Patent ID: 8551662

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 cyclic carbonic ester having an unsaturated bond, and at least one sulfonic compound represented by formula (3) or formula (4): wherein each of R 3 to R 7 independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R 8 represents a hydrocarbon group having 1 to 8 carbon atoms, and n 3 represents an integer of 0 to 4; wherein each of R 9 to R 12 independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, or R 9 and R 10 , R 11 and R 12 each may be combined with each other to form a ring and R 10 and R 11 may be also combined with each other, wherein said cyclic carbonic ester having an unsaturated bond is present in an amount ranging from 0.01 to 10% by weight.