Abstract: Spinel lithium manganate samples modified with different proportions of magnesium element were prepared by high temperature solid state reaction.The X-ray diffraction（XRD） analysis indicated that the samples were all spinel structure without impurity phase.The Scanning electron microscopy（SEM） results showed that the size and morphology of all the samples before and after doping made little difference.The results of charge-discharge test showed that the sample had better electrochemical properties when x=0.09 in LiMgxMn2-xO4 .The initial discharge specific capacity was 110.5 mA·h/g， and the specific capacity retention was 91.22% after 50 cycles at 1C rate and 55 ℃.

Key words: lithium manganate, magnesium, doping, electrochemical properties