Rare Earth Co-doped Nanocrystalline Ceria Electrolytes for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFC)

摘要

Samaria doped ceria (SDC) co-doped with Nd_2O_3 (Nd-SDC) and doubly co-doped with Nd_2O_3 and Pr_2O_3 (Pr-Nd-SDC) was prepared by solution combustion synthesis. X-ray diffraction studies confirmed the nanocrystalline nature of the powder with cubic fluorite phase. Raman spectroscopy showed the characteristic cubic fluorite peak (464 cm~(-1)) of ceria and the vacancy concentration calculated from the peak area ratio (A_(550)/A_(464)) was found to be higher in Pr-Nd-SDC (0.556) compared to Nd-SDC (0.168). The powder was compacted into discs and sintered to obtain dense pellets. The sintering temperature was found to be considerably lower than that required for microcrystalline SDC. The electrical conductivity was obtained by impedance spectroscopy. The doubly co-doped sample (Pr-Nd-SDC) exhibited higher conductivity and lower activation energy compared to the co-doped sample (Nd-SDC).