Highly Reversible Zinc Anode Enabled by a Thiourea‐Derived Protective Layer for Alkaline Zinc Batteries

ABSTRACT Zinc‐based batteries hold great promise as next‐generation energy storage systems due to their low cost, intrinsic safety, and high energy density. However, their long‐term stability and efficiency are severely limited by the irreversible zinc plating/stripping reactions that lead to dendrite growth and parasitic side reactions, such as ZnO formation and hydrogen evolution. Here, we present a simple strategy to stabilize the zinc anode by growing a conjoint zinc sulfide (ZnS) and polymeric carbon nitride (CN) binder‐free protective layer directly on the Zn surface. Structural and electrochemical analyses demonstrate that this hybrid interphase effectively regulates Zn 2+ nucleation, suppresses dendrite formation, and minimizes parasitic reactions, thereby enabling highly reversible zinc cycling with excellent long‐term stability. The optimized Zn anode exhibits a low voltage hysteresis of 170 mV at a high areal capacity of 30 mAh cm −2 (at 30 mA cm −2 ) for over 170 h, achieving more than three times the cycle life of bare zinc. When integrated into a rechargeable zinc–peroxide battery, it delivers state‐of‐the‐art performance, maintaining stable operation for 1100 h at 9 mAh cm −2 .