Polymer Engineering for Stable Zinc Metal Anodes: From Molecular Design to Integrated Strategy

Aqueous zinc-ion batteries (AZIBs) are regarded as a promising energy storage system due to their high safety and low cost. However, the severe dendritic growth, hydrogen evolution reaction (HER), and interfacial corrosion/passivation of zinc metal anodes, which are coupled failure modes, severely limit their cycle life and commercialization progress. Due to their highly tunable molecular structures and inherent multifunctionality, polymer materials offer a systematic solution to these interconnected failure mechanisms. This review aims to elucidate how to achieve synergistic effects through rational polymer design, which encompasses ion transport regulation, side reaction suppression, mechanical buffering, and electrolyte environment optimization. In addition, four main polymer strategies were systematically reviewed: direct modification and protection of the electrode-electrolyte interface with polymer artificial interface layers; conversion of inert separator layers into functionalized components with polymer-modified separators; and upgrading from a physical host to a multifunctional integrated electrode with polymer-based 3D current collectors. Finally, this article points out that future efforts to promote the practical application of high-performance, long-life AZIBs should focus on: the utilization of intelligently designed interfaces, the development of electrolytes with wide voltage windows, the implementation of multiscale computational simulations, and the establishment of sustainable polymer systems.