Effect of transition metal oxides doping on Ce_0.9Sm_0.05Nd_0.05O_1.95 solid electrolyte materials

The effect of transition metal oxides (TMOs) CoO_1.5, FeO_1.5 and MnO₂ addition on Ce_0.9Sm_0.05Nd_0.05O_1.95 was studied. The crystal structures, microstructures, thermal expansion and electrical properties were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), dilatometer and AC impedance spectroscopy, respectively. The results show that the TMOs addition remarkably promotes the densification of Ce_0.9Sm_0.05Nd_0.05O_1.95 and reduces the sintering temperature by ∼150 °C. The samples with TMOs addition sintered at 1450 °C exhibit higher conductivities than those sintered at 1500 °C. The maximum conductivity of 0.040 s.cm⁻¹ at 700 °C was achieved with 1 mol% FeO_1.5 doping when sintered at 1450 °C. In addition, the thermal expansion was linear for all the samples. The doping of TMOs does not appreciably change thermal expansion coefficient.