Dual cross-linked polymer electrolyte membranes based on poly(aryl ether ketone) and poly(styrene-vinylimidazole-divinylbenzene) for high temperature proton exchange membrane fuel cells

• Published in: Journal of power sources Vol. 480; p. 228859
• Main Authors: Yang, Jingshuai, Jiang, Haoxing, Wang, Jin, Xu, Yixin, Pan, Chao, Li, Qingfeng, He, Ronghuan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 31-12-2020
• Subjects: Dual crosslinking; Fuel cell; High temperature electrolyte membrane; Imidazolium poly(aryl ether ketone); Dual crosslinking; High temperature electrolyte membrane; Fuel cell; Imidazolium poly(aryl ether ketone)
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2020.228859

One critical issue to phosphoric acid (PA) doped high-temperature proton exchange membranes (HT-PEMs) is to balance the proton conductivity and mechanical properties for overall application performance in fuel cells. Addressing the issue, we prepare durable HT-PEMs having the dual crosslinking structure by employing poly(vinylimidazole-divinylbenzene-styrene) (poly(VIm-DVB-St)) copolymer as a crosslinker and using the poly (aromatic ether ketone) (PAEK) polymer containing four methyl groups as the host membrane matrix. The imidazole groups of poly(VIm-DVB-St) react with benzyl bromide groups of brominated PAEK for both the primary cross-linking network and high PA doping. The divinylbenzene crosslinked poly (styrene-co-vinylimidazole) network generates the secondary cross-linking structure. The formed reticular polymer chain structure brings on low swelling and high mechanical strength of the HT-PEMs. The fuel cell based on the acid doped PAEK41-85%VIm/233.0 PA shows a H2-air fuel cell peak power density of 306 mW cm−2 at 200 °C without back pressure, and a low degradation rate of 3.9 × 10−5 V h−1 during a period of 600 h under a constant current density of 200 mA cm−2 at 160 °C.
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•Construction of dual cross-linked structure of HT-PEMs for superior properties.•High proton conductivity and mechanical strength of the prepared membranes.•The membrane-based single fuel cell (H2/air) operates stably at 160 °C for 600 h.