Disclosed is an electrolyte for a rechargeable lithium battery including 5 to 40 volume % of at least one fluorine-substituted ether compound represented by R1--O--R2 (wherein R1 and R2 are alkyl groups substituted with fluorine), having a substitution ratio of hydrogen with fluorine of 57 to 86%, a viscosity of 0.9 to 2.3 cp, and a boiling point of at least 88.degree. C., and 60 to 90 volume % of a non-aqueous organic solvent having a flash point of at least 80.degree. C.