Conductivity properties of lanthanide-co-doped ceria-based solid oxide electrolytes

Abstract

The doped ceria has drawn much attention as a prospective electrolyte material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The ionic conductivity of the ceria-based electrolytes was directly influenced by the valence state and type of the doped ions. Gd3+- and Nd3+-co-doped ceria–based materials (Ce0.80Gd0.2-xNdxO1.90) were prepared using the Pechini method. Co-doped samples were sintered at 1400 °C for 6 h. Structures of the samples were studied utilizing X-ray diffraction (XRD) and Fourier transform infrared spectroscopy. XRD patterns showed that all samples have a fluorite-type crystal structure similar to pristine ceria. Electrochemical impedance spectroscopy (EIS) was used to measure the total ionic conductivities of co-doped ceria electrolytes at 300–800 °C. EIS results demonstrated that Ce0.80Gd0.12Nd0.08O1.90 had the highest total conductivity at 800 °C and the lowest activation energy. It can be deduced that co-doping with suitable rare earth elements can further enhance the electrical properties of ceria-based electrolytes.