Side-chain-type anion exchange membranes bearing pendent imidazolium-functionalized poly(phenylene oxide) for fuel cells

A series of novel side-chain-type anion exchange membranes (AEMs) composed of poly (arylene ether sulfone)s backbone and pendent imidazolium-functionalized polyphenylene oxide (PPO) was prepared via chemical grafting, bromination, functionalization and alkalization. The chemical structure of the as-synthesized copolymers was confirmed by 1 H NMR spectroscopy . Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to observe the morphology of the AEMs. The densely functionalized side chains are found to be beneficial to the formation of ion clusters, as demonstrated by TEM. As a result, the hydroxide conductivity of the PAES-x-IMPPO membranes was 78.8   mS   cm −1 at 80   °C. Moreover, the AEMs also exhibit robust mechanical properties , good thermal stability and reasonable alkaline stability. An open circuit voltage (0.98   V) of H 2 /O 2 alkaline fuel cell using PAES-15-IMPPO at 60   °C can be an indicative of low fuel crossover. The maximum power density was 56.8   mW   cm 2 at a current density of 125   mA   cm 2 without optimization.