Cathode materials prepared by a co-precipitation are 0.3Li(2)MnO(3).0.7LiMn(1-x)Ni(y)Co(0.1)O(2) (0.2 <= x <= 0.4) cathode materials with a layered-spinet structure. In the voltage range of 2.0-4.6 V, the cathodes show more than one redox reaction peak during its cyclic voltammogram. The Li/0.3Li(2)MnO(3).0.7LiMn(1-x)Ni(y)Co(0.1)O(2) (x=0.3, y=0.2) cell shows the initial discharge capacity of about 200 mAh g(-1). However, when x=0.2 and y=0.1, the cell exhibits a rapid decrease in discharge capacity and poor cycle life. (C) 2011 Elsevier B.V. All rights reserved.