Processable polymers of intrinsic microporosity (PIMs) are emerging as promising candidates for next-generation ion exchange membranes (IEMs). However, especially with high ion exchange capacity (IEC), IEMs derived from PIMs suffer from severe swelling, thus, resulting in decreased selectivity. To solve this problem, we report ultramicroporous polymer framework membranes constructed with rigid Tröger’s Base network chains, which are fabricated via an organic sol–gel process. These membranes demonstrate excellent antiswelling, with swelling ratios below 4.5% at a high IEC of 2.09 mmol g^–1, outperforming currently reported PIM membranes. The rigid ultramicropore confinement and charged modification of pore channels endow membranes with both very high size-exclusion selectivity and competitive ion conductivity. The membranes thus enable the efficient and stable operation of pH-neutral aqueous organic redox flow batteries (AORFBs). This work presents the advantages of polymer framework materials as IEMs and calls for increasing attention to extending their varieties and utilization in other applications.

中文翻译：

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用于 pH 中性水性有机氧化还原液流电池的超微孔 Tröger 基础框架膜

可加工的固有微孔聚合物（PIM）正在成为下一代离子交换膜（IEM）的有希望的候选者。然而，特别是在高离子交换容量 (IEC) 的情况下，由 PIM 衍生的 IEM 会遭受严重膨胀，从而导致选择性下降。为了解决这个问题，我们报道了用刚性 Tröger's Base 网络链构建的超微孔聚合物框架膜，该膜通过有机溶胶-凝胶工艺制造。^{这些膜表现出优异的抗溶胀性，在 2.09 mmol g –1}的高 IEC 下溶胀率低于 4.5% ，优于目前报道的 PIM 膜。刚性的超微孔限制和孔道的带电修饰赋予膜非常高的尺寸排阻选择性和竞争性离子电导率。因此，该膜能够实现 pH 中性水性有机氧化还原液流电池 (AORFB) 的高效稳定运行。这项工作展示了聚合物骨架材料作为 IEM 的优势，并呼吁人们越来越关注扩展其品种和在其他应用中的利用。