The influence of sintering additive on the structure and intermediate-temperature electrochemical properties of Gd3+ and Er3+ co-doped ceria electrolyte

In this study, Er0.1Gd0.1Ce0.8O2-alpha (EGDC) was synthesized at different temperatures by a nitrate-citric acid combustion method. Er0.1Gd0.1Ce0.8O2-alpha-4 mol% NiO (EGDC-NiO) was also prepared by adding 4 mol% NiO as a sintering additive. The morphologies and structures of 1350-EGDC, 1450-EGDC and 1350-EGDC-NiO were investigated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Intermediate-temperature electrochemical properties were also studied using AC impedance, gas concentration cell and fuel cell. SEM results showed that adding sintering additive NiO or increasing sintering temperature can improve the densities of electrolytes. The log(sigma T) vs. 1000T(-1) results showed that 1350-EGDC-NiO had the highest conductivity of 5.3 x 10(-2) S.cm(-1) at 750 degrees C. The maximum output power densities of 1350-EGDC, 1450-EGDC and 1350-EGDC-NiO were 34.8 mW.cm(-2), 56.8 mW.cm(-2) and 63.6 mW.cm(-2) at 750 degrees C, respectively.