Mechanical properties and electrochemical characterisation of extruded doped cerium oxide for use as an electrolyte for solid oxide fuel cells

Doped cerium oxide is a promising electrolyte for use in a medium-temperature solid oxide fuel cell (SOFC), due to its high ionic conductivity at low temperatures. A colloidal processing route has been undertaken to prepare slurries from very fine doped-cerium oxide. The dried slurry is extruded into rods and tubes and the room temperature modulus of rupture is then measured. It is shown that the material could attain a modulus in excess of 220 MPa for (CeO2)(0.8)(GdO1.5)(0.2), which is considerably greater than values obtained using traditional routes. A preliminary investigation is made of the electrochemical properties of single cells fabricated from the extruded doped-ceria tubes. At 600 degrees C, a maximum power output of approximately 38 mW cm(-2) is realised. (C) 1998 Elsevier Science S.A. All rights reserved.