Synthesis And Electrical Conductivity Of SrCe_1-xYb_xO_3-αCeramic

Proton-conducting SrCe_1-xHo_xO_3-α(x=0.05,0.1,0.15,0.2) ceramic was prepared by high-temperature solid-state reaction and sol-gel reaction. X-ray powder diffraction pattern shows that the ceramic is of a single orthorhombic phase of perovskite-type SrCeO₃. Using the ceramics as solid electrolytes and porous platinum as electrodes, the measurements of conductivities and ionic transport numbers of the ceramic samples were performed by using ac impedance spectroscopy and gas concentration cell methods in the temperature range of 600 1000℃under the different atmospheres, respectively. The results show that in the wet hydrogen the protonic transport number of the sample was close to unity and it was almost a pure protonic conductor with the maximum protonic conductivity of 10-2 S·cm-1. In dry air, the samples are a mixed conductor of oxide-ion and hole with the oxide-ionic transport numbers of 0.1 0.25. In wet air, the samples are a mixed conductor of oxide-ion,the proton and hole. The dopant content x in the samples remarkably influenced the conduction properties. SrCe_0.9Ho_0.1O_3-α has the highest ionic conductivity among the samples.