Rare Earth La <sup> 3 + </ Sup>, The Ce <sup> 3 + </ Sup>-doped Li "li <sub> (1-2x) / 3 </ Sub> Ni <sub> The X </ Sub > <sub> Of Mn (2-x) / 3 </ Sub> O <sub> 2 </ Sub> The Electr

High lithium cathode materials had these performances with high specific capacity, structural stability, and low cost, lower pollution and so on. It was gotten an extensive attention in recent years. The precursor of Li[Li_(1-2x)/3Ni_xMn_(2-x)/3]O₂ was prepared with co-precipitation of sodium hydroxide method. Li[Li_(1-2x)/3Ni_xMn_(2-x)/3]_1-yM_yO₂ as Cathode material of Li-ion battery were synthesized through mixing lithium carbonate with precursor-nickel mang anese lanthanum or cerium hydroxide complex prepared by liquid co-precipitation technique. The high lithium cathode material Li[Li_(1-2x)/3Ni_xMn_(2-x)/3]O₂(x=0.4,0.5) and the high lithium manganese-base cathode materials Li[Li_(1-2x)/3Ni_xMn_(2-x)/3]_1-yM_yO₂(M=Ce,La), and their electrochemical performances were analysed in the paper. The morphology and structure for the cathode materials Li[Li_(1-2x)/3Ni_xMn_(2-x)/3]_1-yM_yO₂(M= Ce,La) were determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. And the charge and discharge performance were measured by electrochemical performances test. SEM show the morphology of most materials are about 200nm. Most of materials were lamelleted structure when y≤0.02.Otherwise ,there were some impurity such as LaNiO3 or CeO2.The intial discharge capacity of Li[Li_0.067Ni_0.4Mn_0.533]O₂,Li[Li_0.067Ni_0.4Mn_0.533]_0.96Ce_0.04O₂ andLi[Li_0.067Ni_0.4Mn_0.533]_0.96Ce_0.04O₂ was 136.6mAh/g ,144.2mAh/g and 148.3mAh/g respectively(25℃,2.75⁴.6V forming, 2.75⁴.2V cycle,1C rate). The rate of discharge capacity were 93%,90%and 92%respectively after 50 cycles. The optimal synthesis conditions were that, the lithium ratio at 1.03 and calcining temperature at 950℃ofLi[Li_0.067Ni_0.4Mn_0.533]_0.96Ce_0.04O₂ ,Li[Ni_0.5Mn_0.5]_0.995Ce_0.005O₂ and Li[Li_0.067Ni_0.4Mn_0.533]_0.99La_0.01O₂ at 900℃could obtain more excellent electrochemical performances.The results showed doping with a certain amount of rare earth elements can stabilize struction of cathode material and improve electrochemical performance.