共沉淀法制备正极材料LiCoO2及其电化学性能研究

以硝酸钴、氢氧化锂为原料采用共沉淀法合成了钴酸锂超细粉体。通过XRD、SEM研究了粉体的晶体结构、形貌等,表明水相共沉淀法合成的粉体层状结构、晶体发育完善,表面光滑,粒径分布范围窄,大部分颗粒粒径在2~3μm间。充放电循环测试表明,电压平台高,在0.2 C倍率下,首次放电比容量高达189.8 mAh.g-1。电化学性能及阻抗测试表明,在4.027 V/3.829 V一对氧化还原峰,对应于Co2+/Co3+氧化还原反应。

Preparation of LiCoO2 Cathode Material by Co-precipitation and Its Electrochemical Behavior

Cathode material of LiCoO2 was synthesized by co-precipitation using cobalt nitrate and lithium hydroxide as the raw materials.The powders were characterized by XRD and SEM for their crystal structure and morphology,and the results showed that the powders synthesized by co-precipitation had layered structure,perfect crystal growth with smooth surface and uniform particle size distribution in size from 2 to 3μm.Charge-discharge cycle tests showed that the material had a high voltage platform,and the first discharge capacity was as high as 189.8 mAh·g-1 at the 0.2 C rate.Electrochemical impedance study revealed that there existed a pair of redox peaks at 4.027V/3.829V corresponding to Co2+/Co3+ redox reaction.