Provided herein is a lithium battery including: a cathode; an anode; and an electrolyte between the cathode and the anode, wherein the cathode includes a cathode active material represented by Formula 1, and the electrolyte includes a lithium salt, a non-aqueous solvent, and a diallyl compound represented by Formula 2:              Li_xNi_yM_1-yO_2-zA_zwherein definitions of x, y, z, M, A, L₁, L₂, and A₁in Formulae 1 and 2 are provided in the detailed description of the present disclosure.