Ionic conductivity, sintering and thermal expansion behaviors of mixed ion conductor BaZr0.1Ce0.7Y0.1Yb0.1O3-δ prepared by ethylene diamine tetraacetic acid assisted glycine nitrate process

BaZr0.1Ce0.7Y0.1Yb0.1O3-delta as a candidate electrolyte material is prepared by ethylene diamine tetraacetic acid assisted glycine-nitrate process. After calcining at 900 degrees C, the single-phase perovskite is obtained due to the better distribution of starting materials and the more feasible reaction kinetic conditions than solid state reaction method. The relative densities reach 96.8 and 98.4% respectively after sintering the pressed pellets at 1280 and 1400 degrees C for 10 h. In humidified oxygen the ionic conductivities are 0.015, 0.045, 0.101 and 0.207 S cm(-1) at 500, 600, 700 and 800 degrees C, respectively. In air and humidified oxygen the activation energies for ionic conductivity are 66.1 and 68.9 kJ mol(-1). In humidified hydrogen, however, different activation energies occur in low and high temperature ranges. The thermal expansion curve inflections at 500-800 degrees C with respect to possible phase changes are found. Zirconia aggregation possibly results in the higher activation energy and peculiar thermal expansion behavior. The results indicate the ethylene diamine tetraacetic acid assisted glycine-nitrate process is a very promising preparation method for solid oxide fuel cell practical application. (C) 2011 Elsevier B.V. All rights reserved.