Enhanced charge transfer and reaction kinetics of vanadium pentoxide for zinc storage via nitrogen interstitial doping

Rechargeable aqueous zinc-ion batteries (ZIBs) are the prospective substitution for lithium-ion batteries applied in large scale energy storage system due to their low-cost, environmentally friendliness, and high safety. However, the development of cathodes in aqueous ZIBs suffers from sluggish Zn²⁺ migration. Herein, nitrogen doped V₂O₅ is introduced to resolve the above problem. N-doping lowers the bandgap energy of V₂O₅ to improve its electronic conductivity, and weakens the forces between Zn²⁺ and V₂O₅ to fasten Zn²⁺ diffusion. Further density functional theory (DFT) calculation testifies that N-doping reduces diffusion energy barrier and changes Zn²⁺ diffusion pathway from the vertical interlayer diffusion to planer intralayer diffusion. Meanwhile, the structural stability of electrode material also benefits from the N-doping, which can prevent the interlayer V₂O₅ from gliding or exfoliation during cycling. Profiting from these merits, N-doping V₂O₅ exhibits the outstanding electrochemical properties, such as high rate capability (116.8 mAh/g at 6 A/g) and long cycling performance (3000 cycles at 10 A/g). Dynamics and post-cycling analyses reveal the high capacitive ratio and the stable N distribution in N-doped V₂O₅ during charging/discharging.