N, S-Doped Carbon Dots as Additive for Suppression of Zinc Dendrites in Alkaline Electrolyte

The severe dendrite growth on zinc anode in alkaline electrolyte brings great challenge to the development of zinc-based batteries. It is a simple and effective strategy to inhibit zinc dendrite formation by introducing additives into the electrolyte. In this study, N, S-doped carbon dots (TU-CQDs) were synthesized and used as additives to regulate zinc deposition in a typical KOH electrolyte. The experimental and three-dimensional transient nucleation model disclosed that the special functional groups of carbon dots can change the electrode surface state and the coordination behaviors of zinc species in the electrolyte. Therefore, TU-CQDs can not only inhibit the hydrogen evolution reaction, but also achieve uniform zinc deposition. The in-situ synchrotron radiation X-ray imaging elucidated that TU-CQDs can effectively inhibit the dendrite growth and improve the reversibility of zinc plating/stripping process. This work provides a feasible route for regulating the reversibility of zinc metal anode in alkaline electrolyte.