Ce0.8Sm0.2O1.9（SDC）powder was prepared with an oxalate coprecipitation route.SDC solid solutions were sintered at various temperatures ranging from 1100~1450 ℃,and characterized by X-ray diffraction（XRD）,scanning electron microscopy（SEM）,density measurements,and electrical conductivity measurements.The optimized processing parameters for densification were to uniaxially press the sample at 200~400 MPa and sinter it at 1350~1400 ℃ for 4 h.The density of the sintered pellets was 〉90% of the theoretical density;their soakage was 〈0.5%;and the average grain size was 1~2 μm.The conductivities of the typical sintered specimen were 0.0133 and 0.0211 S·cm-1 at 550 and 600 ℃,respectively;Its activation energy for ionic conductivity was 0.62 eV.The dense SDC bulk material could be used as the electrolyte layer of low temperature solid oxide fuel cells.
Composites consisting of strontium stabilized bismuth oxide （Bi1.14Sr0.43O2.14, SSB） and silver were investigated as cathodes for intermediate-temperature solid oxide fuel cells with doped ceria electrolyte. There were no chemical reactions between the two components. The microstructure of the interfaces between composite cathodes and Ce0.8Sm0.2O1.9 （SDC） electrolytes was examined by scanning electron microscopy （SEM）. Impedance spectroscopy measurements show that the performance of cathode fired at 700 ℃ is the best. When the content of Ag2O is 70 wt%, polarization resistance values for the SSB-Ag cathodes are as low as 0.2 Ωcm^2 at 700℃ and 0.29 Ωcm^2 at 650℃. These results are much smaller than some of other reported composite cathodes on doped ceria electrolyte and indicate that SSB-Ag composite is a potential cathode material for intermediate temperature SOFCs.
