Few-layer V 2 C/MWCNT with high ionic accessibility for lithium-ion storage.

A V 2 C MXene has a high theoretical capacity and low diffusion barrier, showing tremendous potential in lithium-ion batteries. However, most reports on V 2 C focus on a multilayered structure that is stacked, which diminishes the ionic accessibility and results in unsatisfactory cycling stability. Therefore, we synthesized a few-layer V 2 C (f-V 2 C) material and added multi-walled carbon nanotubes (MWCNTs). The formed f-V 2 C/MWCNT provides abundant pores, which enhance ionic accessibility, so that Li + can easily enter the layer space. The introduction of MWCNTs can further separate the f-V 2 C, expand the specific surface area, reduce the charge transfer resistance, and heighten the structural stability. The experiments reveal that f-V 2 C/MWCNT has a high specific capacity of 531 mA h g -1 at 0.1 A g -1 after 100 cycles. Even at a high current density of 5.0 A g -1 , the specific capacity can still reach 166 mA h g -1 . Moreover, the f-V 2 C/MWCNT structure shows good cycling stability with a capacity retention rate of 95% after 1000 cycles at 5.0 A g -1 . The above findings indicate that f-V 2 C/MWCNT has great application potential in the field of Li + storage.