Evaluation of the La0.75Sr0.25Mn0.8Co0.2O3−δ system as cathode material for ITSOFCs with La9Sr1Si6O26.5 apatite as electrolyte

• Published in: Journal of the European Ceramic Society Vol. 29; no. 9; pp. 1781 - 1788
• Main Authors: Bonhomme, Claire, Beaudet-Savignat, Sophie, Chartier, Thierry, Geffroy, Pierre-Marie, Sauvet, Anne-Laure
• Format: Journal Article
• Language: English
• Published: 01.06.2009
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2008.11.009

Major interest has been devoted to decrease the working temperature of solid oxide fuel cells (SOFCs) down to about 700 C. Apatite materials (La10-xSrxSi6O27-x/2) are attractive candidates for solid electrolytes, with a high ionic conductivity at 700 C, a chemical and a dimensional stability for a pO2 ranging from 10 exp(-25) to 0.2 atm. A perovskite oxide (La0.75Sr0.25Mn0.8Co0.2O3-delta) has been used as a cathode material. Symmetrical cathode/electrolyte/cathode cells were fabricated by stacking layers of apatite and perovskite powders obtained by tape casting and co-sintering at 1400 C for 2 h in air. Impedance spectroscopy measurements were performed on these cells in order to determine the electrode resistance. The latter decreased with the porosity content of the cathode and with the use of a composite material (apatite/perovskite) instead of a simple perovskite.