Large interlayer spacing enabling long life vanadium-based aqueous zinc battery in zinc sulfate electrolyte

Layered vanadium oxides (V2O5) as cathode for aqueous zinc-ion batteries (ZIBs) have attracted a lot of interest due to their large theoretical capacity. However, V2O5 cathode suffers from the collapse of layered structure after long cycles in ZnSO4 electrolyte due to the repeated intercalation/deintercalation of large-size hydrated Zn2+. Herein, we design V2O5 @Phenylbutylamine (V2O5 @PBA) with large interlayer spacing for inexpensive ZnSO4 electrolytes. Between the V-O layers, a remarkable increase in interlayer distance (16.4 angstrom) can be constructed, providing a path for facile hydrated Zn2+ diffusion. The V2O5 @PBA cathode exhibits high specific capacity (387 mAh g-1), superior rate performance and long cycle life (retention of 64 % after 3000 cycles) in ZnSO4 electrolytes, which is much better than that of layered V2O5 cathode (interlayer distance: 11.5 angstrom). These results show that increasing the large interlayer spacing strategy is an effective way to improve the electrochemical performance of vanadium oxide cathode in ZnSO4 electrolyte.