Electrical properties of Ce0.9Gd0.1O2−δ ceramics with different grain size uniformity

In this work, the effect of grain size and uniformity of the precursor powder on the electrical property of ceria based electrolytes was investigated. Gadolinia-doped ceria (GDC) samples were treated under different calcination temperatures (600 °C and 1300 °C), where their grain size and uniformity were adjusted by varying the ratio of 1300 °C powder in precursors. The phase composition, morphology and conductivities of mixed GDC samples were characterized by x-ray diffraction (XRD), scanning electron spectroscopy (SEM) and AC impedance, respectively. XRD results revealed that all GDC samples are single cubic fluorite-type structures. As the content of 1300 °C powder increased, the grain boundary conductivity first dropped markedly to the minimum at the ratio x = 5% and then basically unchanged, whereas no significant change was observed in bulk conductivity. Our study demonstrated that the ratio of the higher calcination temperature powder in the mixed precursor powder gave rise to the variation of grain size uniformity and the electrical properties of GDC samples.