| 摘要 |
PROBLEM TO BE SOLVED: To improve a low-temperature characteristic, long-term stability and a cycle characteristic by using a nonaqueous solvent containing chloroethylene carbonate and vinylene carbonate. SOLUTION: The content of chloroethylene carbonate in a nonaqueous solvent is set to 0.1-50 wt.%, and the content of vinylene carbonate is preferably set to 0.1-30 wt.%. The nonaqueous solvent can contain cyclic carbonate such as normally used ethylene carbonate and chain carbonate such as dimethyl carbonate in addition to these components. The total quantity of the carbonate selected from a group of the cyclic carbonate and bridge carbonate, chloroethylene carbonate and vinylene carbonate preferably occupies 70 wt.% or above of the nonaqueous solvent. Inorganic acid salt such as LiClO4 or organic acid salt such as LiCF3SO3 is preferably used for the Li salt of an electrolyte dissolved in the nonaqueous solvent. |
