Patent ID: 8703339

Claim:
A positive active material for a rechargeable lithium battery, consisting of a first positive active material represented by Formula 1 and a second positive active material represented by Formula 2: Li a Ni b Co c M d O 2 Formula 1 wherein 0.95≦a≦1.1, 0.5≦b≦0.9, 0≦c≦0.3, and 0≦d≦0.1, and M is selected from the group consisting of Al, B, Cr, Fe, Mg, Sr, and V; Li e Ni f Co g Mn h O 2 Formula 2 wherein 0.95≦e≦1.1, 0.33≦f≦0.5, 0.15≦g≦0.33, and 0.3≦h≦0.35, wherein the first positive active material comprises a plurality of secondary particles and the second positive active material comprises a plurality of secondary particles, and wherein a weight ratio of the first positive active material to the second positive active material ranges from about 70:30 to about 50:50.