新合成方法制备的LiCoO_2正极材料的结构和电化学性能研究

Structure and Electrochemical Performance Studies of LiCoO_2 Cathode Material Prepared by New Method

采用新合成方法制备了锂离子二次电池正极材料LiCoO2。通过ICP鄄AES、XRD、SEM、电化学方法等测试分析了所合成材料的物理性质和电化学性能,并与商品LiCoO2材料作了对比研究。同时分别以国产MCMB和石墨作负极活性物质、合成的LiCoO2作正极活性物质做成锂离子电池,对其电化学性能进行了测试。实验结果表明,所合成的LiCoO2材料的电化学性能优于其它两种商品LiCoO2材料,其初始放电容量为155.0mAh·g-1,50次循环后的容量保持率达95.3%,而且以此为正极的锂离子电池也表现出优良的电化学性能。计时电位分析结果还表明,合成的材料在充放电循环过程中发生了三次相转变过程,但相变过程具有良好的可逆性。

LiCoO2 cathode material for lithimn-ion secondary batteries was prepared by new method. The material and other commercial LiCoO2 were characterized and compared by ICP-AES, XRD, SEM and electrochemical testing. And the electrochemical performances of the lithium-Ion batteries using the prepared LiCoO2 as cathode active material and MCMB or artificial graphite as anode active material were studied. The results showed that the prepared material was superior to two commercially available LiCoO2 samples in electrochemical performances, and had an initial charge capacity of about 155.0 mAh . g(-1) and the capacity retention ratio of 95.3% after 50 cycles. The lithium-ion batteries using this material as cathode had excellent electrochemical characterizations as well. The result of differential chronopotentiometry also indicated that three phase transformations occurred during the charge or discharge cycles, and the reversibility of these transformations was good.