(Yb2O3)(x)(Dy2O3)(y)(Bi2O3)(1-x-y) (0.04x+y0.20) powders (xYbyDSB) were synthesized by modified sol-gel Pecchini method. The powders were characterized for structural, surface morphological, thermal, and electrical properties and power density measurements by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), differential thermal analysis/thermal gravimetry (DTA/TG), and impedance spectroscopy, respectively. Lattice parameters and crystalline size of -phase of Yb2O3- and Dy2O3-doped Bi2O3 samples were calculated from the X-ray diffraction data. Surface and grain properties of the related phases were determined by SEM analysis. In the investigated system, the maximum electrical conductivity was observed as sigma=0.954 S cm(-1) for 6% mol Yb2O3 and 6% mol Dy2O3 at 800 degrees C among all -YbDSB systems. Cathode supported electrochemical cell was fabricated and 6Yb6DSB was used as the electrolyte. Maximum power density of single cell with an active area of 1.5 cm(2) is 72.50 mW/cm(2) at 700 degrees C.