A rechargeable lithium battery, comprising a positive electrode, a negative electrode, and an electrolyte, the electrolyte comprising a non-aqueous organic solvent, a lithium salt, a first additive, and a second additive, the first additive comprising a compound represented by Chemical Formula 1, the second additive comprising a compound represented by Chemical Formula 2, a derivative thereof, or an adduct thereof, the negative electrode comprising a first negative electrode active material and a second negative electrode active material, the first negative electrode active material comprising a Si-C composite and a first carbon-based negative electrode active material, the Si-C composite comprising a Si-based active material, and the second negative electrode active material comprising a second carbon-based negative electrode active material: wherein, in Chemical Formula 1, X 1 is a halogen atom; Y 1 and Y 2 are each independently O or S; and R 1 and R 2 are each independently H, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a vinyl group, a substituted or unsubstituted C6 to C10 aryl group, or a substituted or unsubstituted C2 to C10 heteroaryl group comprising a hetero atom that is N, O, or P, wherein "substituted" refers to replacement of hydrogen of a compound by a substituent selected from among a deuterium, a halogen, a hydroxyl group, an amino group, a substituted or unsubstituted C1 to C30 amine group, a nitro group, a substituted or unsubstituted C1 to C40 silyl group, a C1 to C30 alkyl group, a C1 to C10 alkylsilyl group, a C6 to C30 arylsilyl group, a C3 to C30 cycloalkyl group, a C3 to C30 heterocycloalkyl group, a C6 to C30 aryl group, a C2 to C30 heteroaryl group, a C1 to C20 alkoxy group, a C1 to C10 fluoroalkyl group, and a cyano group; and wherein, in Chemical Formula 2, Z is N or CH. a positive electrode, a negative electrode, and an electrolyte, the electrolyte comprising a non-aqueous organic solvent, a lithium salt, a first additive, and a second additive, a non-aqueous organic solvent, a lithium salt, a first additive, and a second additive, the first additive comprising a compound represented by Chemical Formula 1, the second additive comprising a compound represented by Chemical Formula 2, a derivative thereof, or an adduct thereof, the negative electrode comprising a first negative electrode active material and a second negative electrode active material, a first negative electrode active material and a second negative electrode active material, the first negative electrode active material comprising a Si-C composite and a first carbon-based negative electrode active material, a Si-C composite and a first carbon-based negative electrode active material, the Si-C composite comprising a Si-based active material, and the second negative electrode active material comprising a second carbon-based negative electrode active material: wherein, in Chemical Formula 1, X 1 is a halogen atom; Y 1 and Y 2 are each independently O or S; and R 1 and R 2 are each independently H, a halogen atom, a substituted or unsubstituted C1 to C10 alkyl group, a vinyl group, a substituted or unsubstituted C6 to C10 aryl group, or a substituted or unsubstituted C2 to C10 heteroaryl group comprising a hetero atom that is N, O, or P, wherein "substituted" refers to replacement of hydrogen of a compound by a substituent selected from among a deuterium, a halogen, a hydroxyl group, an amino group, a substituted or unsubstituted C1 to C30 amine group, a nitro group, a substituted or unsubstituted C1 to C40 silyl group, a C1 to C30 alkyl group, a C1 to C10 alkylsilyl group, a C6 to C30 arylsilyl group, a C3 to C30 cycloalkyl group, a C3 to C30 heterocycloalkyl group, a C6 to C30 aryl group, a C2 to C30 heteroaryl group, a C1 to C20 alkoxy group, a C1 to C10 fluoroalkyl group, and a cyano group; and wherein, in Chemical Formula 2, Z is N or CH.