Disclosed is a lithium secondary battery including a positive electrode comprising a combination of positive active materials. The combination includes a material represented by one or both of Formulae 1 and 2; and a material of Formula 3 as follows:
LiaNibMncMdO2 (Formula 1)
where 0.90≦a≦1.2; 0.5≦b≦0.9; 0<c<0.4; 0≦d≦0.2;
LiaNibCocMndMeO2 (Formula 2)
where 0.90≦a≦1.2, 0.5≦b≦0.9, 0<c<0.4, 0<d<0.4, and 0≦e≦0.2;
LiaCoMbO2 (Formula 3)
where 0.90≦a≦1.2 and 0≦b≦0.2; and each M of Formulae 1-3 is independently selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, In, Tl, Si, Ge, Sn, P, As, Sb, Bi, S, Se, Te, Po, and combinations.