Ceramic Electrolytes in the CeO2-Gd2O3-SrO System - Preparation, Properties and Application for Solid Oxide Fuel Cells

Both Pechini method (A) and hydrothermal treatment of co-precipitated gels (B) solutions were used to synthesize nanopowders of Ce-0.8-xGd(0.2)Sr(x)O(2-delta) for 0<x<0.1 solid solutions. All resulting powders and sinters were found to be cubic ceria-based solid solutions. The results of hardness, fracture toughness and bending strength measurements are reported for the sintered samples of the CeO2-SrO-Gd2O3 system. The electrical properties a of ceria-based solid solutions were studied by a. c impedance spectroscopy in the temperature range 200-700 degrees C. It was found that incorporation of a small amount of cation Sr2+ into solid solution Ce(0.8-x)Gd(0.2)SrxO(2-delta) 0<x<0.03 allowed an increase, in the ionic conductivity of a Ce0.8Gd0.2O2-delta oxide electrolyte. Selected materials from the CeO2-Gd2O3-SrO system were tested as oxide membranes in solid oxide fuel cells operating in the temperature range 500-800 degrees C. The higher current and power density received from IT-SOFCs with a new electrolyte Ce0.78Gd0.2Sr0.02O2-. were recorded and compared to the same IT-SOFC involving Ce0.8Gd0.2O2-delta as an electrolyte.