Tailoring of properties in the preparation level of nano crystalline Ce0.8Sm0.2O1.9-δ(SDC) for the use of SOFC electrolyte

Abstract

Ce0.8Sm0.2O1.9-δ (SDC) has been a potential candidate for SOFC electrolyte for its compatibility with other cell components such as with Lanthanum ferrite based electrodes. Crystalline Ce0.8Sm0.2O1.9-δ (SDC) has been synthesized by a novel combustion route. A fuel rich configuration of the precursors favours the formation of agglomerate free fine particles. The XRD pattern of the powder has been observed as a function of calcination temperature. As synthesis powder has been observed phase pure except with traces of residual carbon impurities as has been observed from the FTIR pattern. The purity of the as synthesized powder has been attributed to the optimized value of elemental stoichiometric coefficient, which in turn has been attributed to the supplement of optimized thermal energy to the precursor gel. The crystallite size has been calculated and compared for the different calcination temperatures which as expected, has enhanced with the calcinations temperature. The chemical reactivity with LSCF cathode material tested under XRD reveals no reactive phase formed in the operating temperature range. The FESEM image of the powder reveals the fineness of the powder and its homogeneity. Circular discs have been pressed and sintered for densification. Density above 96% was observed from the measurement. The SEM of the sintered pellet has been checked for phase purity and pure crystalline XRD peaks confirmed the crystalline character. The sintering temperature 1450 °C has been observed to be one of the lowest of the reported values. It was attributed to the fine powder with high surface area.The study facilitates a combustion synthesis of ceramic oxide powder in general and of SDC in particular at comparatively low temperatures such as those 550 °C or even lower.