| 摘要 |
PURPOSE:To increase conductivity and charge-discharge efficiency by using a specific mixed solvent in an electrolyte and specifying the contents of moisture and the other impurities. CONSTITUTION:A negative active material is lithium or a lithium alloy capable of discharge of a lithium ion. A positive active material is a substance which performs reversible reaction electrochemically with a lithium ion. An electrolyte is a solution obtained by dissolving a lithium salt in an organic solvent. As the organic solvent, a mixture of ethylene carbonate and one or more solvents selected from an alkoxy ethane group having a general structural formula indicated in the formula in a volume ratio of 40-90% is used. The moisture contents in the electrolyte are 100ppm or less and the impurity contents other than moisture are 18,000ppm or less. Thereby, charge-discharge capacity, cycle life, and energy density are increased. In the formula, R1 and R2 are the same or different alkyl group having the number of carbons of 1-4. |
