Journal of Power Sources, Vol.197, 20-27, 2012
Surface and interface behaviors of Sr-doped lanthanum manganite air electrode in different moisture atmospheres
Surface and interface reactions of the air electrode with the contacting components of solid oxide cells are essential for the long term operation stability and performance. In this work, an yttria-stabilized zirconia electrolyte (YSZ)/strontium-doped lanthanum manganite electrode (LSM)/AISI 441 alloy interconnect tri-layer structure has been fabricated in order to simulate the working environment of a real cell with Cr-containing interconnect. The samples are thermally treated in moist air atmospheres (0 vol%, 10 vol%, and 25 vol% moisture) at 800 degrees C for up to 500 h. The interactions among different cell components are characterized. The LSM air electrode shows slight grain growth but the growth is less in moist atmospheres. High moisture level affects the bonding between the LSM and the YSZ and leads to the formation of small particles on the YSZ surface. The amount of Cr deposition on the LSM surface is slightly more for the samples thermally treated in the moist atmospheres and shows no significant difference between the 10 vol% and 25 vol% moisture air. At the YSZ/LSM interface, La enrichment is significant and facilitates the Cr deposition while Mn depletion occurs. The YSZ surface composition is not strongly affected by the atmosphere. (C) 2011 Elsevier B.V. All rights reserved.
Keywords:Solid oxide fuel/electrolyzer cell;Air electrode;Sr-doped lanthanum manganite;Moisture;Diffusion