Research progress on in-situ strategies for modulating the anode/electrolyte interface in zinc-ion batteries

Compared with lithium-ion batteries, aqueous zinc-ion batteries (AZIBs) exhibit remarkable advantages such as lower cost, abundant resources, environmental benignity and higher safety. However, their development is still confronted with several challenges. A critical issue is the poor anode/electrolyte interface performance, which hinders the rapid diffusion of Zn2+ across the interface. While traditional ex-situ modification strategies contribute to interface stabilization, they often face inherent limitations. Problems such as poor solid-solid/liquid interface contact, excessively thick films, and high interface impedance consequently restrict improvements in battery kinetics and long-term cycling performance. In-situ regulation strategies represent a promising solution, as they enhance interface contact, reduce interface resistance and improve ion transport kinetics. This review focuses on the regulation of anode/electrolyte interfaces in AZIBs, and explores interface issues and their evolution mechanisms. It highlights the advantages of in-situ modification technologies in addressing interface problems and systematically organizes their technical frameworks. in-situ regulation strategies are explicitly classified into in-situ polymer electrolytes and in-situ interphase regulation (including in-situ artificial interface layers (AILs) and in-situ solid electrolyte interphase (SEI)), with their definitions, formation mechanisms and functional characteristics clarified. Numerous cases are presented to illustrate the features of in-situ regulation strategies in terms of interface bonding strength, film uniformity, ion transport kinetics and long-term cycling stability. This review underscores the comprehensive advantages of in-situ modification in reducing interface impedance and enhance interface compatibility. Additionally, perspectives and suggestions are presented to guide the future development of high-performance and reliable zinc-based energy storage systems.