Preparation and characterization of Al and La co-doped (Ce1-x-yAlxLayO2-(x+y)/2) ceria

Abstract

Effect of co-doping of lanthanum and aluminum on ionic conductivity of CeO2 for its use as a solid electrolyte in intermediate temperature solid oxide fuel cells has been studied. A few compositions in the system Ce1-x-yAlxLayO2-(x + y)/2 (CAL) with x = 0.05, 0.025, and 0.00 and y = 0.00, 0.025, and 0.05 such that x + y = 0.05 are prepared by auto-combustion method. X-ray diffraction patterns show that all the synthesized samples are ceria-based solid solutions. Microstructures of thermally etched samples have been studied by scanning electron microscope. To determine the contribution of grains, σg and grain boundaries, σgb to the total conductivity, σt impedance is measured in the frequency range 1-1 MHz at different steady temperatures in the range 250-500 °C. It has been found that conductivity of the co-doped composition is more than singly doped with Al but less than singly doped lanthanum composition. © 2012 Springer-Verlag.