Electronic and protonic conductivities of Tb doped SrCeO3 were measured in a H containing and hydrogen-free atmosphere of the same O partial pressure at 500 to 900C. In a H2 containing atmosphere, the material exhibits mixed electronic and proton-conductivity and, for SrCe0.95Tb0.05O3-δ, the proton transfer number increased with decreasing temperature, from about 0.4 at 900C to about 0.8 at 500C. The total conductivity for SrCe0.95Tb0.05O3-δ decreased from about 3 x 10−3S/cm in the reducing atmosphere to 4 x 10−5S/cm in air at 900C with an activation energy of 39 and 76kJ/mol, respectively, for protonic and n-type electronic conduction. Results of X-ray diffraction analysis show a decrease in the lattice volume of the SrCe1-xTbxO3-δ with increasing Tb concentration. SrCe1-xTbxO3-δ exhibits negligible proton-conductivity with x smaller than 0.005. At 800C under a reducing atmosphere, SrCe1-xTbxO3-δ, with x > 0.005, were mixed electronic and proton conductors with a maximum proton-conductivity of about 3 x 10−3S/cm at x = 0.025 and proton transfer number of about 0.7 for x in the range of 0.005–0.125.

Protonic and Electronic Conductivities of Terbium Doped Strontium Cerates. X.Wei, Y.S.Lin: Solid State Ionics, 2008, 178[35-36], 1804-10