NONAQUEOUS LIQUID ELECTROLYTE FOR USE IN SECONDARY BATTERY, AND LITHIUM-ION SECONDARY BATTERY

摘要

The provision of: a fire-retarding nonaqueous liquid electrolyte, for use in a secondary battery, that results in a lithium-ion secondary battery with excellent rate characteristics; and a safe lithium-ion secondary battery with excellent rate characteristics. This nonaqueous liquid electrolyte comprises a lithium salt and a liquid composition. Said liquid composition contains the following: at least one fluorine-containing solvent (α) selected from the group consisting of fluorine-containing ether compounds, fluorine-containing chain carboxylic acid ester compounds, and fluorine-containing chain carbonate compounds; and a cyclic carboxylic acid ester compound. The lithium salt contains LiPF6, and the lithium-ion diffusion coefficient thereof in this nonaqueous liquid electrolyte at 25°C is at least 1.1×10-10 m2/s.