1×10<17> or less, and (d) the adsorbed moisture ratio by Karl Fischer's method is 1.5wt.% or less. The both are mixed together, whereby the capacity in stabilization is larger than in their independent use, and a carbon material suitable for battery negative electrode which has a high initial charge and discharge efficiency and excellent charge and discharge cycle characteristic can be provided. |
