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Suppression of Chromium Poisoning in SOFC Cathode Using Chromium Trapping Materials

Wednesday, 26 July 2017: 11:00
Grand Ballroom West (The Diplomat Beach Resort)
J. H. Lee (Korea Institute of Science and Technology (KIST)), H. Kim (KIST), K. J. Yoon (Korea Institute of Science and Technology (KIST)), M. Park (KIST), H. Kim, J. W. Son, B. K. Kim, and H. W. Lee (Korea Institute of Science and Technology (KIST))
Solid oxide fuel cells (SOFCs) represent one of the most environmentally friendly and versatile technologies for generation of electrical power and heat from a variety of fuels through electrochemical reactions. Currently, one of the major challenges for commercialization of SOFC technology is the lack of long-term reliability at high temperatures. Especially the high-temperature degradation of SOFC materials with respect to contaminants, structural degradation and material decomposition is known to be the main cause of poor reliability of SOFCs which makes significantly mitigating a broad implementation of SOFCs. Thus, a fundamental understanding of the degradation mechanisms of SOFC materials is needed to find the best degradation mitigation strategies and apply them in order to advance the commercialization of SOFCs.

Among many sources of degradation of solid oxide fuel cells (SOFCs), chromium poisoning of cathode has been one of the major concerns for commercial development and deployment. Chromium evaporates from the metallic components of the stack and system in oxidizing atmosphere, and deposits on the active sites of the cathode, leading to degradation of electrode performance. One of the most general approaches to suppress chromium poisoning is to cover the metallic components with protective coating, and various coating materials and deposition techniques have been proposed. However, it is difficult to form sufficiently dense and stable coating on entire part of the potential chromium source of the system. Therefore, solely relying on protective coating for suppression of chromium poisoning is not considered to be reliable, and it is desirable to have additional means to further block chromium vapor from reaching cathode.

In this presentation, effect of chromium poisoning on cathode reaction was studied using impedance spectroscopy to illuminate the degradation process in SOFC cathode. From this investigation, especially focused on the air side of SOFCs which occupies the largest portion of SOFC deterioration, we want to identify the underlying degradation mechanisms and propose possible mitigation strategies based on our experimental results.

See more of: SOFC Cathodes IV
See more of: I01: Fifteenth International Symposium on Solid Oxide Fuel Cells
See more of: Fuel Cells, Electrolyzers, and Energy Conversion
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