Abstract: The synthesis technology of LiNi_0.5Co_0.2Mn_0.3O₂，a cathode material for lithium ion battery，was optimized by orthogonal experiment with Ni_0.5Co_0.2Mn_0.3（OH）₂，a spherical ternary precursor and LiOH·H₂O as raw materials.The effects of calcination temperature，holding time，and the amount-of-substance ratio of lithium to metallic elements（total amounts of Ni，Co，and Mn）on the morphology and electrochemical performance of LiNi_0.5Co_0.2Mn_0.3O₂ were systematically investigated.The optimal process conditions were obtained as follows: calcination temperature was 800 ℃，holding time was 12 h，and amount-of-substance ratio of lithium to metallic elements was 1.06.The initial discharge capacities of samples prepared under the optimal conditions were 165.1 mA·h/g and 151.6 mA·h/g at 0.2 C and 1 C，respectively，and they also exhibited good cycling stability.

Key words: Ni_0.5Co_0.2Mn_0.3（OH）₂；LiOH·, H₂O；LiNi_0.5Co_0.2Mn_0.3O₂；lithium ion battery；cathode material