| 摘要 |
PROBLEM TO BE SOLVED: To improve a cycle characteristic of a battery, its electric capacity and storage characteristic in a charged state by including a disulfide derivative in a nonaqueous electrolytic solution prepared by dissolving an electrolyte in a nonaqueous solvent. SOLUTION: This nonaqueous electrolytic solution wherein an electrolyte such as LiPF6 is dissolved in a mixed solvent at a predetermined volume ratio of a solvent having a high dielectric constant such as ethylene carbonate and a solvent having a low viscosity such as dimethyl carbonate contains preferably 0.001-2 wt.% of disulfide derivative expressed by the formula. Thereby, the degradation of battery performance based on the decomposition of the solvent due to oxidation and reduction at charging or the like on the interface between a positive electrode material or the highly- crystallized carbon material of a negative electrode, and the nonaqueous electrolyte solution. This battery is provided with the nonaqueous electrolytic solution, the positive electrode containing an active material such as LiCoO2, and the negative electrode containing an active material such as Li or carbon having a graphite type crystal structure. In the formula, R1 and R2 are each a benzyl group, toryl group, pyridyl group, pyrimidyl group, 1-12C alkyl group or a 3-6C cycloalkyl group. |
