Preparation and characterization of ceria co-doped with Ca and Mg

Abstract

The aim of the present investigation was to study the effect of doping of magnesium and calcium on the ionic conductivity of CeO 2 in the system Ce 1 - xCa x - yMg yO 2 - x (x = 0.150) for its use as a solid electrolyte in the intermediate temperature solid oxide fuel cells (IT SOFC).Attempts have been made to synthesize a few compositions in this system with x = 0.150 and y = 0.000, 0.050, 0.060, 0.065 and 0.070. The precursor materials have been synthesized by auto-combustion method. Solid solution forms in compositions with y ≤ 0.060. Microstructures of thermally etched samples have been studied by scanning electron microscopy (SEM). In order to evaluate the total electrical conductivity, σ t, use is made of complex plane impedance analysis. Impedance measurements were made in the frequency range 1 Hz-1 MHz and temperature range 250-500 °C. It is found that co-doped samples show higher conductivity than undoped and singly doped samples. © 2012 Elsevier B.V. All rights reserved.