“Windmill” shaped branched anion-conducting poly(aryl piperidine) with extra molecular interaction sites as new anion exchange membranes

In order to optimize the ion transport capacity and chemical stability, precisely control over the polyelectrolyte structure, and the "windmill" shaped branched poly(aryl piperidine) basic membrane is designed and prepared. Considering the consecutive hydrophobic microphase will unavoidably be a barrier to the ion transport between dispersed hydrophilic ion clusters, the introduction of pendant cyclic ammonium and polar 2-(2-chloroethoxy)ethanol within the membrane can generate highly ordered interconnected ion network domains, supplying a three-dimensional path for ion and water transport. In addition, the presence of terminal hydroxyl groups in polar chain segments enables AEMs to obtain dynamic non-covalent crosslinking effects without additional crosslinking agents, improving the toughness of the membrane, which can be used to fabricate ultrathin self-supported membranes with reduced ohmic resistance. The membrane (TPTP-Pip–OH–20%) exhibits high hydroxide conductivity (143.2 mS cm−1 at 80 °C) and maintains conductivity (87.4% retention for more than 60 days) after testing in 2 M NaOH at 80 °C, showing highly alkaline stability. Besides, the single H2–O2 fuel cell based on TPTP-Pip–OH–20% exhibits a peak power density of 405 mW cm−2 at 80 °C. The novel structural design presents promising solutions for high-performance polyelectrolyte conductive membrane materials, which will benefit many fields involving anion-conducting electrolytes.