PHYSICAL-PROPERTIES OF MIXED CONDUCTOR SOLID OXIDE FUEL-CELL ANODES OF DOPED CEO2

Samples of CeO2 doped with oxides such as CaO and Gd2O3 were prepared. Their conductivities and expansions on reduction were measured at 100 0-degrees-C, and the thermal expansion coefficients in the range 50 to 1000-degrees-C were determined. The ionic and electronic conductivity were derived from curves of total conductivity vs. oxygen partial pre ssure. For both types of conductivity a dependence on dopant valency w as observed. The electronic conductivity was independent of dopant rad ius in contrast to the ionic which was highly dependent. These measure d physical properties are compared with the ideal requirements for sol id oxide fuel cell anodes. Not all requirements are fulfilled. Measure s to compensate for this are discussed.