MTE Graduate student Seminar Series
Chromium Impurity Effects in Solid Oxide Fuel Cell Cathodes: The Role of Thermodynamics and Transport
Chromium is a ubiquitous impurity species present in the cathode atmosphere of solid oxide fuel cells (SOFCs) arising from contact with ferritic stainless steel interconnections, and from balance of plant components. When it is present in the gas phase, it is transported as a vapor phase oxide and oxy-hydroxide species through the pore phase in the cathode to the electrochemically active regions and leads to poisoning of the cathode. However, the response of the cathode to chromium exhibits a markedly different behavior when the cathode comprises of a predominantly electron-hole conductor such as strontium-doped lanthanum manganite (LSM) than when it comprises of a mixed ionic and electron-hole conductor such as strontium-doped lanthanum cobalt iron oxide (LSCF) or lanthanum nickelate (LNO). In this talk we analyze the various deconvoluted polarization losses and their time evolution in the presence of chromium impurity species, and the role of electronic and ionic transport in chromium poisoning which has implications for the long term cell performance degradation.