Enhanced Proton Conductivity of Sulfonated Hybrid Poly(arylene ether ketone) Membranes by Incorporating an Amino–Sulfo Bifunctionalized Metal–Organic Framework for Direct Methanol Fuel Cells

• Published in: ACS applied materials & interfaces Vol. 10; no. 9; pp. 7963 - 7973
• Main Authors: Ru, Chunyu, Li, Zhenhua, Zhao, Chengji, Duan, Yuting, Zhuang, Zhuang, Bu, Fanzhe, Na, Hui
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 07.03.2018
• Subjects: coordination polymers; crosslinking; electric power; electrochemistry; fluorine; fuel cells; methanol; microstructure; moieties; naphthalene; protons; strength (mechanics); direct methanol fuel cells; proton conductivity; sulfonated poly(arylene ether ketone); bifunctionalized metal−organic framework; polymer electrolyte membranes
• ISSN: 1944-8244; 1944-8252; 1944-8252
• DOI: 10.1021/acsami.7b17299

Novel side-chain-type sulfonated poly­(arylene ether ketone) (SNF-PAEK) containing naphthalene and fluorine moieties on the main chain was prepared in this work, and a new amino–sulfo-bifunctionalized metal–organic framework (MNS, short for MIL-101-NH2-SO3H) was synthesized via a hydrothermal technology and postmodification. Then, MNS was incorporated into a SNF-PAEK matrix as an inorganic nanofiller to prepare a series of organic–inorganic hybrid membranes (MNS@SNF-PAEK-XX). The mechanical property, methanol resistance, electrochemistry, and other properties of MNS@SNF-PAEK-XX hybrid membranes were characterized in detail. We found that the mechanical strength and methanol resistances of these hybrid membranes were improved by the formation of an ionic cross-linking structure between −NH2 of MNS and −SO3H on the side chain of SNF-PAEK. Particularly, the proton conductivity of these hybrid membranes increased obviously after the addition of MNS. MNS@SNF-PAEK-3% exhibited the proton conductivity of 0.192 S·cm–1, which was much higher than those of the pristine membrane (0.145 S·cm–1) and recast Nafion (0.134 S·cm–1) at 80 °C. This result indicated that bifunctionalized MNS rearranged the microstructure of hybrid membranes, which could accelerate the transfer of protons. The hybrid membrane (MNS@SNF-PAEK-3%) showed a better direct methanol fuel cell performance with a higher peak power density of 125.7 mW/cm2 at 80 °C and a higher open-circuit voltage (0.839 V) than the pristine membrane.