There is provided an electrolytic solution causing no phase separation even at low temperatures, being excellent in
flame retardancy and noncombustibility, assuring high
solubility of an
electrolyte salt, having a high
discharge capacity, being excellent in charge-
discharge cycle characteristics and being suitable for electrochemical devices such as
lithium ion secondary batteries. The electrolytic solution comprises a
solvent (I) for dissolving an
electrolyte salt comprising a
fluorine-containing
ether (A) represented by the formula: Rf1—O—Rf2 (Rf1 and Rf2 are the same or different, Rf1 is a
fluorine-containing
alkyl group having 3 to 6 carbon atoms, Rf2 is a
fluorine-containing
alkyl group having 2 to 6 carbon atoms), at least one fluorine-containing
solvent (B) selected from the group consisting of a fluorine-containing cyclic
carbonate (B1) and a fluorine-containing
lactone (B2), and at least one non-fluorine-containing
carbonate (C) selected from the group consisting of (C1) a non-fluorine-containing cyclic
carbonate and (C2) a non-fluorine-containing chain carbonate, and an
electrolyte salt (II), and the
solvent (I) for dissolving an electrolyte salt comprises 20 to 60% by volume of the fluorine-containing
ether (A), 0.5 to 30% by volume of the fluorine-containing solvent (B), and 5 to 40% by volume of the non-fluorine-containing cyclic carbonate (C1) and / or 10 to 74.5% by volume of the non-fluorine-containing chain carbonate (C2) based on the whole solvent (I).