NONAQUEOUS ELECTROLYTE SOLUTION AND LITHIUM SECONDARY BATTERY

The present invention provides a non-aqueous electrolytic solution for a lithium secondary battery, wherein the lithium secondary battery includes, as a cathode active material, a composite oxide in which at least 35% by mole of a transition metal included in the composite oxide is manganese, and wherein the non-aqueous electrolytic solution includes an unsaturated sultone.