Anode-supported yttria stabilized zirconia (YSZ)/samaria doped ceria (SDC) bi-layer electrolytes with uniform thickness and high density were fabricated by pulsed laser deposition at 1000 degrees C. Fuel cells with such bi-layer electrolytes were fabricated and tested, yielding open circuit voltages from 0.94 to 1.0 V at 600-700 degrees C. Power densities from 0.4 to 1.0 W cm(-2) at 0.7V were achieved in air at temperatures of 600-700 degrees C. Cell performance was improved in flowing oxygen, with an estimated peak power density of over 2 W cm(-2) at 650 degrees C, assuming the same overall resistance over the entire range of current density. The high cell performance was attributed to the very low ohmic resistance of the fuel cell, owing to the small thickness of the electrolyte. Stable performance was also demonstrated in that the voltage of the fuel cell showed very little change at a constant current density of 1 A cm(-2) during more than 400h of operation at 650 degrees C in flowing oxygen. SEM analysis of the fuel cell after testing showed that the bi-layer electrolyte had retained its chemical and mechanical integrity. Published by Elsevier B.V.