Performance of a La 0.6Sr 0.4Co 0.8Fe 0.2O 3–Ce 0.8Gd 0.2O 1.9–Ag cathode for ceria electrolyte SOFCs

• Published in: Solid state ionics Vol. 146; no. 3; pp. 203 - 210
• Main Authors: Wang, Shaorong, Kato, Tohru, Nagata, Susumu, Honda, Takeo, Kaneko, Toshimi, Iwashita, Nobuharu, Dokiya, Masayuki
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 2002
• Subjects: Cathode; Ceria; Lanthanum cobaltite; Low temperature SOFC; Silver; Silver; Cathode; Ceria; Low temperature SOFC; Lanthanum cobaltite
• ISSN: 0167-2738; 1872-7689
• DOI: 10.1016/S0167-2738(01)01015-3

Performance of an La 0.6Sr 0.4Co 0.8Fe 0.2O 3–CGO–Ag cathode (where CGO is Ce 0.8Gd 0.2O 1.9) on a Ce 0.8Sm 0.2O 1.9 electrolyte was studied by the three-probe AC impedance method at the steady state of various DC bias currents. The electrode consisted of a porous layer of La 0.6Sr 0.4Co 0.8Fe 0.2O 3–CGO (30 wt.%) and a layer of Ag particles coated on the surface. The Ag coating was used to improve the oxygen exchange reaction activity. As a result, an interface conductivity greater than 1 S/cm 2 was obtained at 600 °C with a low activation energy. The dependence of the AC impedance on the frequency was analyzed in order to clarify the reaction steps in the oxygen reduction mechanism.