Carbonate Co-precipitation synthesis and Ionic conducting properties of Gd-doped CeO_2

The solid electrolyte,Ce0.8Gd0.2O2.0-δ(GDC) was successfully prepared via a carbonate co-precipitation reaction using ammonium hydrogen carbonate as precipitant.XRD revealed that the co-precipitation powder had a single cubic fluorite structure of ceria after calcined at 600℃ for 2 h.Ceramics with different densities and grain sizes were obtained after sintered at different temperatures.A relative density of 96.7% was obtained after sintered at 1250℃ for 4h.AC impedance spectroscopy results revealed that the 1250℃ sintered GDC ceramic provided the highest oxygen ionic conductivity of 1.1×10-2 S/cm at measuring temperature of 600℃ in all samples,together with the lowest activation energy of conductance of 0.63 eV in the measuring temperature range of 350-600℃.1250℃ was an appropriate sintering temperature for GDC nano-materials synthesized via a carbonate co-precipitation method,further higher sintering temperature would lower the ionic conductivity.