| 摘要 |
PURPOSE:To improve the cycle characteristic and self-discharge characteristic by using a carbon material not having the p-doping characteristic by negative ions and having the specific surface area by BET equation and values of the crystal thickness and true density by x-ray diffraction within the specific ranges. CONSTITUTION:A carbon material having no or poor p-doping characteristic has the n-doping characteristic, i.e., is excellent as a negative electrode. There fore, the carbon material never or hardly p-doped electrochemically and reversi bly by negative ions of an electrolyte is used as a negative electrode active material, and the specific surface area A(m<2>/g) by BET equation is made larger than 0.1 and less than 100. Values of the crystal thickness Lc(Angstrom ) and true densi ty (g/cm<2>) are set within ranges: 1.70<rho<2.18 and 10<Lc<12rho-189. Thereby, the cycle characteristic and self-discharge characteristic under the high- temperature environment is improved. |
