In Situ Defect Induction in Close-Packed Lattice Plane for the Efficient Zinc Ion Storage

In situ electrochemical activation brings unexpected electrochemical performance improvements to electrode materials, but the mechanism behind it still needs further study. Herein, an electrochemically in situ defect induction in close-packed lattice plane of vanadium nitride oxide (VN_x O_y ) in aqueous zinc-ion battery is reported. It is verified by theoretical calculation and experiment that the original compact structure is not suitable for the insert of Zn²⁺ ion, while a highly active one after the initial electrochemical activization accompanied by the in situ defect induction in close-packed lattice plane of VN_x O_y exhibits efficient zinc ion storage. As expected, activated VN_x O_y can achieve very high reversible capacity of 231.4 mA h g^-1 at 1 A g^-1 and cycle stability upto 6000 cycles at 10 A g^-1 with a capacity retention of 94.3%. This work proposes a new insight for understanding the electrochemically in situ transformation to obtain highly active cathode materials for the aqueous zinc-ion batteries.