o-LiMnO2 is known to have poor cycle performance causing the irreversible phase transformation on cycling. In this paper, the effect of chemical substitution on improving cycle performance of o-LiMnO2 was studied at the compositions of LiCr(x)Mn(1-x)O2 (x=0, 0.1, 0.2, 0.4). XRD is showed that structure of LiCr(x)Mn(1-x)O2 transformed from orthorhombic to spinel according to the increase of substitute degree. For lithium ion battery applications, LiCr(x)Mn(1-x)O2/Li cell were characterized electrochemically by charge/discharge cycling.