Patent ID: 8753777

Claim:
A cathode composition, comprising: a mixture of (1) a first cathode material comprising a cathode material represented by Formula 1 below: Li x (Co y A m D z )O t (1) wherein 0.8≦x≦1.2, 0≦z≦0.3, 1.8≦t≦4.2, (0.8−m−z)≦y≦(2.2−m−z), 0≦m≦0.3, A is at least one selected from Mg and Ca, and D is at least one selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta; Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Au, Ag, Zn, Cd, Hg, B, Al, Ga, In, TI, C, Si, Ge, Sn, Pb, N, P, As, Sb and Bi; and (2) a second cathode material selected from the group consisting of a second-(a) cathode material and a second-(b) cathode material, and a combination thereof, said second-(a) cathode material comprising a cathode material represented by Formula 2a below: Li x (Ni 1-a-b Mn a Co b ) y O 2 (2a) wherein 0.05≦a≦0.4, 0.1≦b≦0.4, 0.4≦1−a−b≦0.7, 0.95≦x≦1.05, 1.9≦x+y≦2.3; and said second-(b) cathode material comprising a cathode material which contains a transition metal mixture of Ni, Mn and Co, has an average oxidation number of all transition metals except for lithium, larger than +3 and satisfies Equations 2b and 2c below: 1.1< m (Ni)/ m (Mn)<1.5 (2b) 0.4< m (Ni 2+ )/ m (Mn 4+ )<1 (2c) wherein m(Ni)/m(Mn) is a molar ratio of nickel to manganese and (Ni 2+ )/m(Mn 4+ ) is a molar ratio of Ni 2+ to Mn 4+ , wherein a mix ratio of the two cathode materials (first cathode material:second cathode material) is 50:50 to 90:10.