A kind of cathode material of layered LixNiyMn1- yO2 characterized with the O2 type has been synthesized by a simple method. Its precursor NaxNiyMn1- yO2 has been prepared from manganese dioxide, nickel hydroxide and sodium carbonate at high temperature in air and quickly cooled in cold water, then it has been exchanged by the melted LiNO3 at 300～ 400℃ in air. The effects of calcine temperature for the precursors and its compositions (the content of Na and Ni) on the electrochemical properties of the material LixNiyMn1- yO2 have been investingated by XRD and electrochemical tests. The results show that the sample Li0.7Ni0.3Mn0.7O2, has the best electrochemical properties which shows only one charge discharge potential stage of 2.8～ 3.0V and has a high specific capacity over 180mAh· g- 1 cycled between 2.0～ 4.20V. A significant structure transformation to the spinal type phase has not been found in the charge discharge cycling and the discharge specific capacity around 165mAh· g- 1 has remained after the 20th cyclings for the material.
