LiMxMn2-xO4 (M = Co, Ni) materials have been synthesized by a melt-impregnation method using gamma-MnOOH as the manganese source. Highly crystallized LiMxMn2-xO4 compounds were synthesized at a calcination temperature of 800 degrees C for 24 h in air. All compounds show a single phase except for LiNi0.5Mn1.5O4 based on the X-ray diffraction (XRD) diagram. With the increase of the doping content from 0.1 to 0.5, the capacity of doping materials decreases mainly in the 4 V region. Although LiM0.5Mn1.5O4 (M = Co, Ni) compound shows a small capacity in the (3 + 4) V region compared with parent LiMn2O4, it is a very effective material in reducing capacity loss in the 3 V region that is caused by the Jahn-Teller distortion. The doping of Co and Ni ions in the LiMn2O4 cathode material promotes the stability of this structure and provides an excellent cyclability.