Patent ID: 7575833

Claim:
A nonaqueous electrolyte which comprises a nonaqueous organic solvent and a lithium salt dissolved therein, wherein the nonaqueous organic solvent comprises at least one compound selected from the group consisting of acid anhydrides and carbonic esters having an unsaturated bond and at least one fluorine-containing aromatic compound having 9 carbon atoms or less selected from the group consisting of fluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,3-trifluorobenzene, 1,2,4-trifluorobenzene, 1,3,5-trifluorobenzene, 1,2,3,4-tetrafluorobenzene, 1,2,3,5-tetrafluorobenzene, 1,2,4,5-tetrafluorobenzene, pentafluorobenzene, hexafluorobenzene, 2-fluorotoluene, 3-fluorotoluene, 4-fluorotoluene, 2,3-difluorotoluene, 2,4-difluorotoluene, 2,5-difluorotoluene, 2,6-difluorotoluene, 3,4-difluorotoluene, benzotrifluoride, 2-fluorobenzotrifluoride, 3-fluorobenzotrifluoride, 4-fluorobenzotrifluoride, 3-fluoro-o-xylene, 4-fluoro-o-xylene, 2-fluoro-m-xylene, 5-fluoro-m-xylene, 2-methylbenzotrifluoride, 3-methylbenzotrifluoride, 4-methylbenzotrifluoride, and octafluorotoluene, wherein the total content of the fluorine-containing aromatic compound is 0.01 to 10% by weight based on the nonaqueous electrolyte.