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

The challenge in developing high-performance anion exchangemembranes(AEMs) involves achieving high ion conductivity while maintainingsufficient alkaline and mechanical stability. In this work, an aromaticmonomer [bis-(4 '-(1,5-dibromopentan-3-yl)-phenyl)-1,4-terphenyl(BBTP)] with a bulky aryl unit and symmetric dibrominated brancheswas first designed and synthesized. Then, BBTP was used to preparearyl ether-free AEMs (QPTPDP-x-OH) via the superacid-catalyzedpolyhydroxyalkylation and Menshutkin reactions. Due to the severalstructural advantages of BBTP, QPTPDP-x-OH membranesreached high hydroxide conductivity up to 161.5 mS cm(-1) at 80 degrees C while maintaining good dimensional stability. Moreover,the membranes exhibited high alkaline stability with the conductivityretention above 80% after soaking in 5 M NaOH at 80 degrees C for 1200h. In addition, QPTPDP-30-OH membranes achieved a peak power densityof 407.8 mW cm(-2) in H-2-O-2 fuel cells at 60 degrees C. The design strategy used in this workprovided insights into the development of next-generation AEMs withhigh performance.