A rechargeable lithium battery including: a positive electrode including a nickel-based positive active material; a negative electrode including a negative active material; and an electrolyte including a non-aqueous organic solvent, a lithium salt, a first fluoroethylene carbonate additive, a second vinylethylene carbonate additive, and a third alkane sultone additive, wherein when the battery is thicker than about 5mm, 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, or when the battery is thinner than about 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.