Deposition of Cr species at (La,Sr)(Co,Fe)O3 cathodes of solid oxide fuel cells

Deposition process of Cr species at the (La, Sr) (Co, Fe)O-3 (LSCF) electrode and Gd0.2Ce0.8O2 (GDC) electrolyte system is investigated under the O-2 reduction conditions in the presence of a Fe-Cr alloy interconnect for solid oxide fuel cells. Deposition of Cr species preferentially occurs on the surface of the LSCF electrode with and without the cathodic polarization at 900 degrees C, forming SrCrO4 and Cr2O3 phase. At the initial stage of the reaction, Cr deposition was not detected inside the LSCF electrode or at the LSCF electrode/GDC electrolyte interface. Deposition of Cr species on the LSCF electrode surface under the rib of Fe-Cr alloy interconnect is substantial in comparison to that under the channel of the interconnect. The results demonstrate clearly that the deposition of Cr species at the LSCF electrode is essentially a chemical reaction and is kinetically controlled by nucleation reaction between the gaseous Cr species and SrO-enriched/segregated on the LSCF electrode surface. (c) 2005 The Electrochemical Society.