Ammonium intercalated and oxygen vacancy-modulated vanadium pentoxide for high-performance aqueous zinc-ion batteries

Vanadium-based compounds have emerged as a research priority for the cathode materials of aqueous zinc-ion batteries (AZIBs). However, their practical applications are severely limited by low electronic conductivity and sluggish reaction kinetics. Herein, ammonium intercalated and oxygen vacancy-modulated vanadium pentoxide (O v -N 0.15 VOH) was synthesized via a one-step hydrothermal method. The ammonium ions were intercalated into V 2 O 5 interlayers with an optimized interlayer spacing of 11.7 Å, facilitating Zn ion diffusion. Meanwhile, oxygen vacancies enhanced the electronic conductivity and induced the formation of vanadium mixed valences, promoting Zn 2+ adsorption and migration. The synergistic effect of NH 4 + intercalation and oxygen vacancy reduced the Zn ion diffusion energy barrier and reinforced structural stability. Consequently, the O v -N 0.15 VOH cathode delivered a high specific capacity of 406.8 mAh g −1 at 0.2 A g −1 , a capacity retention rate of 49.8% at 5 A g −1 , and a remarkable cycling stability of 79.6% capacity retention after 2000 cycles at 5 A g −1 . The fabricated Zn||O v -N 0.15 VOH aqueous zinc-ion battery achieved a high energy density of 312.3 Wh kg −1 at 121.5 W kg −1 .