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 Zn 2+ intercalation/extraction of cathode materials limit the rate performance and cycling stability of Zn‐ion batteries. Herein, carbon‐coated V 2 O 5 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(CF 3 SO 3 ) 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 .