Two-dimensional heterostructure of MXene-derived V2O5·H2O and graphene with enhanced Zn-ion storage capability

Aqueous rechargeable zinc-ion batteries (ZIBs) are promising candidates for gird-scale energy storage with economic and environmental advantages. Layered hydrated vanadium oxides with multivalent and “lubricating” effect receive much attention in ZIBs. However, the application of them is suffering from the poor intrinsic conductivity and the unstable structure. Herein, a unique 2D/2D heterostructure of δ-V₂O₅·H₂O nanobelts (VO) and reduced graphene oxide (rGO) is designed as cathode for ZIBs (denoted as VOG). The stronger interface coupling and the shorter ion transport pathways impart the VOG electrode impressive stability and fast ions diffusion kinetics. Specifically, the VOG cathode delivers a superior capacity of 342 mAh g⁻¹ at 1 A g⁻¹ and a remarkable rate capability of 280 mAh g⁻¹ at a quite high rate of 10 A g⁻¹. The energy storage mechanism involved is investigated by systematical characterizations. The exploration of such 2D/2D heterostructure materials with strong synergy sheds light on the rational design of high performanced AZIBs.