Performance stability and degradation mechanism of La₀.₆Sr₀.₄Co₀.₂Fe₀.₈O₃₋δ cathodes under solid oxide fuel cells operation conditions
By Liu, Yihui; Chen, Kongfa; Zhao, Ling; Chi, Bo; Pu, Jian; Jiang, San Ping & Jian, Li
Published in International Journal of Hydrogen Energy
2014
Abstract
The performance stability and degradation mechanism of La₀.₆Sr₀.₄Co₀.₂Fe₀.₈O₃₋δ (LSCF) cathodes and LSCF impregnated Gd0.1Ce₀.₉O₂₋δ (LSCF-GDC) cathodes are investigated under solid oxide fuel cell operation conditions. LSCF and LSCF-GDC cathodes show initially performance improvement but degrade under cathodic polarization treatment at 750 °C for 120 h. The results confirm the grain growth and agglomeration of LSCF and in particular GDC-LSCF cathodes as well as the formation of SrCoOᵪ particles on the surface of LSCF under cathodic polarization conditions. The direct observation of SrCoOᵪ formation has been made possible on the surface of dense LSCF electrode plate on GDC electrolyte. The formation of SrCoOᵪ is most likely due to the interaction between the segregated Sr and Co from LSCF lattice under polarization conditions. The formation of SrCoOᵪ would contribute to the deterioration of the electrocatalytic activity of the LSCF-based electrodes for the O₂ reduction in addition to the agglomeration and microstructure coarsening.