| 摘要 |
PROBLEM TO BE SOLVED: To impart fire resistance without loosing the charge and discharge efficiency, energy density, output density and life by comprising an electrolyte, a nonaqueous solvent and the quaternary salt of a compound having an asymmetric chemical structure having a nitrogenous conjugate structure. SOLUTION: As a frame retarder, the quaternary salt of a compound having N,N,N'-substituted amidine group, which is a compound of an asymmetric chemical structure having a nitrogenous conjugate structure of the formula, is used. Examples of the salt include 1-methyl-3-ethylimidazorium/borate tetrafluoride, and it is preferably contained in 30-99 wt.%. The electrolyte consists of a lithium borate tetrafluoride or the like, and the nonaqueous solvent consists of propylene carbonate or the like. Accordingly, a flame retardant nonaqueous electrolyte having a high withstand voltage and excellent in electric conductivity characteristic at low temperature can be provided. In the formula, R<1-2> represent a 1-10C hydrocarbon group which may contain an amino group, nitro group, cyano group, carbonyl group or ether group; R<3-6> represent a 1-10C hydrocarbon group which may contain H or an amino group, nitro group, cyano group, carbonyl group or ether group. |
