YAN Zihao, CHEN Qing, LUO Lijie, LI Jianbao, CHEN Yongjun

(School of Materials Science and Engineering, State Key Laboratory of Marine Resource Utilization in South China Sea,Hainan University, Haikou 570228, Hainan, China)

Abstract: CoSe₂ has a high theoretical specific capacity of 494.4 mAh•g⁻¹ and hence is expected to be a viable anode material for high-power lithium-ion batteries (LIBs). However, its actual capacity degrades rapidly during the cycling process. MXene Ti₃C₂T_x possesses excellent cycle stability though its specific capacity is relatively low (110 mAh•g⁻¹). A novel CoSe₂/Ti₃C₂T_x composite with high specific capacity and good stability was successfully prepared by growing CoSe₂ particles in-situ on Ti₃C₂T_x by using hydrothermal method. The effects of hydrothermal temperature and time on morphology and specific capacity of the CoSe₂/Ti₃C₂T_x composite were studied. Phase composition, morphology and structure of the CoSe₂/Ti₃C₂T_x composite were characterized by X-using ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrochemical performances of the CoSe₂/Ti₃C₂T_x composite were examined by using galvanostatic charge-discharge, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). When the hydrothermal temperature is 200 ℃ and the holding time is 16 h, the CoSe₂/Ti₃C₂T_x composite as an anode for LIBs had specific capacity of 180.46 mAh•g⁻¹ even after 1000 charge-discharge cycles at a current density of 0.3 A•g⁻¹.

Key words: CoSe₂; Ti₃C₂T_xMXene; lithium-ion battery; anode material; electrochemical performance