Patent ID: 8252465

Claim:
An electrolyte for a lithium secondary battery comprising: a non-aqueous organic solvent comprising at least one cyclic carbonate, at least one linear carbonate, and at least one aromatic hydrocarbon solvent; a sulfone based compound selected from the group consisting of compounds represented by Formulae (I), (II), (III) and mixtures thereof: where R and R′ are independently selected from the group consisting of primary alkyl groups, secondary alkyl groups, tertiary alkyl groups, aryl groups, alkenyl groups; halogen substituted primary alkyl groups, halogen substituted secondary alkyl groups, halogen substituted tertiary alkyl groups, halogen substituted alkenyl groups, and halogen substituted aryl groups, and n is from 0 to 3; where the sulfone based compound is present in an amount from 0.3 to 0.5 wt % on the basis of total weight of the electrolyte; and gamma butyrolactone in an amount from 10 to 30 parts per volume on the basis of 100 parts per volume of the non-aqueous organic solvent.