LAUSR

Abstract The rare–earth–doped ceria overcomes the difficulties of yttria–stabilized zirconia (YSZ) as an electrolyte in Solid Oxide Fuel Cells (SOFCs) due to its superior ionic conductivity in the intermediate temperature range. However, several factors such as synthesis process, sintering condition, dopant concentration, co–doping mechanism, dopant vacancy interaction, ionic radius of dopants, grain boundary, grain size, affect the ionic conductivity of the rare earth doped ceria. It is difficult to explain the ionic conductivity of rare–earth–doped ceria in terms of a single factor because there is a complex correlation among these factors. This review tries to find the complicated relationship between these factors. This work also reviews different opinions regarding the effect of these factors on ionic conductivity. The knowledge about the factors is vital to develop a better solid electrolyte for SOFCs. This work is an overview of the ionic conductivity of rare–earth–doped ceria in terms of the several affecting factors.