Patent ID: 7374841

Claim:
A cathode active material, comprising: (a) a first oxide powder comprising a first oxide, the first oxide comprising (1) lithium (Li), nickel (Ni) and manganese, (2) a first element MI selected from the group consisting of elements in Group 2 to Group 14, and (3) oxygen, the composition of nickel, manganese and MI being as set forth in Chemical Formula 7 Ni 1-y-z Mn y MI z (Chemical Formula 7) wherein, 0.25≦y≦0.45 and 0.01≦z≦0.30; and (b) a second oxide powder comprising a second oxide comprising (1) lithium, (2) a second element MII comprising nickel and cobalt, (3) manganese, (4) a third element comprising at least one of the elements of Group 2 to Group 14, except for nickel, cobalt and manganese, and (5) oxygen, the composition of the second element MII, manganese and the third element MIII being as set forth in Chemical Formula 8 MII 1-t-u Mn t MIII u (Chemical Formula 8), wherein, 0.05≦t≦0.20 and 0.01≦u≦0.10; and wherein, the cathode active material is the product of a process comprising: adding the first oxide powder to a cathode mixture slurry; adding the second oxide powder to the cathode mixture slurry; and applying the slurry to a cathode current collector, and a specific surface area of the first oxide powder is at least 0.40 m 2 /g to at most 2.0 m 2 /g, and a specific surface area of the second oxide powder is at least 0.10 m 2 /g to at most 2.0 m 2 /g.