Patent ID: 8435680

Claim:
A prismatic rechargeable lithium battery comprising: a positive electrode comprising a nickel-based positive active material; a negative electrode comprising a negative active material; and an electrolyte comprising a non-aqueous organic solvent, a lithium salt, a first fluoroethylene carbonate additive, a second vinylethylene carbonate additive, and a third alkane sultone additive, the third alkane sultone additive comprising a C3 to C4 alkane sultone, wherein when the battery is equal to or thicker than 5 mm, a mixing weight ratio of the first fluoroethylene carbonate additive to the second vinylethylene carbonate additive ranges from about 5:1 to about 10:1, and when the battery is thinner than 5 mm, the mixing weight ratio of the first fluoroethylene carbonate additive to the second vinylethylene carbonate additive ranges from about 1:1 to about 4:1.