A high-performance anion exchange membrane based on poly(arylene ether sulfone) with a high concentration of quaternization units

To achieve a balance between the dimensional stability and ionic conductivity coordination of anion exchange membranes (AEMs), a novel quaternized poly(arylene ether sulfone) (QPAES) with multiple phenyl units was prepared. A bis-tetraphenyl (BTP) bisphenol monomer was designed to synthesize a series of polymers through the polycondensation reaction. The as-prepared QAPES-BTP-30% showed an ion exchange capacity (IEC) of 2.46 meq g−1 and a good hydroxide conductivity (66.2 mS cm−1). The swelling behavior was also suppressed by the high-density hydrophilic groups and hydrophobic regions, thereby further improving the dimensional stability of the series of AEMs with high IECs. Small-angle X-ray scattering measurements were performed to demonstrate the distinct nanosized hydrophilic/hydrophobic phase separation. All the prepared membranes retained more than 85% of the original hydroxide conductivity and almost 90% of the IEC value after immersion in 4 M KOH aqueous solution at room temperature for 35 days. Moreover, these membranes were used for single-cell performance tests and were shown to be suitable for practical application (QAPES-BTP-30%: an open-circuit voltage (OCV) of 1.01 V and a maximum power density of 151 mW cm−2 at 60 °C under full humidification). These results suggest that QAPAES-BTP-AEMs containing concentrated quaternary ammonium show good comprehensive performance.