ELECTROLYTE, ELECTROLYTE SOLUTION FOR LITHIUM-ION SECONDARY BATTERY COMPRISING THE ELECTROLYTE, AND LITHIUM-ION SECONDARY BATTERY USING THE ELECTROLYTE SOLUTION

摘要

An object of the present invention is to provide an electrolyte solution for lithium-ion secondary batteries comprising a tetraalkylphosphonium salt which improves the cycle characteristics and safety of lithium-ion batteries, and to provide a lithium-ion secondary battery using the electrolyte solution. Disclosed is an electrolyte comprising a tetraalkylphosphonium salt represented by general formula (1) wherein R1 represents a linear, branched or alicyclic alkyl group having 2 to 6 carbon atoms and R2 represents a linear, branched or alicyclic alkyl group having 1 to 14 carbon atoms, provided that R1 and R2 are different from each other and the total number of carbon atoms in the phosphonium cation is 20 or less; and X represents an anion.