MOF-303-Functionalized Glass Fiber Separator Enabling Synergistic Ion Flux Regulation and Desolvation Modulation for Durable Aqueous Zinc-Ion Batteries

Abstract Aqueous zinc-ion batteries (AZIBs) have emerged as promising candidates for stationary energy storage owing to their intrinsic safety, low cost, and environmental benignity. However, their practical deployment remains hindered by interfacial instability of the Zn anode, including dendritic growth, hydrogen evolution, and parasitic byproduct formation. Here, an aluminum-based metal–organic framework-functionalized glass fiber separator (MOF-303-GF) is developed to regulate Zn2+ transport and deposition chemistry in AZIBs. With the porous framework and abundant zincophilic binding sites of MOF-303, the modified separator reconstructs the local ion transport environment, improves electrolyte wettability, and delivers a high ionic conductivity of 22.6 mS cm–1 together with a Zn2+ transference number of 0.46. More importantly, MOF-303-GF homogenizes the interfacial electric field and Zn2+ concentration distribution, facilitates desolvation-coupled charge transfer, and induces preferential Zn deposition along the Zn(002) plane, thereby effectively suppressing dendrite growth and side reactions. As a result, the Zn symmetric cell achieves highly reversible Zn plating/stripping for over 3700 h at 2.0 mA cm–2, while the Zn∥Cu cell exhibits a Coulombic efficiency of 99.0%. When paired with a sodium vanadate (NaV3O8, NVO) cathode, the Zn||NVO full cell delivers improved cycling stability and retains 58.5% of its capacity after 1000 cycles. We show an effective separator engineering strategy for coupling ion flux homogenization with interfacial reaction regulation, providing new insights into the design of durable AZIB systems.