TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The content of the cyano cyclic ester carbonate in the electrolytic solution is 0.01-10 wt.%, and a total content of the compounds (II)-(VI) in the electrolytic solution is 0.001-2 wt.%. Preferred Definitions:    R1-R3=halo such as F, Cl, Br or I, monovalent hydrocarbyl or monovalent halogenated hydrocarbyl including 1-12C alkyl, 2-12C alkenyl, 2-12C alkynyl, 6-18C aryl, 3-18C cycloalkyl or a group obtained by substituting each of part or all of H of each of the groups by halo, monovalent oxygen-containing hydrocarbyl or monovalent halogenated oxygen-containing hydrocarbyl including 1-12C alkoxy or a group obtained by substituting each of part or all of H by halo;    R4-R12=monovalent hydrocarbyl and monovalent halogenated hydrocarbyl including 1-12C alkyl, 2-12C alkenyl, 2-12C alkynyl, 6-18C aryl, 3-18C cycloalkyl or group obtained by substituting each of part or all of H of each of the groups by halo, monovalent oxygen-containing hydrocarbyl and monovalent halogenated oxygen-containing hydrocarbyl including 1-12C alkoxy or a group obtained by substituting each of part or all of H by halo, divalent hydrocarbyl and divalent halogenated hydrocarbyl including 1-12C alkylene, 2-12C alkenylene, 2-12C alkynylene, 6-18C arylene, 3-18C cycloalkylene, a group including an arylene group and an alkylene group, or a group obtained by substituting each of part or all of H of each of the groups by halo, divalent oxygen-containing hydrocarbyl and divalent halogenated oxygen-containing hydrocarbyl including a group including an ether bond and an alkylene group, or a group obtained by substituting each of part or all of H by halo.    SPECIFIC COMPOUNDS - 26 Compounds are specified as the cyano cyclic ester carbonate compound (I) e.g. 2-oxo-(1,3)dioxolane-4-carbonitrile of formula (I'), 5-methyl-2-oxo-(1,3)dioxolane-4-carbonitrile, 5-ethyl-2-oxo-(1,3)dioxolane-4-carbonitrile, 2-oxo-5-phenyl-(1,3)dioxolane-4-carbonitrile and 5-fluoro-2-oxo-(1,3)dioxolane-4-carbonitrile, and 38 compounds are specified as the compounds (II)-(IV) e.g. carbonic acid 2-ethoxycarbonyloxy-ethyl ester ethyl ester, carbonic acid 2-methoxycarbonyloxy-ethyl ester methyl ester, acetic acid 2-(2-acetoxy-ethoxy)-ethyl ester and methanesulfonic acid 2-methanesulfonyloxy-ethyl ester.    EXAMPLE - An electrolytic solution comprising LiPF6 as electrolyte salt, ethylene carbonate + dimethyl carbonate + vinylene carbonate as solvent, cyano cyclic ester carbonate compound i.e. 2-oxo-(1,3)dioxolane-4-carbonitrile (2 wt.%), and LiPF2O2 (0.2 wt.%) as auxiliary compound was prepared. The electrolytic solution when used in secondary battery exhibited cycle retention ratio of 89% and conservation retention ratio of 92%.