Rational In Situ Fabrication of ZnMoO4 Shielding Layers to Mitigate Zinc Degradation and Extend Battery Lifespan

Aqueous zinc-ion batteries (AZIBs) have garnered extensive attention owing to their high theoretical capacity, cost-effectiveness, and intrinsic safety. However, the practical deployment of AZIBs is severely hindered by deleterious side reactions, including surface corrosion, hydrogen evolution, and uncontrollable dendrite growth on the metallic Zn anode. In this work, we propose a simple one-step immersion strategy to in situ construct a ZnMoO4 (ZMO) protective coating on the Zn electrode. Mechanistically, the ZMO layer with polar surfaces exhibits a preferential adsorption affinity towards water molecules and Zn2+ ions. This synergistic adsorption behavior serves a dual function: it effectively excludes active water from the electrode surface to suppress hydrogen evolution, and simultaneously, the strong interaction with Zn2+ lowers the desolvation energy barrier, facilitating rapid Zn2+ desolvation at the interface. Furthermore, the resulting ZMO coating promotes a homogenized surface electric field and provides abundant nucleation sites, thereby guiding uniform Zn deposition and effectively mitigating dendrite formation. Consequently, the ZMO-modified Zn anode delivers significantly enhanced electrochemical reversibility and long-term cycling stability. This work provides a cost-effective and industrially viable surface engineering strategy to tackle the fundamental challenges of Zn anodes, paving the way for the commercialization of high-performance AZIBs.