Submicro-sized and partially etched V2Al CT as an anode for lithium-ion storage

Vanadium-based MXenes are prospective as anode materials in energy-storage devices including lithium-ion batteries (LIBs) but limited by their charge-discharge capacities. Herein, partially-etched V2AlxCTz with the average particle size of ~400 nm was synthesized using 40 wt% HF or mixed NaF+HCl solutions as etchants, respectively. V2AlxCTz etched by 40 wt% HF for 96 h at room temperature (RT) has more exceptional charge-discharge performances against mixed NaF+HCl solutions, with an average reversible capacity of ~450 mAh g−1 at 0.1 A g−1 in the 120 cycles and ~301.2 mAh g−1 at 0.5 A g−1 after 200 cycles in LIBs. The effect of etchants on electrochemical performances and lithium-ion (Li-ion) storage mechanism of V2AlxCTz was discussed comprehensively. Additionally, a Li-ion full cell using LiFePO4 as cathode has exhibited excellent electrochemical performance (150.4 mAh g−1 at 0.1 C). This work illustrates that partially-etched V2AlxCTz with the submicro-sized distribution is also a promising anode material for LIBs.