| 摘要 |
PROBLEM TO BE SOLVED: To increase the energy density and improve the cycle characteristic, the load characteristic, and the low-temperature characteristic by containing a specific amount of 3-methyl-2-oxazolidone in nonaqueous electrolyte. SOLUTION: Nonaqueous electrolyte contains 3-methyl-2-oxazolidone represented by a formula by not less than 0.05 vol.% and less than 1 vol.%. As solvent of the nonaqueous electrolyte, preferably, mixture of high-dielectric- constant solvent such as ethylene carbonate or propylene carbonate and chain ester as low-viscosity solvent is used. As the chain ester, especially, dimethyl carbonate, methylethyl carbonate, and diethyl carbonate are adequate. Because the high-dielectric-constant solvent has high dissolving performance of the electrolyte, energy density can be increased. Because the low-viscosity solvent has high transfer performance of electrolyte ions, ion conductivity can be increased. |
