Preparation of click-driven cross-linked anion exchange membranes with low water uptake

Abstract Significant advancement in anion exchange membrane (AEM) fuel cell (AEMFC) technology is important in the field of renewable energy. AEMs with comb-shaped architectures have attracted considerable research interest because of some unique features, including high anion conductivity, low swelling, and high alkaline stability. Here, we report preparation, characterization, and performance evaluation of a novel comb-shaped cross-linked AEM synthesized by the thiol-ene click and Menshutkin reactions. The prepared ionomer decreases the trade-off between the water uptake and the conductivity. The thiol-ene click reaction was used to synthesize the 1,14-di(1H-imidazol-1-yl)-6,9-dioxa-3,12-dithiatetradecane (IDDT) cross-linker. IDDT was then introduced into the brominated poly(2,6-dimethyl-1,4-phenylene oxide) backbone by the Menshutkin reaction. The prepared ionomers show high thermomechanical stability, which is needed in AEMFC technology. The CLINK-15-100 membrane (ion exchange capacity 1.23 mmol/g) shows relatively good conductivities of 19.66 and 34.91 mS/cm at 30 and 60 °C, respectively. Interestingly, the membrane shows water uptake of only 14.22% at room temperature, which is considerably lower than many previously reported membranes. After 16 days of alkaline treatment in 1 M NaOH solution at 60 °C, the CLINK-15-100 membrane retains 77% of its initial conductivity, which is much better than the traditional quaternized poly(2,6-dimethyl-1,4-phenylene oxide) membrane.