Polybenzimidazole (PBI)-based ion-solvating membranes (ISM) have gained increasing attention for alkaline water electrolysis (AWE). Herein, we designed a series of sulfonate-grafted poly (2,2’-(1,4-naphthalene)-5,5′-benzimidazole) (NPBI) as ISM materials for AWE application. Through the reaction of NPBI and 1,4-butane sultone, butyl sulfonate side chains with different contents were attached to NPBI backbone to afford NPBI-BS-X polymer. Compared to the pristine NPBI membrane, the introduction of hydrophilic sulfonate side chains showed more KOH liquid absorption (59% for NPBI-BS-47 membrane vs. 45% for NPBI), higher hydroxide conductivity (133 vs. 103 mS/cm), and reduced H₂ permeability (0.51 vs. 2.05 barrer). Ex situ alkaline stability in 8 M KOH at 80 °C demonstrated that 89% of initial conductivity was retained after 1000 h of testing. As a result, the AWE performance of NPBI-BS-47 was evaluated with 6 M KOH at 80 °C, reaching a current density of 1900 mA cm⁻² at 2.0 V, which is much higher than that of the cell with the unmodified NPBI membrane. In the durability test under dynamic operating conditions, the cell with NPBI-BS-47 membrane delivered stable operation for 100 h at a constant current density switching from 0.8 A cm⁻² to 1.6 A cm⁻² after 20 h of operation at each point. The presented design concept of PBI-based polymer offers new opportunities to develop high-performance ISM for alkaline water electrolysis.

基于聚苯并咪唑 (PBI) 的离子溶剂膜 (ISM) 在碱性水电解 (AWE) 领域受到越来越多的关注。在此，我们设计了一系列磺酸盐接枝的聚 (2,2'-(1,4-naphthalene)-5,5'-benzimidazole) (NPBI) 作为 AWE 应用的 ISM 材料。通过NPBI与1,4-丁磺酸内酯的反应，将不同含量的磺酸丁酯侧链连接到NPBI骨架上，得到NPBI-BS-X聚合物。与原始 NPBI 膜相比，亲水性磺酸盐侧链的引入显示出更多的 KOH 液体吸收（NPBI-BS-47 膜为 59%，NPBI 为 45%），氢氧化物电导率更高（133 对 103 mS/cm），并减少 H ₂渗透率（0.51 对 2.05 barrer）。在 80 °C 下，在 8 M KOH 中的非原位碱性稳定性表明，在 1000 小时测试后，89% 的初始电导率得以保留。结果，NPBI-BS-47 的 AWE 性能在 80 °C 下使用 6 M KOH 进行了评估，在 2.0 V 下达到了 1900 mA cm ^-2的电流密度，远高于未改性电池的电流密度。 NPBI 膜。在动态运行条件下的耐久性测试中，采用 NPBI-BS-47 膜的电池在每个点运行 20 小时后，在从 0.8 A cm ^-2到 1.6 A cm ^-2的恒定电流密度下稳定运行 100 小时. 提出的基于 PBI 的聚合物的设计概念为开发用于碱性水电解的高性能 ISM 提供了新的机会。