Preparation and characterization of crosslinked anion exchange membrane (AEM) materials with poly(phenylene ether)-based short hydrophilic block for use in electrochemical applications

Herein, our group report the investigation of cross-linked copolymer anion exchange membrane (AEM) materials with a partially rigid backbone structure based on poly(phenylene ether). Two types of quaternized AEM materials, QCPPAE-2/1 and QCPPAE-4/1, with an ion exchange capacity (IEC) of 1.08 and 1.75 meq/g, respectively, were synthesized. The cross-linked AEMs exhibited a low water uptake (WU) and dimensional change and outstanding anion (Cl-, SO42-, and OH-) conductivities. The nanoscale phase-separated morphologies of the polymer membranes were characterized using small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM). The synthesized membranes were introduced as a solid electrolyte into a vanadium redox flow battery (VRFB) and an anion exchange membrane fuel cell (AEMFC). The QCPPAE-2/1 membrane showed excellent coulombic efficiency (CE) of 99%, voltage efficiency (VE) of 88% and energy efficiency (EE) of 89% in VRFBs. Within AEMFCs, these membranes generated an outstanding power density as high as 106 mW/cm(2) at 60 degrees C.