Optimum cathode configuration for IT-SOFC using La0.4Ba0.6CoO3−δ and Ce0.9Gd0.1O1.95

Three different cathode configurations using porous layers of La0.4Ba0.6CoO3−δ (LBC), LBC–GDC composite in a 50:50 weight ratio, and GDC were prepared and measured by impedance spectroscopy on symmetrical cells. These three cathode configurations were: A) porous GDC + LBC, B) porous GDC + LBC−GDC composite, and C) porous GDC + LBC–GDC composite + LBC. The minimum polarization resistance (Rp) value was obtained with configuration C. The incorporation of both the porous GDC layer and the intermediate layer of LBC–GDC composite, allowed us to solve adherence problems caused by the total expansion mismatch between LBC (26·10−6 K−1) and GDC (12·10−6 K−1). The Rp values obtained with cell C are comparable to the performance of another cell C prepared with Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF). For example, the Rp values at 600 °C, in air, were 0.071 and 0.065 Ωcm2 for LBC and BSCF, respectively. These results suggest that configuration C is very promising for developing IT-SOFC cathode with low Rp values.