Modifying of Graphite Recovering From the Industrial Diamond Remainders as Value-Added Cathode Material for High-Performance Aqueous Zinc-Ion Batteries

To meet the future development of high-performance aqueous zinc ion batteries (AZIBs) with high energy density, low cost, and excellent cycle stability, an innovative strategy is developed to treat diamond residue graphite and integrate nanostructured MnO₂ onto its surface via simple hydrothermal and heat treatment methods. In the MnO₂@MG composite, the presence of modified graphite (MG) restricts the degree of freedom of MnO₂ growth, resulting in the formation of smaller MnO₂ structures and avoiding the accumulation and aggregation of MnO₂, which helps to improve the interface charge transport of composite electrodes. Meanwhile, the MG could effectively slow the structural collapse of MnO₂ during charging/discharging and improve the conductivity of MnO₂. Based on the synergistic core–shell structure, the AZIBs employing MnO₂@MG exhibit superior capacity (332.0 mA h g⁻¹ at 100 mA g⁻¹ over 300 cycles), excellent rate capabilities (208.1 mA h g⁻¹ at 500 mA g⁻¹), and outstanding cycling performance (48.1% capacity retention after 2000 cycles) at high current density. This work demonstrates the successful and large-scale conversion of industrial diamond residue graphite into a high-performance cathode of AZIBs.