Fluorine‐Engineered Membranes Break the Conductivity‐Selectivity Trade‐Off in Aqueous Organic Redox Flow Batteries

作者：Qinshan Zhu, Linhan Ni, Kang Peng, Jiaxin Liu, Wenbo Wu, Guifeng Liang, Zhenwei Zhang, Fangmeng Sheng, Peipei Zuo, Tongwen Xu · 发表于：Angewandte Chemie International Edition · 年份：2025 · DOI：10.1002/anie.202510497 · 被引用次数：7 · 研究领域：Advanced battery technologies research、Advanced Battery Technologies Research、Advanced Battery Materials and Technologies

Abstract Ion exchange membranes constitute critical components in aqueous organic redox flow batteries (AORFBs), yet face a fundamental trade‐off. High‐ion‐affinity membranes achieve high conductivity but endure swelling‐induced low selectivity due to co‐uptake of water and organic active species. To address it, we develop a fluorine‐engineered polymer architecture strategy, demonstrated via fluorinated poly(arylene alkylene) anion exchange membranes. Fluorine incorporation 1) establishes interconnected ion channels with suppressed swelling, enabling competitive conductivity at low hydration ( λ < 4.5), and 2) simultaneously reduces redox‐active material affinity, yielding low permeabilities of, for example, 4.0 × 10 −12 cm 2 s −1 for methyl viologen, representing 50‐fold and 425‐fold lower permeability than those of fluorine‐free counterpart and commercial DSV membranes, respectively. The optimized membrane enables a pH‐neutral AORFB exhibiting a low‐capacity decay rate (0.00077% per cycle)–outperforming existing systems by 1–3 orders of magnitude. Our observations provide fundamental guidance for developing advanced membranes in electrochemical energy technologies.