微波共沉淀法制备锂离子电池正极材料LiNi0.8Co0.2O2

采用微波共沉淀法合成了制备LiNi0.8Co0.2O2的前驱体球形α-Ni0.8Co0.2(OH)2，将其与LiOH·H2O混合，在氧气氛围下，用不同的烧结温度分别烧结10小时获得LiNi0.8Co0.2O2正极材料。用XRD、SEM对所制备的正极材料进行结构和形貌分析，用恒流充放电测试材料的电化学性能。结果表明，烧结温度对材料结构和电化学性能影响较大，所合成材料均具有α-NaFeO2的层状结构，烧结温度越高材料结晶越完善。900℃烧结的LiNi0.8Co0.2O2材料初级颗粒结晶最完善而且其二次团聚粒子的平均粒径最小，其表现出的电化学性能也最好，首次放电容量为189.1mA·h·g-1，首次循环放电效率达到92.5%。30循环后放电容量保持在148 mA·h·g-1，显示出较好的循环稳定性。

Preparation and electrochemical properties of LiNi0.8Co0.2O2 cathode material by microwave coprecipitation method

The microwave coprecipitation method was used to synthesize α-Ni0.8Co0.2（OH）2 precursor for preparing LiNi0.8Co0.2O2 cathode material. The precursor α-Ni0 8Co0.2（OH）2 was mixed with LiOH·H2O and then calcined in O2 for 10 h at different temperatures（700℃，800℃，900℃）.XRD，SEM analyses and electrochemical tests were used to study the physical and electrochemical performance of the cathode material. With increasing calcination temperature，the characteristic peaks of the cathode materials became stronger and sharper，corresponding to a perfect crystalization. The results of electrochemical tests indicate that the sample LiNi0.8Co0.2O2（900℃）showed excellent electrochemical properties，with an initial discharge capacity of 189. 1 mA·h·g-1 and an initial discharge efficiency of 92. 5%. After 30 cycles，the discharge capacity was still 148 mA·h·g-1，showing good cyclic stability.