In this study, the synthesis of Ce0.8Sm0.2O1.9 (SDC) solid electrolyte by the ultrasound assisted co-precipitation method was accomplished to explore the effects of ultrasound power, ultrasound pulse ratio and probe type upon the ionic conductivity of SDC as well as the lattice parameter, the microstructure and the density. Fine powders of uniform crystallite sizes (average 11.70 +/- 0.62 nm) were obtained, needing lower sintering temperature. The SDC powders were successfully sintered to a relative density of over 95% at 1200 degrees C (5 degrees C min(-1)) for 6 h. The micrograph of SDC pellets showed non-agglomerated and well-developed grains with average size of about 200 nm. X-ray diffraction analysis showed that the lattice parameter increased with increasing acoustic intensity and reached a maximum for the 14.94 W cm(-2). Further, a linear relationship was detected between the lattice parameter and the ionic conductivity, inspiring a dopant like effect of US on the electrolyte properties. The highest ionic conductivity as sigma(800 degrees C) = 3.07 x 10(-2) S cm(-1) with an activation energy E-a = 0.871 kJ mol(-1) was obtained with pulsed ultrasound for an acoustic intensity of 14.94W cm(-2), using 19 mm probe and 8:2 pulse ratio. (C) 2012 Elsevier B.V. All rights reserved.