Branched‐Crosslinked Anion‐Exchange Membranes With Synergistic Effect for Water Electrolysis

ABSTRACT Anion exchange membrane water electrolysis (AEMWE), which utilizes an anion exchange membrane (AEM) as its core component, is a highly efficient and low‐cost approach for green hydrogen production. In recent years, membrane materials based on polyaromatic frameworks have attracted considerable attention and undergone extensive research in the field of AEM development due to their outstanding resistance to alkalis and robust mechanical properties. This study focuses on the application of branched Poly(p‐terphenyl isatin) structures in the construction of excellent AEMs. By utilizing multi‐cation crosslinkers to create efficient ionic conduction channels and introducing side‐chain structures containing dipole groups and hydroxyl groups to further enhance the AEM's dimensional stability, ionic conductivity, and durability under high‐temperature and strong alkali conditions. The cPTTI‐30 exhibits an OH − conductivity of 159.1 mS cm −1 (80°C). Furthermore, after being immersed in a 1 M KOH solution at 80°C for 900 h, the membrane preserved 95% of its original conductivity, which is indicative of excellent alkaline stability. In AEMWE tests, it delivered a current density as high as 1.08 A cm −2 (at 2 V and 80°C), and its durability surpassed 173 h at 0.4 A cm −2 , with the voltage decay rate measured as only 0.88 mV h −1 . It demonstrates significant application potential.