Chemistry of formation of a solid oxide fuel cell electrolyte (yttria stabilized zironia)

The chemistry of formation of yttria stabilised zirconia (a material commonly used as an electrolyte in solid oxide fuel cells) via precipitation of a dawsonite like compound, (NH4)xZr(OH)y(CO3)z, was investigated using Fourier Transform Infrared Attenuated Total Reflectance spectroscopy (FTIR-ATR), Thermogravimetric Analysis (TGA) and in-situ temperature controlled x-ray diffraction (XRD). FTIR-ATR studies indicated a shared mechanism in the precipitation reaction at pH 6 and 8 that did not occur at pH 7. TGA and XRD studies however showed that precipitates formed at pH 6 and 7 were significantly different in terms of thermal properties (combustible and /or volatile content) and structure compared to the precipitate obtained at pH 8. The results obtained indicate that a relatively small change in pH (from pH 7-8) can have a significant effect on the precipitate formed.