Multi-block poly(ether sulfone) for anion exchange membranes with long side chains densely terminated by piperidinium

To meet highly conductive and chemical stable anion exchange membranes (AEMs), a series of multi-block poly(ether sulfone)s with long side chains densely terminated by piperidinium (bPES-Pip-X-Y) are synthesized. The multi-block structure and the aggregation of ionic groups on the flexible side chains are responsible for the distinct hydrophilic/hydrophobic microphase separation, which can be observed via transmission electron microscopy (TEM). The resulted membranes achieve the high conductivity (in-plane) of 48.5–105.4 mS cm−1 at 80 °C. Moreover, the AEMs prepared exhibit good alkaline stability due to the presence of cation-terminated long side chain structure. The bPES-Pip-10-5 membrane still maintains 88% of the original conductivity after treated in 1 M KOH solution at 60 °C for 336 h. The membrane electrode assembly based on bPES-Pip-10-5 with a power density of 136.9 mW cm−2 at a current density of 292.5 mA cm−2 is obtained.