Layered hydrated vanadium oxide as highly reversible intercalation cathode for aqueous Zn‐ion batteries

Abstract Aqueous Zn‐ion batteries (ZIBs) hold great potential in large‐scale energy storage systems due to the merits of low‐cost and high safety. However, the unstable structure of cathode materials and sluggish (de)intercalation kinetics of Zn 2+ pose challenges for further development. Herein, highly reversible aqueous ZIBs are constructed with layered hydrated vanadium oxide as a cathode material. The electrochemical performances are further tested with the optimized electrolyte of 3M Zn(CF 3 SO 3 ) 2 and a cut‐off voltage of 0.4 to 1.3 V, exhibiting a remarkable capacity of 290 mAh g −1 at 0.5 A g −1 , and long‐term cycling stability at high current density. Furthermore, the Zn 2+ storage mechanism of V 3 O 7 ⋅H 2 O is recognized as a highly reversible (de)intercalation process with good structural stability, implying the potential application in the field of large‐scale energy storage.