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Migration and Precipitation of Platinum in Anion-Exchange Membrane Fuel Cells |
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| Authors: | Aniket Raut Haoyan Fang Yu-Chung Lin Shi Fu David Sprouster Ryuichi Shimogawa Anatoly I. Frenkel Chulsung Bae John C. Douglin Jaana Lillojad Kaido Tammeveski Zhiqiao Zeng Stoyan Bliznakov Miriam Rafailovich Dario R. Dekel |
| Affiliation: | 1. Department of Materials Science and Chemical Engineering, State University of New York at Stony Brook, Stony Brook, NY, 11794 USA;2. Department of Materials Science and Chemical Engineering, State University of New York at Stony Brook, Stony Brook, NY, 11794 USA Mitsubishi Chemical Corporation, Science & Innovation Center, 1000, Kamoshida-cho, Aoba-ku, Yokohama 227–8502 Japan;3. Department of Materials Science and Chemical Engineering, State University of New York at Stony Brook, Stony Brook, NY, 11794 USA Division of Chemistry, Brookhaven National Laboratory, Upton, NY, 11973 USA;4. Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY, 12180 USA;5. The Wolfson Department of Chemical Engineering, Technion—Israel Institute of Technology Haifa 3200003 (Israel);6. Institute of Chemistry, University of Tartu, Ravila 14a, 50411 Tartu, Estonia;7. Center for Clean Energy Engineering, University of Connecticut, Storrs, CT, 06269 USA;8. The Wolfson Department of Chemical Engineering, Technion—Israel Institute of Technology Haifa 3200003 (Israel) The Nancy & Stephen Grand Technion Energy Program (GTEP), Technion—Israel Institute of Technology, Haifa, 3200003 Israel |
| Abstract: | Despite the recent progress in increasing the power generation of Anion-exchange membrane fuel cells (AEMFCs), their durability is still far lower than that of Proton exchange membrane fuel cells (PEMFCs). Using the complementary techniques of X-ray micro-computed tomography (CT), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) spectroscopy, we have identified Pt ion migration as an important factor to explain the decay in performance of AEMFCs. In alkaline media Pt+2 ions are easily formed which then either undergo dissolution into the carbon support or migrate to the membrane. In contrast to PEMFCs, where hydrogen cross over reduces the ions forming a vertical “Pt line” within the membrane, the ions in the AEM are trapped by charged groups within the membrane, leading to disintegration of the membrane and failure. Diffusion of the metal components is still observed when the Pt/C of the cathode is substituted with a FeCo−N−C catalyst, but in this case the Fe and Co ions are not trapped within the membrane, but rather migrate into the anode, thereby increasing the stability of the membrane. |
| Keywords: | Electrochemistry FeCo Migration Fuel Cells Platinum Stability Testing |