Synthesis of CoSe 2 /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. CoSe 2 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 Ti 3 C 2 T x possesses excellent cycle stability but low specific capacity (about 110 mAh g −1 ). In this study, novel CoSe 2 /Ti 3 C 2 T x composites with high specific capacity and good stability were successfully prepared by growing CoSe 2 particles in situ on Ti 3 C 2 T x via hydrothermal method. The results showed that after 1000 charge–discharge cycles at a current density of 0.3 A g −1 , CoSe 2 /Ti 3 C 2 T x (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 CoSe 2 /Ti 3 C 2 T x composites have a promising application prospect in LIBs as an anode material. Graphical abstract A novel CoSe 2 /Ti 3 C 2 T x composite with high specific capacity and excellent cycling stability is successfully prepared by growing CoSe 2 particle on MXene Ti 3 C 2 T x that is derived from the corrosion of Ti 3 AlC 2 by hydrofluoric acid. After 1000 charge–discharge cycles at 0.3 A g −1 , CoSe 2 /Ti 3 C 2 T x composite still possesses a higher reversible capacity of 210.8 mAh g −1 .