Abstract: Materials formulated Ce_0.87Sm_0.13-xPr_xO_2-δ(x=0.00, 0.01, 0.02) were prepared by solgel method. Structural and electrical properties of the materials were investigated by means of X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM)and AC impedance spectroscopy. The effects of small amounts of Pr doping on microstructure and electrical conductivity of the material were discussed. The results show that the Pr doping could reduce or eliminatethe dents and pores on the grain surface and the grain boundary, which results in the lower electrode interface and grain boundary resistance. The relative density of the materials is increased remarkably. And the contribution of grain boundary resistance to the total resistance is reduced significantly.

Key words: solid state electrolyte, conductivity, grain boundary, solid oxide fuel cell (SOFC)