NONAQUEOUS ELECTROLYTE, ELECTROLYTE FOR LITHIUM ION SECONDARY BATTERIES, AND LITHIUM ION SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide: a nonaqueous electrolyte which is high in incombustibility, and enables the improvement of a battery in its discharge load characteristic and cycle characteristic; an electrolyte for lithium ion secondary batteries; and a lithium ion secondary battery.SOLUTION: A nonaqueous electrolyte comprises phosphazene expressed by the chemical formula 1 below. (In the formula 1, at least one of R1 to R6 is at least one alkoxy group selected from a phenoxy group and an ethoxy group, and the rest, i.e. R which is not an alkoxy group is a halogen element). The nonaqueous electrolyte has an ion conductivity of 0.6 s/m or more at 25°C; the ratio (0°C-viscosity/25°C-viscosity) of the 0°C-viscosity of the nonaqueous electrolyte to the 25°C-viscosity thereof is 1.6-2.1.