Rich Alkali Ions Preintercalated Vanadium Oxides for Durable and Fast Zinc-Ion Storage

Vanadium oxides are a promising class of cathode materials for rechargeable aqueous zinc-ion batteries (ZIBs). However, the intrinsically low electrical conductivity and unstable structure of vanadium materials often lead to fast performance degradation. In this work, we report on potassium-rich preintercalated vanadium oxide (K1.1V3O8) as a high-performance cathode material for ZIBs. The K1.1V3O8 cathode exhibits a high specific capacity of 386 mAh g–1 at 0.1 A g–1 and good long-term cycling stability with a capacity retention of 114.9% (180.7 mAh g–1) after 10 000 cycles at 10 A g–1. The DFT calculations reveal a low Zn diffusion barrier and low Bader charge of K in K1.1V3O8, which are responsible for its good rate capability and high storage performance. The demonstration approach of maximizing ZIB performance proves to be an effective way to design promising cathode materials for ZIBs by regulating the appropriate preintercalation metal ions.