LiNi0.94Co0.04Al0.02O2正极材料制备及其电化学性能研究

Research on Preparation and Electrochemical Performance of LiNi0.94Co0.04Al0.02O2 Cathode Material

以共沉淀法制备的类球形镍钴铝前驱体Ni0.94Co0.04Al0.02(OH)2与锂盐Li OH·H2O为原料,通过高温固相法制备了球形镍钴铝酸锂Li Ni0.94Co0.04Al0.02O2正极材料,研究了煅烧温度对合成产物结构与性能的影响。采用XRD、SEM和EDS对Li Ni0.94Co0.04Al0.02O2正极材料粉末的结构、形貌和元素分布进行了表征;采用充放电测试和循环性能测试对材料的电化学性能进行研究。结果表明:745℃制备的Li Ni0.94Co0.04Al0.02O2正极材料层状结构较好,Ni、Co、Al三种元素分布均匀,具有最高的放电比容量和优良的循环性能;在2.8~4.3V内,0.1C倍率的首次放电比容量达221.6 m Ah/g,1C倍率下50周循环容量保持率达90%以上。

The spherical LiNi0.94Co0.04Al0.02O2 cathode materials for lithium-ion batteries were synthesized by high temperature solid-state method taking the spherical LiNi0.94Co0.04Al0.02O2(OH)2 and Li OH·H2O as raw materials.The effects of calcination temperature on the structure and properties of the products were investigated.The structure,morphology and element distribution of cathode materials powder were analyzed by X-ray diffraction spectroscopy(XRD),scanning electron microscopy(SEM),energy spectrometer(EDS).The electrochemical properties of the materials were studied by charge-discharge test and cyclic properties test.The results show that LiNi0.94Co0.04Al0.02O2 cathode material prepared at calcination temperature 745℃has good layered structure,with uniform distribution of Ni,Co,Al three elements,and it has the highest discharge specific capacity and good cyclic performance.The initial discharge capacity is 221.6 m Ah/g at charge-discharge rate of 0.1C between 2.8-4.3 V and the discharge capacity retention rate is more than 90%after 50 cycles at a charge-discharge rate of 1C.