Engineering strategies, mechanisms and emerging visualization characterization of Zn anode-electrolyte interfaces...

Zinc (Zn) metal is one of the core anode materials for aqueous Zn batteries. However, dendrite growth and parasitic hydrogen evolution at the Zn/electrolyte interface severely hinder its practical application. Extensive studies have been conducted to address these challenges, with separate reviews focusing on Zn anodes and electrolyte modification strategies. Nevertheless, a systematic overview that specifically focuses on the Zn/electrolyte interface and integrates modification strategies, underlying mechanisms, and research methodologies is still lacking. This article systematically reviews the interfacial modification strategies, mechanisms, and advanced visualization techniques for the Zn/electrolyte interface. First, mainstream interfacial engineering approaches, including anode crystal plane engineering, hydrophobic coating modification, and electrolyte additive regulation, are introduced, with emphasis on their intrinsic mechanisms. Subsequently, advanced visualization characterization techniques applicable to anode-electrolyte systems are summarized from the dual dimensions of spatial and local structural resolution, providing methodological support for probing interface behavior. Finally, future research directions are discussed: (1) with the increase of areal capacity, the regulation effect of the Zn substrate on Zn deposition orientation gradually weakens, while the continuous corrosion of deposited Zn by aqueous electrolytes further diminishes the induction effects. Therefore, synergistic modification of both the Zn anode and electrolyte to optimize material physicochemical properties and tailoring the electric double layer structure may provide a promising strategy to address the challenge of dynamic interfacial stability. (2) Establishing a multi-scale, full-process characterization system capable of real-time tracking of interfacial electrochemical reactions is crucial for revealing interfacial evolution mechanisms and guiding the design of high-performance battery systems.