Fabrication and properties of Ce0.8Gd0.2O1.9 electrolyte-based tubular solid oxide fuel cells

A general procedure for the extrusion of Ce0.8Gd0.2O1.9 tubular electrolyte s is detailed. Using a commercial water-based binder system, Ce0.8Gd0.2O1.9 was extruded, then fired at 1600 degrees C to form high-density electrolyt e tubes (98% relative to theoretical). Heat-treatment of the Ce0.8Gd0.2O1.9 powder at 900 degrees C for 4 h yielded tubes that were highly dense with a smooth surface finish, while non heat-treated powders resulted in an extr usion that was less dense with poor surface finish. Electrodes were applied and the tubular SOFC was electrically tested. A good open circuit voltage of 0.911 V was achieved for the cell, however a poor operating current dens ity of 0.0123 A/cm(2) at 0.7 V was obtained. The results demonstrate the po tential of fabricating and operating tubular SOFCs. (C) 1999 Elsevier Scien ce B.V. All rights reserved.