Redox flow batteries (RFBs) are promising for long-duration grid-scale sustainable energy storage. The ion-exchange membrane is a key component that determines energy efficiency and cycling stability. However, it remains challenging to develop membranes with high ionic conductivity and high selectivity toward redox-active electrolytes. We report the development of ion-conductive polymer membranes with record-breaking energy efficiency. By incorporating triptycene into poly(ether-ether-ketone) and controlled sulfonation, the resulting intrinsically microporous polymer membranes form highly interconnected water channels that facilitate transport of charge-balancing ions, particularly hydroxide anions. These microporous membranes showed high ionic conductivity without compromising the selectivity toward redox-active species. The membranes enabled excellent performance in alkaline aqueous organic and zinc-iron flow batteries, demonstrating long-term stability, high power density, and an operational current density up to 700 mA cm⁻². The membranes also improved performance in neutral pH aqueous RFBs with high capacity utilization and retention, enhanced energy efficiency, and boosted power density.

中文翻译：

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具有固有微孔性的磺化聚（醚-醚-酮）膜可实现用于储能的高效氧化还原液流电池


氧化还原液流电池 （RFB） 有望实现长期电网规模的可持续能源存储。离子交换膜是决定能源效率和循环稳定性的关键部件。然而，开发具有高离子电导率和对氧化还原活性电解质高选择性的膜仍然具有挑战性。我们报道了具有创纪录能效的离子导电聚合物膜的开发。通过将三苯掺入聚（醚-醚-酮）中并进行受控磺化，所得的本质微孔聚合物膜形成高度互连的水通道，促进电荷平衡离子，特别是氢氧根阴离子的运输。这些微孔膜显示出高离子电导率，而不会影响对氧化还原活性物质的选择性。这些膜在碱性有机水和锌铁液流电池中实现了出色的性能，表现出长期稳定性、高功率密度和高达 700 mA ^cm-2 的工作电流密度。该膜还提高了中性 pH 水性 RFB 的性能，具有高容量利用率和保留率，提高了能源效率，并提高了功率密度。