Synthesis and Characterization of Ba_0.96Sr_0.04Ce_0.7Zr_0.3O₃ Solid Oxide Fuel Cell Electrolyte by Citrate EDTA Complexing Sol-Gel Process

Abstract

This paper reports on the effect of Strontium doping on BaCe0.7Zr0.3O3 electrolyte prepared using the citrate-EDTA complexing sol-gel process at temperature T=1000°C. The phase formation and evolution with the temperature has been studied by X-ray diffraction (XRD), thermal analysis (TG-DTA).The morphology of the sintered powder at T=1300°C are examined by SEM - Scanning Electron MicroscopyEDAX - Energy-dispersive X-ray spectroscopy analysisFTIR - Fourier transforms infrared spectrometer FTRS-Raman measurementsThe crystallite size of the ceramic powders calculated from Scherrer equation is 28nm and the diffraction peak shifted to higher angles. Microstructure of the sintered powder revealed that the average grain size is in the range of 2mm. The incorporation of Sr is found to suppress the formation of CeO2 like second phase and enhance the grain growth in sintered oxides. Dense ceramic materials were obtained at 1300°C and the relative density is 80% of the theoretical density. FTIR and Raman measurements reveal the complete single phase formation of the orthorhombic perovskite structure. The ionic conductivity of the pellet is investigated from room temperature to 400°C and is found to be 1.1x10-4S/cm (400°C). The conductivity increased as temperature increases and the activation energies is 0.48eV and hence this composition qualifies to be a promising electrolyte.