Synthesis of CoSe2/Mxene composites using as high-performance anode materials for lithium-ion batteries

Currently, the energy densities of commercial lithium-ion batteries (LIBs) are getting closer and closer to their fundamental limit, and novel anode materials are urgent to be explored to meet the increasing requirements. CoSe2 has a high theoretical specific capacity of 494.4 mAh g−1 and is expected to be a viable anode material for high-power LIBs. However, its actual specific capacity degrades rapidly during the cycling process, while the MXene Ti3C2Tx possesses excellent cycle stability but low specific capacity (about 110 mAh g−1). In this study, novel CoSe2/Ti3C2Tx composites with high specific capacity and good stability were successfully prepared by growing CoSe2 particles in situ on Ti3C2Tx via hydrothermal method. The results showed that after 1000 charge–discharge cycles at a current density of 0.3 A g−1, CoSe2/Ti3C2Tx (with a molar ratio of 1:2) composite still has a high reversible capacity of 210.8 mAh g−1. Excellent rate capability and electrochemical kinetic behavior are also achieved. This study indicates that CoSe2/Ti3C2Tx composites have a promising application prospect in LIBs as an anode material.Graphical abstractA novel CoSe2/Ti3C2Tx composite with high specific capacity and excellent cycling stability is successfully prepared by growing CoSe2 particle on MXene Ti3C2Tx that is derived from the corrosion of Ti3AlC2 by hydrofluoric acid. After 1000 charge–discharge cycles at 0.3 A g−1, CoSe2/Ti3C2Tx composite still possesses a higher reversible capacity of 210.8 mAh g−1.