Dual-cation cross-linked poly (aryl piperidine) membrane for anion exchange membrane water electrolyzer

The Anion Exchange Membrane Water Electrolyzer (AEMWE) had emerged as a research hotspot in the field of clean energy due to its potential for low cost and high efficiency. However, the trade-off between ionic conductivity and long-term alkaline stability of anion exchange membranes (AEMs) severely limited their commercial applications. To address this challenge, this study proposed an innovative dual-cation crosslinking strategy and, for the first time, designed and synthesized a series of cross-linked AEMs based on poly (biphenyl-co-dibenzothiophene piperidine). By introducing hydrophilic cationic crosslinkers, this strategy not only significantly optimized the microphase separation morphology of the membranes and constructed efficient ion transport channels, but also achieved a synergistic improvement in ionic conductivity and mechanical properties. Specifically, the crosslinked membrane PBDB-MP-10 exhibited satisfactory OH – conductivity (126.1 mS cm −1 at 80 °C) and swelling (20.9 % at 80 °C), and maintained good alkali stability with a conductivity retention of 81.1 % after immersion in alkaline solution (2 M NaOH at 80 °C) for 1080 h. Moreover, membrane electrodes composed of PBDB-MP-10 membranes were examined at AEMWE, yielding a current density of 1.09 A cm −2 at 2.2 V and operating consistently at a constant current of 200 mA cm −2 for a duration of 80 h. The outcomes suggested that AEM with dual-cation cross-linking had considerable potential as a material for water electrolysers.