Hydrated vanadium pentoxide/reduced graphene oxide-polyvinyl alcohol (V2O5⋅nH2O/rGO-PVA) film as a binder-free electrode for solid-state Zn-ion batteries

Recently, solid-state aqueous Zn-ion batteries (ZIBs) have become the most promising wearable storage systems to replace Li-ion batteries owing to their advantages such as high safety and environmental friendliness. However, the critical challenge is to develop stable and robust cathode materials for excellent Zn2+ storage. In this study, a hydrated vanadium pentoxide/reduced graphene oxide-polyvinyl alcohol (V2O5⋅nH2O/rGO-PVA, abbreviated as VOH/rGO-P) film was synthesized as a binder-free cathode for solid-state aqueous ZIBs. The addition of PVA not only increases the layer spacing of VOH and forms a strong hydrogen bond network with GO and water molecules, but also enhances the mechanical properties of the film. As a binder-free cathode for solid-state aqueous ZIBs, the VOH/rGO-P film attains excellent electrochemical capacity as high as 481 mAh∙g−1 at 0.1 A∙g−1. Such a high specific capacity indicates that the VOH/rGO-P film shows great potential for the next generation solid-state aqueous ZIBs.