Ion exchange membranes are semi-permeable thin films allowing for selective transport of either anions or cations and have wide applications in desalination, wastewater treatment and energy conversion and storage. Poly(aryl piperidinium) polymers are promising materials for a new generation of anion exchange membranes with high chemical stability, although their ionic conductivity remains to be further improved. Here we report a design of branched microporous poly(aryl piperidinium) membranes that combine ultra-high Cl⁻ conductivity (120 mS cm⁻¹ at 80 °C), excellent mechanical and chemical stability and solution processability. At the heart of our rational design is the use of stereo-contorted spirobifluorene monomers to control the topology and orientations of branched chains, achieving balanced rigidity and flexibility. The loose chain packing structure reduces the energy barrier for ion dissociation and diffusion within the polymer networks, which can be processed into large-area membranes aided by a colloidal method. When applied to redox flow batteries, our microporous membranes deliver record-breaking performance at a high current density of 400 mA cm⁻². Our work suggests a feasible strategy for the development of high-performance membranes that will find more applications critical to sustainability.

离子交换膜是半渗透薄膜，可以选择性地传输阴离子或阳离子，在海水淡化、废水处理以及能源转换和储存方面有着广泛的应用。聚芳基哌啶聚合物是具有高化学稳定性的新一代阴离子交换膜的有前途的材料，尽管其离子电导率仍有待进一步提高。在这里，我们报告了一种支化微孔聚（芳基哌啶）膜的设计，该膜结合了超高的 Cl ^-电导率（80 °C 时为 120 mS cm ^-1 ）、优异的机械和化学稳定性以及溶液加工性。我们合理设计的核心是使用立体扭曲的螺二芴单体来控制支链的拓扑和方向，实现刚性和柔性的平衡。松散的链堆积结构降低了聚合物网络内离子解离和扩散的能垒，可以借助胶体方法将其加工成大面积膜。当应用于氧化还原液流电池时，我们的微孔膜在 400 mA cm ^-2的高电流密度下提供破纪录的性能。我们的工作提出了一种开发高性能膜的可行策略，该策略将找到更多对可持续发展至关重要的应用。