BaTiO_(3)包覆正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)的改性研究

Modification research of BaTiO_(3) coating on the LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode material

以BaTiO_(3)为包覆层,对正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)的界面变化以及电化学性能进行了研究。本文介绍了BaTiO_(3)包覆正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)的材料结构以及界面状态的变化,分析了不同包覆比例对三元正极材料电化学性能的影响。XRD,SEM和TEM结果表明,BaTiO_(3)包覆并未改变正极材料的层状结构,并且成功包覆在了LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)颗粒表面。电化学表征结果表明,3wt.%BaTiO_(3)包覆的LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2)在50次循环后的R_(ct)(24.5Ω)远小于未包覆的样品(111.8Ω),并且在高截止电压下(2.8~4.5V)表现出较好的界面稳定性和动力学过程,5C倍率下放电比容量达到136.6mAh/g。

The interfacial change and electrochemical performance of the cathode material LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) coated with BaTiO_(3) are studied.This paper introduces the material structure and interface state change of LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode material coated with BaTiO_(3),and analyzes the influence of different coating ratios on the electrochemical performance of ternary cathode materials.XRD,SEM,and TEM results show that the BaTiO_(3) coating does not change the layered structure of the cathode material,and successfully coats on the LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) particle surface;The electrochemical characterization results show that the Rct of LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) coated with 3%BaTiO_(3) after 50 cycles is 24.5Ωwhich is much smaller than that of the uncoated sample(111.8Ω),and the specific discharge capacity of 3wt.%BaTiO_(3) coated LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) reaches 133.6 mAh/g at 5.0 C in the range of 2.8~4.5V and performs better interfacial stability and dynamic process.