Abstract: The modified spinel LiMn2O4 was coated with nano-sized alumina synthesized by homogeneous precipitation method with the ethanol and water as the reaction media.The influences of the amount of coating，ammonia concentration， flow rate，and water bath temperature on the performance of the material were investigated，and the product was also charac- terized by XRD and SEM etc.，the physical and chemical properties and electrochemical performance were tested.Results showed：when reaction media were ethanol and water（volume ratio of 1∶1），amount of coating was 2%（mass fraction of alumina），concentration was 1 mol/L，flow rate of ammonia was 20 mL/min，and water temperature was 55 ℃，then the coating result was the best.The capacity fading rate was only 0.06% under 100 charge and discharge cycles by tests of simulate battery under 55 ℃ at 1C.

Key words: homogeneous precipitation, Al2O3-coating, lithium manganese oxide