Chemical diffusion in perovskite cathodes of solid oxide fuel cells: the Sr doped LaMn1-xMxO3 (M=Co, Fe) systems

This pager reports the results of chemical diffusion coefficient measuremen ts for oxygen in (La,Sr)(Mn,Co)O-3 and (La,Sr)(Mn,Fe)O-3 using a manometric method in the temperature range of 773 to 1023 K. It was observed that the addition of Fe or Co into (La4xSrx)(1-y)MnO3 results in a substantial incr ease of the chemical diffusion coefficient. In the range 25-100 mol% of Co or Fe substitution at B-site in (La,Sr)MnO3, the chemical diffusion coeffic ient exhibits much lower activation energy than that in (La,Sr)MnO3. The ch emical diffusion data in (La,Sr)(Mn,Co)O-3 and (La,Sr)(Mn,Fe)O-3 system det ermined by the manometric method are generally in agreement with those dete rmined by electrochemical relaxation methods reported in the literature. A comparison of the chemical diffusion data indicates that the oxygen mobilit y is lowest in (La,Sr)MnO3 and highest in (La,Sr)CoO3. (C) 2001 Elsevier Sc ience Ltd and Techna S.r.l. All rights reserved.