Preparation and characterization of Ce1-xGdxO2-δ (x=0.1-0.3) as solid electrolyte for intermediate temperature SOFC

The effect of Gd doping on the ionic conductivity of CeO2 for its use as a solid electrolyte material for the intermediate temperature solid oxide fuel cells (IT-SOFCs) has been explored here. Ce1-xGdxO2-delta (x = 0.1-0.3) samples are successfully synthesized by carbonate co-precipitation method. XRD, FT-IR, Raman spectroscopy, UV-Vis spectroscopy, SEM and impedance spectroscopy are used for structural and electrical characterization. From the XRD patterns, well-crystallite cubic fluorite structured solid solution is confirmed. As Gd3+ ions are doped into CeO2 lattice, the absorption spectrum exhibits a red shift when compared to CeO2. Raman spectra show a peaks at 463 cm(-1), 546 and 600 cm(-1), which are the characteristic peaks of doped ceria. Based on ac-impedance data, the total ionic conductivity is same for both Ce0.9Gd0.1O2-delta (GDC10) and Ce0.8Gd0.2O2-delta (GDC20) in the temperature range 473 K-623 K. Hence for Gd doped ceria solutions 10% and 20% of Gd, are proper doping level which leads to the maximum total conductivity. Above this doping level, the mobility of oxygen ions decreases the total conductivity due to blocking effect. (c) 2013 Elsevier B.V. All rights reserved.