Cycling Stability of Alkaline Zinc-Based Batteries Achieved by N, S-Doped Carbon Dot-Decorated Oxygen Vacancy ZnO Anodes

Alkaline zinc-based batteries are promising energy storage devices, whereas uncontrolled side reactions such as dendrite formation and hydrogen evolution reaction (HER) in the anode can significantly affect their discharge capacity and cycle life. In this study, we synthesized N, S-doped carbon dots (N, S-CDs) and ZnO with oxygen vacancies (ZnO_1–x) to prepare ZnO_1–x@N, S-CD composites. The flower-like structure increases the contact between the anode and electrolyte, facilitating the utilization of active material. Oxygen vacancies exhibit a higher electronic conductivity and faster charge transfer, providing more active sites for the reaction. The N, S-CDs on the surface not only enhance the electrical conductivity of the anode but also have a strong adsorption effect on Zn(OH)₄^2–, which is favorable for the uniform deposition of zinc. Consequently, ZnO_1–x@N, S-CDs as an anode can exhibit a high discharge capacity of 595 mAh g^–1 at 5C and maintain a Coulombic efficiency of 90% at 10C for 5000 cycles.