Effects of Mg2+ addition on structure and electrical properties of gadolinium doped ceria electrolyte ceramics

Series of Gd3+ and Mg2+ co-doped ceria (Ce0.8Gd0.2-xMgxO1.9-?) powders were prepared by a sol-gel method and electrolyte ceramics were obtained by sintering at 1300?C. Thermogravimetric and differential scanning calorimetry, X-ray diffraction, scanning electron microscope and electrochemical impedance spectroscopy were used for structural, morphology and electrical characterization of the prepared samples. Well crystalline cubic fluorite structured composite was confirmed after calcination at 700?C and the electrolyte ceramics sintered at 1300?C for 4 h was quite dense with uniform microstructure. The electrochemical analysis results displayed that the highest conductivity has the Ce0.8Gd0.14Mg0.06O1.87 compound, i.e. 0.0203 S/cm at 800?C. Therefore, it was concluded that co-doping with Gd3+ and Mg2+ could enhance the electrical properties of the CeO2 based solid electrolytes.