Fuel cell technology: Synthesis and electrical properties of electrolyte for intermediate temperature

Ce0.9gd0.1o2-γ fine powder has been synthesized by a simple and fast hydrothermal method at relatively low temperature (140 °c) from high-purity commercial ceo2 and gd2o3. the x ray diffraction results showed that the crystalline powder is single phase with cubic fluorite structure; the average crystallite size was about 8.6 nm. the electrolyte pellets sintered at 1100-1300 °c were dense,with relative densities over 96%. impedance spectroscopy was used to analyze the electrical transport properties between 150-1000 °c,with a systematic deconvolution of bulk and grain boundary properties in the lower temperature range. the results evidenced an improvement of the total conductivity in the low-temperature regime for sample sintered at 1100 °c,which was ascribed to an enhancement of the grain boundary properties. the implementation of the space charge layer model was used to identify modifications of the space charge potential with the sintering temperature.