The application of conventional zirconia-based electrolytes is limited to relatively high temperatures (ie > 750 degrees C) due to their poor conductivities at low temperatures. Doped ceria has much higher conductivities; however, when exposed to fuel, electronic current develops within the material, which impairs cell performance and efficiency. Herein, we report a novel layered electrolyte structure consisting of a 10 mu m samaria-doped ceria primary layer and a 2 mu m scandia-ceria-stabilized zirconia protection layer on the fuel side. The cell had five layers and was fabricated using a tape casting and ultrasonic spraying technique. By carefully selecting the raw materials, the bilyer electrolyte was sintered to full density at a low temperature of 1250 degrees C. The adverse interdiffusion and undesirable reactions between the two layers were largely avoided. A fuel cell with the layered electrolyte structure, operated on hydrogen fuel, produced a high open circuit voltage 1.07 V and a power density of 321 mW/cm(2) at 0.8 V and 600 degrees C, 76% improvement compared to the fuel cell with a scandia-stabilized zirconia/samaria-doped ceria bilayer electrolyte reported in literature.