In situ self-sulfidation strategy for ZnO/ZnS/C ternary nanocomposites as ultra-stable anodes for alkaline Zn–Ni batteries

A novel in situ self-sulfidation approach was devised to fabricate ZnO/ZnS/C ternary nanocomposites as highly stable anodes for alkaline Zn–Ni batteries. Zinc sulfate acted as a dual-purpose precursor, providing both zinc and sulfur, whereas acrylamide served as the carbon source and in situ reductant. In a single-step carbothermal pyrolysis at 800 °C, the carbon matrix converted sulfate ions to sulfide, facilitating the simultaneous generation of electrochemically active ZnO, a protective ZnS layer, and a conductive carbon network during a single thermal treatment. The optimized ZnO/ZnS/C-2 electrode exhibited a discharge capacity of 576.8 mAh g −1 after 600 cycles at 1 C and maintained 513.2 mAh g −1 at 15 C. Under identical conditions at 10C, the ZnO/ZnS/C-2 electrode delivered a capacity of 545.3 mAh g −1 , which is 41.5% higher than that of commercial ZnO (385.4 mAh g −1 ). Upon the current density reverting to 0.2 C, it regained 96.6% of its original capacity, indicating remarkable reversibility. Post-cycling scanning electron microscopy images validated the successful inhibition of zinc dendrite proliferation. The performance improvements arise from the synergistic combination of the protective ZnS layer, the interconnected conductive carbon framework, and the advantageous ZnO/ZnS heterointerface, which collectively boost structural stability and charge transfer kinetics.