Preparation and evaluation of doped ceria interlayer on supported stabilized zirconia electrolyte SOFCs by wet ceramic processes

We have fabricated anode-supported solid oxide fuel cells (SOFCs) for reduced temperature operation by wet ceramic processes. Nickel/yttria-stabilised ZrO2 (Ni-YSZ), nickel/scandia-stabilised ZrO2 (Ni-ScSZ) cermets, ScSZ, gadolinia-doped ceria (GDC), and strontium-doped LaCoO3 (LSCO) were used as materials for anode substrate, anode functional layer, electrolyte, interlayer, and cathode, respectively. The influences of firing temperature of GDC films to the characteristics of ScSZ/GDC interface were investigated in detail using XRD and AC impedance spectroscopy; 1200 degreesC was considered as the optimum firing temperature of GDC film on ScSZ electrolyte. By combining the ScSZ electrolyte film with GDC interlayer, we succeeded in preventing the solid-state reactions between ScSZ and LSCO. The anode-supported SOFCs with GDC interlayer fired at 1200 degreesC generated electricity successfully at reduced temperature. However, in the case of SOFCs, with whole functional layers cofired together at 1200 degreesC, the performances of the cell were badly affected by the contact between ScSZ and GDC films. Further investigation for matching the sintering behaviors of ScSZ and GDC green films are required to realize a cost-effective cofiring process for fabricating the anode-supported SOFCs employing CGO interlayer. (C) 2004 Published by Elsevier B.V.