Citrate/nitrate combustion synthesis and electrical properties of rare earth co-doped Ce0.8Gd0.2-xNdxO1.90 electrolyte materials

Abstract

In this study, effects of neodymium doping on the electrical properties of gadolinium-doped ceria were investigated. Ce0.8Gd0.2-xNdxO1.90 (x = 0.0-0.20) powders were prepared by citrate-nitrate combustion. Phase identification and morphology were carried out by XRD and SEM, respectively. All powder samples calcined at 600 degrees C were found to be ceria-based solid-solutions with a fluorite-type structure. The powders were isostatically cold-pressed and sintered in air at 1400 degrees C for 6 h to attain a sintered density of about 95% of the theoretical value. Electrical conductivity of the gadolinium-doped ceria pellets in air was studied as a function of temperature in 300-800 degrees C temperature range, utilizing two-probe electrochemical impedance spectroscopy. Ce0.80Gd0.12Nd0.08O1.90 showed higher electrical conductivity and lower activation energy (0.64 eV) than single element-doped (Gd or Nd-doped) ceria at 700 degrees C. Thus, it can be indicated as a possible candidate to function as an electrolyte in intermediate temperature solid oxide fuel cells.