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Nafion
About: Nafion is a research topic. Over the lifetime, 9110 publications have been published within this topic receiving 320865 citations.
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TL;DR: In this article, the ionic and water transport characteristics of Nafion ionomer membranes were investigated systematically in the mixed cation form of H+ and various kinds of alkali metal cation systems, which were prepared by equilibrating the membranes in the mixtures of HCl and alkali chloride in aqueous solutions of various mixing ratios.
Abstract: Ion and water transport characteristics of Nafion ionomer membranes were investigated systematically in the mixed cation form of H+ and various kinds of alkali metal cation systems, which were prepared by equilibrating the membranes in the mixtures of HCl and alkali chloride in aqueous solutions of various mixing ratios. The membrane cationic composition showed that cations of larger atomic number had a higher affinity to sulfonic acid groups but less water content in the membrane than those of smaller atomic numbers. The net ionic conductivity was decreased, in any case, by the presence of alkali metal cations in the membrane. Different kinds of the interaction mode among cations were observed between H/Li or H/Na systems and H/K, H/Rb, or H/Cs systems. The interaction between alkali metal cations appeared to increase as the atomic number of the alkali metal cation increased. The water transference coefficient (electro-osmosis drag coefficient) increased from 2.5 to more than 10 by the presence of alkali...
177 citations
TL;DR: The studies support the proposal that long-range proton charge transfer in [Nafion/(SiO2)x] composites takes place due to a mechanism involving exchange of the proton between the four water domains.
Abstract: This report describes a study of the effect of SiO2 nanopowders on the mechanism of ionic motion and interactions taking place in hybrid inorganic−organic membranes based on Nafion. Five nanocompos...
177 citations
TL;DR: In this paper, the effects of ionomer content on the proton exchange membrane fuel cell (PEMFC) performance of membrane electrode assemblies (MEAs) fabricated by a catalyst-coated membrane spraying method in partially humidified atmospheric air and hydrogen.
177 citations
TL;DR: Aryl ether-free poly(fluorene) ionomer was used in this article to minimize undesirable phenyl group interaction with hydrogen oxidation catalysts and achieved a peak power density of 146 W cm−2, approaching that of Nafion-based PEMFCs.
Abstract: Alkaline membrane fuel cells (AMFCs) show great potential as alternative energy conversion devices to acidic proton exchange membrane fuel cells (PEMFCs) Over the last decade, there has been significant progress in the development of alkaline-stable polyaromatic materials for membrane separators and ionomeric binders for AMFCs However, the AMFC performance using polyaromatic ionomers is generally poor, ca a peak power density of <400 mW cm−2 Here, we report a rational design for polyaromatic ionomers which can minimize undesirable phenyl group interaction with hydrogen oxidation catalysts The AMFC using a newly designed aryl ether-free poly(fluorene) ionomer exhibits a peak power density of 146 W cm−2, which is approaching that of Nafion-based PEMFCs This study further discusses the remaining challenges of high-performing AMFCs
176 citations
TL;DR: In this article, a new set of force field functions and parameters are proposed on the basis of the DFT calculations on molecular fragments composing the interfacial materials, and detailed free energy analysis indicated the presence of two distinctive barriers limiting the O 2 permeation flux at the gas/Nafion interface and Nafion/Pt interface.
176 citations