Synthesis and characterization of Gd and Er co-doped ceria as solid electrolyte for IT-SOFC via solid state method

Ceria has higher conductivity than the conventional SOFC electrolyte, yttria-stabilized zirconia (YZS) but has the drawback of measurable electronic conductivity, particularly at high temperatures. The aims of this work research are to synthesize several Gd and Er co-doped ceria materials as solid electrolyte for Intermediate Temperature Solid Oxide Fuel Cell (IT-SOFC) and to obtain the correlation between the average ionic radius of dopants and the value of their conductivity. Three set material have been choosen as target of this research. They are Ce_1-x-yGd_xEr_yO_2-z (CeGdEr); Ce_1-x-yGd_xDy_yO_2-z (CeGdDy); and Ce_1-x-yGd_xNd_yO_2-z (CeGdNd). In this paper, one set material of CeGdEr have been synthesized, they are Ce90Gd5Er5, Ce85Gd5Er10, Ce85Gd10Er5, and Ce80Gd10Er10. Their structures have been investigated using X-Ray Diffraction (XRD) and refined it using Le Bail method. All material have the similar structure that is cubic structure with space group Fm3m, but only a little differences at their lattice parameter. The lattice parameter for Ce90Gd5Er5, Ce85Gd5Er10, Ce85Gd10Er5, and Ce80Gd10Er10 are 5,406(9) Å; 5,434(1) Å; 5,434(1) Å; and 5,430(2) Å, respectively. Moreover, Ce90Gd5rEr5 morphology have been investigated using Scanning Electron Microscope (SEM). The result is Ce90G5Er5 still has pore probably due to the low temperature of sintering. The result of EDS characterization show that there is no impurity in Ce90Gd5Er5 material.