| 摘要 |
PROBLEM TO BE SOLVED: To suppress the sudden rise of negative electrode potential in the end of discharge, and prevent the decomposition of an electrolyte by specifying a carbon material used for negative electrode. SOLUTION: As the carbon material in a negative electrode, a multiphase graphite carbon having two or more different crystallinities within one particle and a c-axial crystal element size of 10Å or more is used. The discharge capacity per unit weight is enhanced by the carbon with high crystallinty in the carbon material. On the other hand, the change of potential in the discharge end is made gentle by the carbon with low crystallinity combined into one particle with the carbon with high crystallinity, it is suppressed that a nonaqueous electrolyte is reacted with the carbon material and decomposed by the sudden increase in potential of the negative electrode as in the past, and the cycle characteristic of the battery is improved. |
