The effect of Ga3+ and Cu2+ co-doping on ionic conductivity of Ceria Ceramics as Solid Electrolyte for IT-SOFCs
The current investigation draw an attention to the effect of Ga3+ and Cu2+ addition on the structure, surface morphology and oxygen-ionic conductivity of ceria ceramics in the composition Ce0.8Ga0.2-xCuxO2-d for the promising candidate as the solid electrolyte material in the solid oxide fuel cells working in intermediate temperature range (IT-SOFCs).Ultrafine Ce0.8Ga0.2-xCuxO2-d (for 0£x£0.2) nanoceramics were prepared via glycine nitrate auto-combustion method.Phase identification, microstructure, and ionic conductivity of all the ceria ceramics were observed by powder XRD, SEM, TEM, and impedance analyses measurement were used to analyze phase identification, microstructure, and ionic conductivity of all the ceria ceramics respectively. Similar to cerium oxide cubic fluorite type structure having Fm-3m space group was confirmed by powder XRD followed by Rietveld structural analysis for all the co-doped systems. The density of all samples was found above 85% after sintering at 1300ºC for 4 hrs. The presence of oxygen vacancies in all the compositions were revealed by Raman spectra. Thermal analysis for change in weight was carried out by TGA.Thermal expansion coefficient of the developed electrolytes matches with the commonly used electrode materials.The optimum composition Ce0.8Ga0.05Cu0.15O1.825 was found to reveal the maximum ionic conductivity with least activation energy among all the existing co-doped ceria ceramics.These characteristics compose it a potential applications in the IT-SOFC as the electrolyte material.
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