| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrolyte being excellent in incombustibility and improving the charging/discharging capacity and time cycle characteristic of a battery by containing lithium salts and a lower alkylphosphate whose water content is not higher than a specific value. SOLUTION: A lower alkylphosphate with a water content of 50 ppm or less, represented by the formula, is used. In the formula, R1 , R2 and R3 are each a methyl group or ethyl group, used singly or as a mixture. An example is, e.g. a mixture of trimethylphosphate and triethylphosphate. Ethylene carbonate, dimethyl carbonate, γ-butyrolactone, ethylene glycol sulfite, and the like are also contained as organic solvents when necessary. The lithium salts used are LiCF3 SO3 , LiC4 F9 SO3 , LiPF6 , and the like, their concentrations in an electrolyte being desirably 0.1 to 3 mol /liter. Preferably, the lithium salts are dissolved in the organic solvents containing the lower alkylphosphate to obtain a nonaqueous electrolyte solution for a secondary battery. |
