Role of Hetero-Doped Reduced Graphene Oxide in Suppressing Elemental Dissolution in Manganese Selenide Cathode for Aqueous Zinc-Ion Batteries

Mn chalcogenide cathodes hold great promise for high-capacity applications in aqueous Zinc-ion batteries (AZIBs). However, they face critical challenges, including Mn dissolution and chalcogenide decomposition, which not only degrade performance but also raise environmental concerns. Although the incorporation of reduced graphene oxide (rGO) has shown potential in mitigating these issues, the underlying mechanisms remain unclear. Herein, we synthesize MnSe@rGO composites via a hydrothermal and annealing process, utilizing rGO as a conductive framework to stabilize MnSe nanoparticles and improve the structural integrity and reversibility of the electrode. The resulting composite cathode demonstrates enhanced specific capacity, prolonged cycle life, and robust cycling stability under high current densities. Ex-situ characterizations reveal that rGO effectively suppresses Mn dissolution and prevented Se loss during cycling, thereby maintaining the integrity of the cathode and minimizing corrosion of the Zn anode. Furthermore, first-principles calculations provide deep insights into the interactions at the atomic level, showing that Se-doped rGO exhibits strong adsorption affinity for both Mn³⁺ and Se²⁻, leading to increased structural stability and reduced side reactions. This study highlights the potential of rGO composites in addressing key challenges in Mn chalcogenide cathodes, paving the way for their practical application in environmentally friendly AZIBs.