Organic electrolytic solution comprising an additive, and lithium battery comprising the organic electrolytic solution

An additive for an electrolyte of a lithium battery, the additive being a nitrile-based compound represented by Formula 1 below, an organic electrolyte solution including the additive, and a lithium battery including the organic electrolyte solution are provided: In Formula 1, R is either an unsaturated functional group selected from an unsubstituted or substituted C2-20 alkenyl group, an unsubstituted or substituted C2-20 alkynyl group, an unsubstituted or substituted C6-C40 aryl group, and an unsubstituted or substituted C2-C40 heteroaryl group, or a polar functional group including a heteroatom; and [0002] X is a C2-20 alkylene group optionally substituted by one or more groups selected from an unsubstituted or substituted C2-20 alkyl group, an unsubstituted or substituted C3-12 cycloalkyl group, an unsubstituted or substituted C2-20 alkenyl group, an unsubstituted or substituted C2-20 alkynyl group, an unsubstituted or substituted C6-C40 aryl group, an unsubstituted or substituted C2-C40 heteroaryl group, and a polar functional group including a heteroatom.