Spinel lithium manganese oxides doped with rare earth elements in forms of LiM 0.02 Mn 1.98 O 4 (M=La, Pr and Sm) were prepared and their electrochemical properties for lithium ion intercalation reaction were investigated. The materials were prepared by solid state reaction using electrolytic MnO 2, Li 2CO 3 with Pr 2O 3, Sm 2O 3 or La(NO 3) 3·H 2O. From the voltammetry test it was found that the reversibility of lithium intercalation reaction could be improved by doping with Sm or Pr into spinel lithium manganese oxides. Although the first discharge capacity was decreased by about 10% for LiPr 0.02 Mn 1.98 O 4 and LiSm 0.02 Mn 1.98 O 4 compounds compared with undoped LiMn 2O 4, but their cycling properties were improved, obviously.
