Patent ID: 8778539

Claim:
A secondary battery electrode comprising: a current collector; a first electrode active material layer containing spinel-structured lithium manganate as an electrode active material, the electrode active material being distributed homogeneously through the layer, and being disposed in contact with the current collector; and a second electrode active material layer containing, as the electrode active material, a composite oxide represented by a following Chemical formula ( 1 ), and being stacked on the first electrode active material layer in a thickness direction of the secondary battery electrode, the composite oxide being distributed homogeneously through the layer, wherein an average particle diameter of the composite oxide is smaller than an average particle diameter of the spinel-structured lithium manganate: LiCo v Ni X Mn Y M Z O 2 (1) where M is at least one type selected from the group consisting of Al, Ga and In, V represents an atomic ratio of Co, and is in a range of: 0≦V≦0.5, X represents an atomic ratio of Ni, and is in a range of: 0.3≦X<1.0, Y represents an atomic ratio of Mn, and is in a range of: 0≦Y≦0.5, Z represents an atomic ratio of M, and is in a range of: 0≦Z≦0.1, and v+x+y+z is equal to 1, and wherein the composite oxide comprises LiNi 0 8 Co 0 15 Al 0 05 O 2 .