Homologous flexible multi-cationic cross-linkers modified poly(aryl ether sulfone) anion exchange membranes for fuel cell applications. (5th May 2022)

• Record Type: Journal Article
• Authors: Lu, Yao; Liu, Lili; Li, Na; Hu, Zhaoxia; Chen, Shouwen
• Is Part Of: International journal of hydrogen energy. Volume 47:Number 39(2022)
• Page Start: 17329
• Page End: 17340
• Publication Date: 2022-05-05
• Subjects: Poly(aryl ether sulfone) -- DABCO -- Cross-linked -- Anion exchange membrane -- Fuel cell; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2022.03.210
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Issues of unsatisfactory ionic conductivity and chemical stability should be solved for anion exchange membranes (AEMs) in practical fuel cell applications. A series of flexible spacers, homologous multi-cationic cross-linkers with different lengths, were designed and synthesized from 1, 4-diazabicyclo(2.2.2)octane (DABCO) and 1, 6-dibromohexane, and subsequently used to fabricate a series of flexible multi-cationic cross-linked poly(aryl ether sulfone) (CQPAES) AEMs. The CQPAES membranes fabricated by simultaneous cross-linking and membrane formation are tough and pliable. The length and number of cations of the cross-linkers show noticeable effects on the comprehensive membrane performance. The CQPAES membranes display more distinct nano-phase separation morphology and well-developed ion transfer channels due to the higher mobility and hydrophilicity of the flexible long-chain multi-cationic segments. As a result, the CQPAES membranes exhibit gradually increased water uptake and ionic conductivity with the increase of cross-linker length. Furthermore, DABCO and hexyl segments in the cross-linker greatly enhance the steric hindrance and electron cloud density of the quaternary ammonium groups, which inhibit the Hoffmann elimination reaction. Consequently, the CQPAES membranes display a significant improvement in alkali stability than conventional benzyl-substituted quaternary ammonium group type AEMs. Highlights: A series of flexible multi-cationic oligomers are synthesized. The cross-linked membranes exhibit a remarkable improvement in ionic conductivity. The cross-linked membranes display a well-developed ion transfer channels.