NON-AQUEOUS ELECTROLYTIC SOLUTION AND LITHIUM SECONDARY BATTERY

A non-aqueous electrolytic solution containing a ketone compound having the formula (I): Äeach of R and R independently represents a linear or branched alkyl group; and each of R, R, R and R independently represents a hydrogen atom or a linear or branched alkyl group; provided that R and R can be combined to form a cycloalkanone ring in conjunction with a propanone skeleton to which R and R are connected, that two or more of an alkyl group of R, an alkyl group of R, a branched chain of an alkyl group of R, and a branched chain of an alkyl group of R can be combined to form a cycloalkane ring, or that an alkyl group of R and an alkyl group of R and/or an alkyl group of R and an alkyl group of R can be combined to each other to form a cycloalkane ringÜ is favorably employed as a constituent material for preparing a lithium secondary battery that is excellent in the battery performances and cycle performance.