Toward reversible Zn electrode: A mechanistic review on interfacial designs in aqueous Zn metal batteries

Abstract

The practical application of aqueous Zn metal batteries (AZMBs) is severely hindered by dendrite growth and parasitic reactions arising from the intrinsic complexity of Zn electrodeposition. During Zn electrodeposition, ion transport, desolvation, nucleation, and crystal growth are strongly coupled, and perturbations introduced at one stage can propagate across subsequent processes, ultimately leading to localized deposition and cell failure. Among various stabilization strategies, artificial interfacial layers are uniquely positioned at the electrode/electrolyte boundary and are therefore able to influence multiple deposition stages simultaneously. However, existing studies primarily categorize interfacial strategies according to material types or individual mechanisms, and the unique ability of interfacial architectures to coordinate the entire deposition sequence remains underappreciated. Consequently, a unified mechanistic framework connecting interfacial functions with overall deposition behavior is still lacking. To address this gap, this review deconstructs Zn electrodeposition into four coupled stages: ion transport, desolvation, nucleation, and crystal growth. For each stage, the underlying mechanisms, kinetic bottlenecks, and corresponding interfacial regulation strategies are systematically discussed. Representative multifunctional interphases are further examined to reveal the opportunities offered by cross-stage regulation. Building upon these insights, design principles based on the coordinated integration of protective interphases and nucleation layers are proposed to optimize the entire deposition sequence, and characterization methodologies are summarized to facilitate stage-specific analysis and mechanistic interpretation. This review provides guiding principles for developing integrated interphases capable of addressing multiple deposition challenges through system-level optimization of Zn electrodeposition.