| abstract |
A lithium secondary battery includes a positive electrode; a negative electrode; and an electrolyte disposed between the positive electrode and the negative electrode, wherein the positive electrode includes a positive active material represented by Formula 1, and the electrolyte includes a lithium salt; a non-aqueous solvent; and a phosphite compound represented by Formula 2, wherein the phosphite compound is present in amount of about 0.1 wt % to about 5 wt % based on a total weight of the electrolyte: n Li x Ni y M 1-y O 2-z A z Formula 1n n n n n n n n n n n n n wherein, in Formula 1, n 0.9≦x≦1.2, 0.7≦y≦0.98, and 0≦z<0.2; n M comprises Al, Mg, Mn, Co, Fe, Cr, V, Ti, Cu, B, Ca, Zn, Zr, Nb, Mo, Sr, Sb, W, Bi, or a combination thereof; and n A is an element having an oxidation number of −1 or −2; n wherein in Formula 2, n R 1 to R 3 are independently an unsubstituted C 1 -C 30 alkyl group or an unsubstituted C 6 -C 60 aryl group. |