Anion exchange membrane crosslinked in the easiest way stands out for fuel cells

Covalent crosslinking is an effective method to stabilize anion exchange membranes (AEMs) against water swelling and high alkaline environment, yet complicated process is required. We report herein a straightforward approach to prepare highly crosslinked, transparent and flexible AEM by simply immersing a halo-alkylated polymer (e.g., brominated poly-(2,6-dimethyl-phenylene oxide)) based membrane in aqueous dimethylamine solution at room temperature and the following methylation. During this crosslinking process, a robust self-crosslinking network is formed which shows a gel fraction in N-methyl-2-pyrrolidone of (up to) 94%. Self-crosslinked membranes show low water uptakes (20-42%) and dimensional swelling (9-16%) compared to non-crosslinked membrane but good hydroxide conductivities (up to 26 mS cm(-1)) at room temperature. Besides, the resulting membranes show some interesting features: the membranes do not immensely change its room temperature water swelling properties at high temperature but exhibits good hydroxide conductivities (up to 60 mS cm(-1) at 80 degrees C). Noting that, the self-crosslinked AEM reported here has no beta-hydrogens, exhibiting extremely high alkaline stability (no decline in hydroxide conductivity in 1 M KOH at 60 degrees C for 360h). Membrane electrode assembly consists of fabricated membrane shows moderate fuel cell performance reaching peak power density 31 mW cm(-2) at 60 degrees C in a H-2/O-2 alkaline fuel cell.