The water diffusivity of polymeric anion exchange membranes (AEMs) plays a critical role in determining the AEM fuel cells (AEMFCs) performance because it generates an imbalance in the amount of water at the anode and cathode. However, the correlation between water diffusivity and the chemical structure of AEMs remains unclear. This study focuses on a series of oligo(ethylene glycol) (OEG) functionalized poly(arylene indole piperidinium) AEMs, in which OEG grafts are directly attached onto the polymer backbones. The polar and flexible OEG side chains afford a microphase-separated morphology, close polymer-chain packing, and extra sites for water–ion transport, resulting in high ion-exchange-capacity (IEC)-normalized conductivity, improved water diffusivity, and dimensional stability. Moreover, these side chains provide excellent ex-situ stability in a 1 M NaOH solution (80 °C) for 1080 h, surpassing the stability of its alkyl side chain counterpart (PITP-C10Q85) by a significant margin. The resultant PITP-OEG-85 with the highest water diffusivity exhibits a highest peak power density of 1.23 W cm⁻² at 80 °C despite its low IEC value and conductivity. In-situ durability tests of this membrane at 0.2 A cm⁻² for 24 h revealed the degradation of piperidinium under harsh conditions (70 % anode relative humidity at 60 °C). This work opens a new avenue for designing highly conductive and alkali-stable AEM materials with high water diffusivity to realize high-performance AEMFCs.

聚合物阴离子交换膜 (AEM) 的水扩散率在确定 AEM 燃料电池 (AEMFC) 性能方面起着至关重要的作用，因为它会导致阳极和阴极处的水量不平衡。然而，水扩散率与 AEM 化学结构之间的相关性仍不清楚。本研究重点关注一系列低聚乙二醇（OEG）功能化聚（亚芳基吲哚哌啶鎓）AEM，其中 OEG 接枝物直接连接到聚合物主链上。极性和柔性的 OEG 侧链提供微相分离的形态、紧密的聚合物链堆积和额外的水离子传输位点，从而产生高离子交换容量 (IEC) 归一化电导率、改善的水扩散率和尺寸。稳定。此外，这些侧链在 1 M NaOH 溶液 (80 °C) 中提供了 1080 小时优异的异位稳定性，大大超过了其烷基侧链对应物 (PITP-C10Q85) 的稳定性。 所得的具有最高水扩散率的PITP-OEG-85在80℃时^{表现出1.23W cm -2}的最高峰值功率密度，尽管其IEC值和电导率较低。该膜在 0.2 A cm ^-2下进行 24 小时的原位耐久性测试表明哌啶在恶劣条件下（60 °C 下阳极相对湿度为 70%）会发生降解。这项工作为设计具有高水扩散率的高导电性和碱稳定性 AEM 材料以实现高性能 AEMFC 开辟了一条新途径。