Enhancing the Chemical Stability of Poly(isatin terphenyl)-Based Anion Exchange Membranes by Cross-Linking with Quaternary Ammonium-Functionalized Noria

Anion exchange membranes (AEMs) with superior conductivity and excellent chemical stability are always desired. Herein, tertiary amine-functionalized Noria (FNoria) is synthesized for use as both a cross-linker and free radical scavenger to fabricate AEMs based on quaternized poly(isatin 1-bromo-3,5-diphenylbenzene-co-terphenyl) (QPIBT). The macrocyclic FNoria endows the membranes with suitable microphase separation according to the relevant morphology analysis. An ionic conductivity as high as 115 mS cm^–1 is achieved at 80 °C in water by the FNoria-containing membrane. The presence of the FNoria results in a conductivity retention rate ranging within 80–86% after immersing the membranes in 2 mol L^–1 KOH aqueous solutions at 80 °C for 1200 h. The membrane-based single fuel cell achieves a peak power density of 1.08 W cm^–2 at 80 °C by feeding with humidified H₂ and O₂ under a back pressure of 0.05 MPa. The single fuel cell could retain 77% of its original voltage after operating under a current density of 200 mA cm^–2 at 60 °C for 91 h. Fuel cell tests demonstrate the use possibility of the proposed membrane electrolyte.