Mitigating Mg Anode Passivation in Aqueous Rechargeable Batteries: Insights Into Interfacial Engineering and Electrolyte Design

Aqueous rechargeable magnesium batteries (ARMBs) have attracted increasing attention as promising candidates for next‐generation energy storage systems. However, the practical application of Mg metal anodes in aqueous electrolytes is fundamentally hindered by their spontaneous passivation upon contact with H 2 O, resulting in the formation of electrically insulating MgO/Mg(OH) 2 . This passivation layer severely increases interfacial resistance and blocks reversible Mg 2+ transport, leading to rapid performance degradation and premature anode failure. Consequently, conventional Mg anodes are generally regarded as incompatible with aqueous systems. In this review, recent progress toward enabling reversible Mg electrochemistry in aqueous environments is systematically summarized, with a particular focus on the synergistic design of anode materials and electrolyte systems. Key strategies, including artificial interfacial engineering, in situ alloy formation, and multidimensional electrolyte design (high‐concentration, eutectic, gel/solid‐state, and hybrid aqueous‐organic electrolytes), are critically discussed from both mechanistic and practical perspectives. By establishing correlations between interfacial chemistry, solvation structure, and electrochemical behavior, this review aims to clarify the fundamental challenges associated with Mg anode passivation and highlight viable pathways toward stable and reversible Mg metal anodes in aqueous media. The insights provided herein are expected to guide the rational design of high‐performance, safe, and sustainable ARMBs.