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Author

Kim, Guntae
GUNS Lab
Research Interests
  • Solid Oxide Fuel Cells (SOFCs)& SOE, metal-air batteries, ceramic membranes, PEMFC

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Activation and Ripening of Impregnated Manganese Containing Perovskite SOFC Electrodes under Redox Cycling

Cited 29 times inthomson ciCited 23 times inthomson ci
Title
Activation and Ripening of Impregnated Manganese Containing Perovskite SOFC Electrodes under Redox Cycling
Author
Corre, G.Kim, GuntaeCassidy, M.Vohs, J. M.Gorte, R. J.Irvine, J. T. S.
Keywords
Chemical interactions; Electro-chemical reactions; Electrode microstructures; Favorable interactions; Interconnected arrays; Microfissures; Microstructure changes; Mn concentrations; Nano-scale particles; Precursor solutions; Re oxidations; Redox cycling; Smooth coatings; Thin coatings; Triple phase boundaries; Yttria-stabilized zirconias
Issue Date
200903
Publisher
AMER CHEMICAL SOC
Citation
CHEMISTRY OF MATERIALS, v.21, no.6, pp.1077 - 1084
Abstract
The impregnation of electrode precursor solutions is a very powerful technique for creating novel electrode microstructures constrained within preformed scaffolds. Here we report on the microstructural evolution of Mn-containing perovskites impregnated into yttria stabilized zirconia scaffolds on heating and redox cycling. Good performances have previously been reported for SOFC anodes with similar structure, and our objective is to better understand the origins of this good performance. For La(0.75)Sr(0.25)Cr(0.5)Mn(0.5)O(3-delta) a remarkable thin coating with microfissures is formed on the scaffold after firing the electrode precursors at 1200 degrees C, and such behavior can be considered as wetting of one oxide by another. On further treating this microstructure at 800 degrees C in H(2) the microstructure changes dramatically forming an interconnected array of similar to 10 nm scale particles. This seems to offer a very attractive structure with extensive triple phase boundary regions where electrochemical reactions can occur. On reoxidation at this temperature the particles reagglomerate to form a structure approaching the initial smooth coating. Performing similar procedures on the system La(0.33)Sr(0.67)Ti(x)Mn(1-)xO(3 +/-delta) we find that the wetting only occurs if Mn is present in the oxide and that the degree of wetting increases with Mn concentration. This favorable interaction between the Mn containing perovskites and the zirconia scaffold must be associated with a chemical interaction between impregnated oxide and substrate. The strength of this interaction decreases on reduction allowing the perovskite electrode to form nanoscale particles which along with appropriate additional catalysts provide good electrode functionality.
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DOI
http://dx.doi.org/10.1021/cm803149v
ISSN
0897-4756
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