A sol-gel method was employed to synthesize LiMn2O4 cathode for lithium ion batteries. Calcination treatment with citric acid results in the reduction of external active materials of the cathode, finally a novel layer coating of MnO was proposed on the surface of LiMn2O4. The structures and morphologies of the as-prepared samples were characterized by XRD, Raman, SEM and HRTEM techniques. It was found that the reaction between LiMn2O4 and citric acid derived carbon occurred during coating process, and the resultant layer was verified to be MnO uniformly coated onto the cathode. Electrochemical performances show that the amount of coating exhibits a significant effect on LiMn2O4 performance, and the optimized MnO coating could exhibit improved battery performance of the LiMn2O4 cathode. The obtained improvement is attributed to decreased Mn dissolution into electrolyte upon cycling resulting from the MnO coating. (C) 2014 Elsevier B.V. All rights reserved.