Towards performance improved anion exchange membrane: Cross-linking with multi-cations oligomer modified graphene oxide

Cross-linking structure has been proven to be an effective approach to address the balance issue between ionic conductivity, dimensional stability and other properties of anion exchange membranes (AEMs). Here, a novel multi-cationic oligomer was synthesized from 1,4-diazabicyclo [2,2,2]octane and 1,6-dibromohexane, and subsequently used to prepare multi-cationic oligomer brushes-decorated graphene oxide (QBGO). The obtained QBGO was employed as the cross-linker to form cross-linked poly (arylene ether sulfone) (QPAES) AEMs by end-cap tertiary amine coupling reaction. Benefiting from the introduction of the multi-cations and flexible long-chain cross-linker structure, the cross-linked QPAES/QBGO membranes formed hydrophilic/hydrophobic phase-separation microstructures and welldefined ionic channels which are responsible for water uptake and ion transfer. As a result, the cross-linked QPAES/QBGO-2.0 membrane exhibited 1.90-fold higher ionic conductivity and better chemical stability than the control QPAES membrane. The QPAES/QBGO-2.0 membrane displayed a higher power density of 75.7 mW cm -2 than that of the control QPAES membrane (53.1 mW cm(-2)) in a H-2/O-2 fuel cell test. In a word, we propose that this novel design strategy holds broad prospects for the design of new polymer electrolyte membrane materials . (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this study, a novel multi-cationic oligomer was used as a cross-linker to prepare cross-linked QPAES/QBGO membranes with well-defined ionic channels and phase separation characteristics. The cross-linked membrane showed improved ionic conductivity, chemical stability, and power density compared to the control membrane. This novel design strategy holds broad prospects for the development of new polymer electrolyte membrane materials.