NONAQUEOUS ELECTROLYTE ADDITIVE, NONAQUEOUS ELECTROLYTE, AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

The present invention relates to a non-aqueous electrolyte additive that allows for improved safety and battery characteristics of a non-aqueous electrolyte secondary battery, and in greater detail, the present invention relates to a non-aqueous electrolyte additive that includes a phosphazene compound represented by the following general formula (1): €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ(NPR 2 ) n €ƒ€ƒ€ƒ€ƒ€ƒ(1) wherein each R independently represents fluorine or a secondary or tertiary branched alkoxy group substituted with fluorine, at least one of the Rs represents the secondary or tertiary branched alkoxy group substituted with fluorine, and n is from 3 to 14.