In situ electrochemically activated V₂O₃@MXene cathode for a super high-rate and long-life Zn-ion battery

The development of a high specific capacity and stable vanadium-based cathode material is very attractive for aqueous zinc-ion batteries (ZIBs). Herein, an in situ electrochemically oxidized cathode is fabricated based on a V₂O₃@MXene cathode for Zn-ion storage. V₂O₃@MXene undergoes a phase transition to Zn₃(OH)₂V₂O₇·2H₂O and ZnVO on the first charge, thus allowing for the subsequent insertion/de-insertion of zinc ions, which can be regulated by the amount of H₂O in the electrolyte. The MXene in the composite was also beneficial to electron transfer and cycling stability. V₂O₃@MXene delivered a high capacity of 450 mA h g^-1 at 0.2 A g^-1, ultra-high-rate performance and cycling stability as well as high energy density.