Relation between proton and hole conduction in SrCeO3-based solid electrolytes under water-containing atmospheres at high temperatures

Abstract Electrical conduction in the solid proton electrolyte based on SrCeO3 was studied under water-containing atmospheres at high temperatures. The change of conductivity was measured systematically as a function of the concentration of the dopant or of the partial pressures of water vapor and oxygen. Since the conduction in the oxides was not purely protonic but partially electronic, these conductivities were determined separately using a steam concentration cell. It was observed that the proton conductivity increased in proportion to P 1 2 H2O and was independent of PO2. It was also recognized that the electronic conduction present in the oxides was due to holes and the hole conductivity followed the P 1 4 O2 law. A possible model for the proton formation in the oxides is discussed and it is proposed that the protons might be produced from water vapor at the expense of holes.