Long Zhi, Miyatake Kenji
Clean Energy Research Center, University of Yamanashi, Yamanashi 400-8510, Japan.
Department of Applied Chemistry, Waseda University, Tokyo 169-8555, Japan.
iScience. 2021 Aug 8;24(9):102962. doi: 10.1016/j.isci.2021.102962. eCollection 2021 Sep 24.
Sulfonated polyphenylene (SPP)-based ionomers have been developed for electrochemical applications in recent years due to their inherent thermal and chemical stability. However, the difficult synthesis, limited solubility, and rigid backbone obstructs their progress. Herein, a new monomer, 3,3″-dichloro-2',3',5',6'-tetrafluoro-1,1':4',1″-terphenyl (TP-f) with high polymerization reactivity was designed and polymerized with sulfonated phenylene monomer to prepare SPP-based ionomers (SPP-TP-f) with high ion exchange capacity up to 4.5 mequiv g. The resulting flexible membranes were more proton conductive than Nafion (state-of-the-art proton exchange membrane) even at 120°C and 20% RH. Unlike typical SPP ionomers, SPP-TP-f 5.1 was soluble in ethanol and thus, could be reinforced with double expanded polytetrafluorethylene thin layers to obtain SPP-TP-f 5.1/DPTFE membrane. SPP-TP-f 5.1/DPTFE showed superior fuel cell performance to that of Nafion, in particular, at low humidity (30% RH, > 100°C) and reasonable durability under the severe accelerated conditions combining OCV hold and humidity cycling tests.
近年来，基于磺化聚苯撑（SPP）的离聚物因其固有的热稳定性和化学稳定性而被开发用于电化学应用。然而，其合成困难、溶解度有限以及主链刚性阻碍了它们的发展。在此，设计了一种具有高聚合反应活性的新型单体3,3″-二氯-2',3',5',6'-四氟-1,1':4',1″-三联苯（TP-f），并将其与磺化苯撑单体聚合，以制备离子交换容量高达4.5 mequiv g的基于SPP的离聚物（SPP-TP-f）。所得的柔性膜即使在120°C和20%相对湿度下也比Nafion（最先进的质子交换膜）具有更高的质子传导性。与典型的SPP离聚物不同，SPP-TP-f 5.1可溶于乙醇，因此，可以用双层膨胀聚四氟乙烯薄层增强，以获得SPP-TP-f 5.1/DPTFE膜。SPP-TP-f 5.1/DPTFE在燃料电池性能方面表现优于Nafion，特别是在低湿度（30%相对湿度，>100°C）下，并且在结合开路电压保持和湿度循环测试的严苛加速条件下具有合理的耐久性。
