Thermally Cross-Linked Polybenzimidazole Membranes with a Di-Azide Cross-Linker for High-Temperature Proton Exchange Membrane Fuel Cells
발표자
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초록
내용
Cross-linked poly(4,4′-(diphenyl ether)-5,5′-bibenzimidazole) (OPBI) membranes are prepared through an in-situ casting method with ethynyl-grafted OPBI as the base material and 4,4′-diazido-2,2′-stilbenedisulfonic acid disodium salt tetrahydrate (DSDAD) as the cross-linker. Cross-linking occurs via azide-alkyne click chemistry and dimerization of ethynyl groups, resulting in membranes with improved oxidative stability and mechanical strength compared to linear OPBI membranes. Furthermore, these membranes exhibit higher proton conductivity, owing to DSDAD's ability to form multiple hydrogen bonds within the polymer matrix and create triazole linkages through the cross-linking process. The optimized C_E-OPBI-2 membrane, with an ideal degree of cross-linking, achieves a 27% higher power density than the unmodified OPBI membrane due to these enhancements.