为提高三元正极材料LiNi_0.5Co_0.2Mn_0.3O₂(NCM523)的可逆比容量和循环稳定性,通过表面包覆聚并苯(PAS)复合钾氯共掺杂对NCM523材料进行双重改性,利用XRD、SEM、TEM等分析方法和恒电流充放电性能测试,研究了不同PAS包覆量复合K、Cl共掺杂NCM523材料的结构、形貌和电化学性能。结果表明,2% PAS包覆复合1% K和Cl共掺的NCM523材料在0.1 C首次放电容量为209.5 mAh/g;1 C倍率下充放电循环100次后放电容量保持率比未改性的NCM523提高了19%;5 C倍率下的放电比容量为158.1 mAh/g,比未改性的NCM523提高了13%。

In order to improve the reversible specific capacity and the cycling stability of LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523),it is dually modified through coated with polyacene (PAS) and co-doped with potassium and chloride.The structure,morphology,and electrochemical properties of NCM523,which are coated with different amounts of PAS and doped with potassium and chloride,are studied by means of XRD,SEM,TEM,and the constant current charge-discharge test.The results show that the NCM523 sample co-doped with 1 mol% K and Cl and coated with 2 wt.% PAS demonstrates the initial discharge capacity of 209.5 mAh·g^-1 at 0.1 C.After both have experienced for 100 cycles of charge-discharge at 1C,the discharge capacity retention rate of the dually modified sample is 19% higher than that of the unmodified NCM523.The specific discharge capacity of the dually modified NCM523 sample is 158.1 mAh·g^-1 under the 5 C ratio,which is 13% higher than that of the unmodified NCM523.

郭金梅(1999-),女,硕士生,研究方向为锂离子电池及其关键材料,guo-jinmei@163.com。