Enhanced Chromium Tolerance of Gd_0.1Ce_0.9O_1.95 Impregnated La_0.6Sr_0.4Co_0.2Fe_0.8O_{3-δ Electrode of Solid Oxide Fuel Cells}

Abstract

The electrochemical activities and chromium tolerances are studied on pure La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) and Gd 0.1 Ce 0.9 O 1.95 (GDC) impregnated LSCF (GDC-LSCF) electrodes of solid oxide fuel cells. Using electrochemical impedance spectroscopy (EIS) technology, a significant reduction in the electrode polarization resistance (R E ) for O 2 reduction particularly at low temperatures is obtained after GDC impregnated. Form the analysis results of EIS, the low frequency resistances are markedly reduced due to a positive effect of GDC coating on oxygen dissociative adsorption process. Most importantly, the overpotential (η) of GDC-LSCF electrode at 800 °C for 40 h in the presence of Fe-Cr metallic interconnect presents more stable than that of pure LSCF electrode, implying an enhanced Cr tolerance after GDC introduced. Moreover, SEM-EDS results indicate that Cr deposition is selective and occurs preferentially on LSCF surface rather than GDC, suggesting that GDC impregnation is a promising technique for the development of Cr-tolerance electrode in SOFCs.