Patent ID: 8273478

Claim:
A rechargeable lithium battery, comprising: a negative electrode comprising a negative active material which comprises an active element selected from the group consisting of Si, Sn, Ga, Cd, Al, Pb, Zn, Bi, In, Mg, and Ge; a lithium electrolyte comprising a non-aqueous organic solvent, a lithium salt, and an additive; a positive electrode comprising a positive active material comprising a component that can reversibly intercalating and deintercalating lithium ions; and wherein the negative electrode reacting with the lithium electrolyte, and reversibly forming a lithium-included compound; and the additive comprises an ethylene carbonate-based compound represented by Chemical Formula 1 and a silicon-included compound represented by Chemical Formulae 2 and 4, chemical Formula 1 wherein X and Y are each independently substituents selected from the group consisting of hydrogen, a halogen group, and a fluoroalkyl group with 1 through 5 carbons, X and Y are not hydrogen at the same time, and at least one of X and Y is selected from the group consisting of a halogen group and a fluoroalkyl with 1 through 5 carbons; and wherein R 1 through R 6 are either the same or different, and are independently selected from the group consisting of hydrogen, a halogen group, and a substituted or unsubstituted alkyl group with 1 through 10 carbons.