Modulating Zn ²⁺ Coordination Strength and Interfacial Mobility via Tailored Phenolic Additives for High Performance of Aqueous Zn‐Metal Batteries

Abstract Aqueous Zn‐metal batteries (AZMBs) are promising candidates for next‐generation energy storage. For achieving highly reversible Zn anodes by controlling interfacial Zn 2+ diffusion, the targeted exploration of electrolyte additives is crucial. Conventional additives typically exhibit strong coordination with Zn 2+ , which mitigates concentration polarization for planar deposition, but can also cause Zn 2+ retention and uneven dissolution during stripping. This study introduces weakly coordinating additives to achieve a balanced regulation of Zn plating and stripping. By investigating a series of para‐substituted phenols, it is demonstrated that weakly coordinating phenolic additives retain the ability to concentrate solvated [Zn(H 2 O) 6 ] 2+ at the interface, thereby mitigating concentration polarization. Both experimental and computational results confirm that the reduced coordination strength enhances interfacial Zn 2 ⁺ mobility, ensuring a uniform Zn 2+ distribution at the electrode–electrolyte interface. Among the investigated additives, the p‐hydroxyacetophenone (ACETO) exhibits optimal performance, enabling ZnǁZn symmetric cells to achieve an exceptional cycling stability (1281 h at 5 mA cm −2 and 5 mAh cm −2 ) and a high‐rate capability. Furthermore, Zn ǁ I 2 batteries containing ACETO retain 89.5% of their capacity after 2700 cycles. This work establishes weakly coordinating additives as a viable strategy and provides a new design principle for regulating interfacial Zn 2 ⁺ dynamics.