Highly conductive anion exchange membranes with long flexible multication spacer

Poly(ether ketone)s bearing multication side chains are synthesized via nucleophilic polycondensation , demethylation and the Williamson reaction to prepare high performance anion exchange membranes (AEMs). The introduction of multication side chains is found to promote the formation of hydrophilic/hydrophobic phase segregated morphology, as confirmed by transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The TQAPEK-0.5 membrane with ionic exchange capacity (IEC) of 1.94 meq g −1 shows the highest hydroxide conductivity of 132.8 mS cm −1 at 80 °C. The first cationic group on the side chain is linked to the backbone via hexyleneoxy groups to render the AEM a good alkaline stability. As a result, TQAPEK-0.5 has only a 22.4% decrease in the conductivity after immersed in a 2 M aqueous KOH solution at 60 °C for 600 h. Besides, the peak power density of a single cell using the TQAPEK-0.5 membrane is observed to be 206 mW cm −2 at a current density of 400 mA cm −2 . Furthermore, the as-prepared AEMs also exhibit good mechanical property and thermal stability, and hold promise for application in fuel cells.