Innovative integrated carbon paper supported Bi/rGO/MnO2 cathode with dual redox reactions for aqueous zinc-ion batteries

Developing cathode materials with dual redox reactions is an effective strategy to improve the electrochemical performance of aqueous zinc-ion batteries (AZIBs), and rational selection of the two electroactive components is the key to achieving this target. Herein, an integrated carbon paper supported Bi/rGO/MnO₂ cathode is prepared via a two-step in situ growth process, in which metallic bismuth (Bi) and manganese dioxide (MnO₂) are served as two types of electroactive components to realize dual redox reactions. The introduction of reduced graphene oxide (rGO) mitigates the interfacial mismatch of Bi and MnO₂, meanwhile further increasing the electrochemical activity by reducing the size of Bi and preventing its self-aggregation. Featuring nanostructured Bi and MnO₂, the integrated cathode enables dual redox reactions with enhanced reaction kinetics. This structural and compositional refinement of the Zn//Bi/rGO/MnO₂ battery leads to superior electrochemical performance, evidenced by a significant specific capacity (388.3 mAh g⁻¹ at 0.1 A g⁻¹), high energy density (464.6 Wh kg⁻¹) and great rate performance. This work underscores the potential of using MnO₂ and Bi as dual electroactive components for AZIBs cathode, providing a pathway towards high performance energy storage systems.