Abstract
Zn-air batteries (ZABs) are promising energy-storage systems owing to their high theoretical energy density, intrinsic safety, and the natural abundance of Zn. However, their practical deployment remains limited by the poor reversibility and interfacial instability of the Zn anode. Unlike a simple plating/stripping electrode, the Zn anode in alkaline ZABs operates through a dissolution–precipitation pathway involving soluble zincate intermediates. As a result, ZnO passivation, dendrite growth, hydrogen evolution, self-corrosion, and electrode shape change are not independent failure modes; rather, they are coupled through nonuniform zincate transport, local ZnO precipitation, and heterogeneous Zn redeposition, leading to progressive active material loss and interfacial degradation. In this review, recent stabilization strategies for Zn anodes are organized into two categories. The first category, interfacial and structural engineering, includes zincophilic interfaces, protective layers, ion-regulating layers, and three-dimensional hosts that regulate the Zn–electrolyte interface, homogenize Zn deposition, and accommodate volume change. The second category, ZnO-centered anode interface design, reframes ZnO from an undesirable, irreversible discharge product to a controllable electrochemically active phase by regulating its formation site, spatial accommodation, dissolution kinetics, and reconversion to metallic Zn. Relevant characterization approaches for elucidating Zn-anode degradation and zincate/ZnO conversion chemistry are also discussed. Finally, the remaining challenges and future directions are discussed, with emphasis on ZAB-specific control of Zn–zincate–ZnO conversion chemistry under practical full cell conditions.