Preparation and characterization of quaternary ammonium functionalized poly(2,6-dimethyl-1,4-phenylene oxide) as anion exchange membrane for alkaline polymer electrolyte fuel cells

Anion exchange membrane from poly(phenylene oxide) containing pendant quaternary ammonium groups is fabricated for application in alkaline polymer electrolyte fuel cells (APEFCs). Chloromethylation of poly(phenylene oxide) (PPO) was performed by aryl substitution and then homogeneously quaternized to form an anion exchange membrane (AEM). The influence of various parameters on the chloromethylation reaction was investigated and optimized. The successful introduction of the above groups in the polymer backbone was confirmed by ¹H NMR and FT-IR spectroscopy. Membrane intrinsic properties such as ion exchange capacity, water uptake and ionic conductivity were evaluated. The membrane electrolyte exhibited an enhanced performance in comparison with the state-of-the-art commercial AHA membrane in APEFCs. A peak power density of 111 mW/cm² at a load current density of 250 mA/cm² was obtained for PPO based membrane in APEFCs at 30 °C.