Separator Design for High-Performance Aqueous Zinc-Ion Batteries: Recent Advances and Future Outlooks.

Aqueous zinc-ion batteries (AZIBs) have garnered increasing attention as promising candidates for large-scale energy storage applications, owing to their safety, cost-effectiveness, and high theoretical capacity. However, challenges such as dendrite formation, side reactions, and cathode dissolution continue to hinder their widespread adoption. As a critical component in direct contact with both the electrodes and electrolyte, the separator plays a significant role in determining the cycle life of the cell. This review provides a comprehensive review of recent strategies for separator modification, focusing on key approaches such as surface functionalization, regulation of porous structure, and the design of composite matrices. The review highlights the mechanisms by which these modifications influence ion transport, interface stability, and dendrite suppression. Additionally, it explores separator engineering technologies with promising practical applications, bridging the gap between fundamental research and real-world implementation. It is suggested that separator engineering is not only a crucial pathway for enhancing battery performance but also an essential factor for transitioning AZIBs from laboratory-scale research to industrial-scale applications. By analyzing the structure-property relationships of separator materials, this work aims to guide the rational design of next-generation high-performance separators and contribute to the practical deployment of zinc-based energy storage technologies.