低温预处理对正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2结构与电化学性能的影响

Influences of Low-temperature Pretreatment on Structure and Electrochemical Properties of LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2 Cathode Material

以水热法制备的Li-Ni-Co-Mn-O锂化前驱体为原料,采用两段煅烧法合成了具有α-NaFeO_2型结构的LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2正极材料,通过X射线衍射分析(XRD)、扫描电子显微镜(SEM)和电化学性能测试对不同低温预处理温度制备的正极材料进行了表征。研究结果表明:低温预处理温度为500℃时,制备的正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2具有最优的电化学性能,在3.0~4.3V电压范围内,0.1C下初始容量为169.4mAh/g,0.5C倍率下50次循环后放电比容量为145.3mAh/g,容量保持率高达95.5%。

The cathode material Li LiNi0.5Co0.2Mn0.3O2 with a α-NaFeO2 structure was synthesized through a two-step calcination process with the lithiated precursor of Li-Ni-Co-Mn-O prepared by a hydrothermal process as a raw material.Then,the synthesized cathode materials with pretreatment at different temperatures were characterized by X-ray diffraction（XRD）,scanning electron microscope（SEM） and electrochemical properties analyses. Results show that after pretreatment at a temperature of 500 ℃,the synthesized cathode material LiNi0.5Co0.2Mn0.3O2 exhibits a better electrochemical performance. It delivers a reversible specific capacity of 169.4 m Ah/g in the 1st cycle at 0.1C over 3.0 ~4.3 V and a discharge specific capacity of 145.3 m Ah/g at 0.5C after 50 cycles,with capacity retention up to 95.5%.