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

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 Zn2+ 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(CF3SO3)(2) and a cut-off voltage of 0.4 to 1.3V, exhibiting a remarkable capacity of 290mAhg(-1) at 0.5Ag(-1), and long-term cycling stability at high current density. Furthermore, the Zn2+ storage mechanism of V3O7.H2O 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.