Additive, electrolyte for rechargeable lithium battery and rechargeable lithium battery

An electrolyte for a rechargeable lithium battery, the electrolyte comprising:

• a non-aqueous organic solvent,
• a lithium salt, and
• an additive represented by Chemical Formula 1 or Chemical Formula 2:
• wherein, in Chemical Formula 1 and Chemical Formula 2,
• R1 to R8 are each independently an unsubstituted C1 to C10 alkyl group, an unsubstituted C2 to C10 alkenyl group, an unsubstituted C3 to C10 cycloalkyl group, an unsubstituted C3 to C10 cycloalkenyl group, an unsubstituted C2 to C10 alkynyl group, an unsubstituted C3 to C10 cycloalkynyl group, or an unsubstituted C6 to C20 aryl group,
• R1 to R8 are separately present, or at least one pair of R1 and R2;
• R3 and R4;
• R5 and R6;
• and R7 and R8 are linked to each other to provide an unsubstituted monocyclic aliphatic heterocycle, an unsubstituted polycyclic aliphatic heterocycle, an unsubstituted monocyclic aromatic heterocycle, or an unsubstituted polycyclic aromatic heterocycle, and
• L1 to L4 are each independently an unsubstituted C1 to C20 alkylene group.