Low temperature sintering of solid oxide fuel cell electrolytes

Solid oxide fuel cells provide a clean and efficient means to produce electricity. Gadolinium oxide doped ceria is considered to be an ideal electrolyte material for SOFC’s operating at temperatures between 500-600°C. Typically, this material is sintered to high density at approximately 1300°C. Reducing this temperature to ~1000°C will enable ferritic stainless steel to be used as a cell supporting material, thus significantly reducing cost and potentially enhancing the mechanical reliability of the stack. The aim of this study is to devise a method for sintering Gd doped ceria to high density at temperatures between 900-1000°C with no detrimental effects on its electrical properties. A number of experimental techniques were employed to characterise the sintering process and the resulting materials including, a.c. impedance spectroscopy, dilatometry, four-point d.c resistivity, Raman spectroscopy, transmission electron microscopy and x-ray photoelectron spectroscopy. Gd doped ceria was successfully sintered to high density at