Graphene-Supported Mg2+ Intercalated V2O5 Nanoribbons as Cathode for Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) have shown potential applications in energy storage systems due to their lower cost and higher safety, but their performance is strongly influenced by the choice of the cathode material. Herein, we propose V2O5 nanoribbons with reduced graphene oxide (rGO) sheets encapsulating and magnesium ions (Mg2+) inserting between the V2O5 molecular layers. The rGO outside has an excellent electrical conductivity to obtain high reaction kinetically and alleviates the anode dissolution problem, while the magnesium ions inside increase the V2O5 layer spacing and support the molecular layer structure, which finally significantly improves the structural stability. The graphene-supported Mg2+ intercalated V2O5 nanoribbon composite (MVG) electrode delivers the reversible capacity (530 mAh g–1 specific capacity at 0.1 A g–1 current density), unbelievable cycle (89% retention of capacity after 5000 cycles at 5 A g–1), and extraordinary power and energy density (441 Wh kg–1 and 5028.46 W kg–1, respectively). The excellent electrochemical performance proves that MVG is a more suitable cathode material for AZIBs. The combined internal and external modification strategy also provides an idea for the generation of superior cathode materials for AZIBs.