The role of cross-linkers in the performance of anion exchange membrane for fuel cell applications

Anion exchange membranes (AEMs) with high OH - conductivity, good alkaline stability, and dimensional stability are still challenges for AEM fuel cells to be used in practice. In this study, high-performance cross-linked AEMs are developed. To construct the hydrophilic ionic channels, a series of polysulfone-based cross-linked AEMs were prepared utilizing the DABDA cation and two distinct cross-linkers (one with ether and one without ether). The cross-linking process enhanced aggregation of ion clusters, which resulted in the formation of ion-conductive channels and phase-separated hydrophilic/hydrophobic morphology, as well as enhancing the dimensional stability of the AEMs. The produced AEMs demonstrated good conductivity relative to their swelling ratio at 70 °C, and high conductivity in the range of 19.6–46.7 mS/cm between 25 and 70 °C. Additionally, the cross-linked AEMs revealed enhanced alkaline, mechanical and thermal stability. This work presents a promising strategy for developing high-efficiency AEMs for fuel cells.