Highly Ion-Conductive and Alkaline Stable Anion Exchange Membranes Containing Bulky Aryl Units and Symmetric bis-Piperidinium Branches

Abstract

The challenge in developing high-performance anion exchange membranes (AEMs) involves achieving high ion conductivity while maintaining sufficient alkaline and mechanical stability. In this work, an aromatic monomer [bis(4′-(1,5-dibromopentan-3-yl)phenyl)-1,4-terphenyl (BBTP)] with a bulky aryl unit and symmetric dibrominated branches was first designed and synthesized. Then, BBTP was used to prepare aryl ether-free AEMs (QPTPDP-x-OH) via the superacid-catalyzed polyhydroxyalkylation and Menshutkin reactions. Due to the several structural advantages of BBTP, QPTPDP-x-OH membranes reached high hydroxide conductivity up to 161.5 mS cm–1 at 80 °C while maintaining good dimensional stability. Moreover, the membranes exhibited high alkaline stability with the conductivity retention above 80% after soaking in 5 M NaOH at 80 °C for 1200 h. In addition, QPTPDP-30-OH membranes achieved a peak power density of 407.8 mW cm–2 in H2–O2 fuel cells at 60 °C. The design strategy used in this work provided insights into the development of next-generation AEMs with high performance.

Enhanced Performance and Stability of Poly(carbazole)-Based Anion Exchange Membranes via Synergistic Dual Side Chains for Fuel Cell Applications

“…Therefore, obtaining higher ionic conductivity with a smaller IEC is becoming more attractive in the AEM research fields. The function of the IEC and the ionic conductivity of the AEM Q-BOC-OEC-1/1 are compared with the literatures, as shown in Figure b. ,,,,,,,,,,,− The AEM prepared in this study demonstrated higher ionic conductivity and compared other AEMs with similar IEC due to the effect of their synergistic dual functional side chains, in addition, some poly­(arylene-alkylene)-based AEMs demonstrated high performance similar to Q-BOC-OEC-1/1 attributed to the distinct phase separation between the hydrophobic main chain and the hydrophilic side chain. − As one kind of poly­(arylene-alkylene)-based AEMs, the membrane Q-BOC-OEC-1/1 in this work chooses carbazole as the aryl group, which still has the same advantages in terms of morphology construction-induced ion transport.…”

Crosslinked high-performance anion exchange membranes based on poly(dibenzyl N-methyl piperidine) and pentafluorobenzoyl-substituted SEBS

“…20,36,37 Polyarylene-based AEMs, characterized by a rigid structure, exhibit a WU ≤ 100% and an SR ≤ 20%. 43–49 Regarding the x -PDB- m -F5-SEBS membranes, the WU ranges from 90.7–111.1%, with an SR of 25.0–30.2%, values falling between the SEBS- and polyarylene-based AEMs. Hence, excessive membrane expansion typically associated with SEBS is effectively suppressed and enhanced dimensional stability is achieved.…”