Carbon‐coated Vanadium Oxide Nanoflowers with K⁺ Ions Pre‐embedment as a High‐rate Cathode for Zinc‐Ion Batteries

Abstract Recently, aqueous zinc‐ion batteries have become a promising candidate for energy storage devices due to their low cost, high capacity, and environmental friendliness. However, the low electrical conductivity and irreversible Zn²⁺ intercalation/extraction of cathode materials limit the rate performance and cycling stability of Zn‐ion batteries. Herein, carbon‐coated V₂O₅ nanoflowers with K⁺ pre‐embedment (KVO‐C) were synthesized by hydrothermal and high‐temperature annealing methods, showing enhanced electrical conductivity and crystallinity. Assembled with Zn anode and 2 M Zn(CF₃SO₃)₂ electrolyte, the optimized KVO‐C3 battery achieves a high specific capacity of 389.2 mAh g⁻¹ at a current density of 0.1 A g⁻¹ and retains 85% even with a 50‐fold increase in current density and cycling back to 0.1 A g⁻¹. KVO‐C3 also shows excellent capacity retention of 77% and coulomb efficiency of nearly 100% after 2000 cycles and delivers a high energy density of 209 Wh kg⁻¹ at a power density of 3500 W kg⁻¹.