Shrinkage Behavior, Thermal Expansion Behavior, and Electrical Conductivity Study of Samarium Doped Ceria Electrolytes

Abstract

Ceria-based electrolytes generally have high sintering temperatures (~1500 °C)1,2, which increases the cell fabrication cost and decreases the mechanical stability of the cell due to rapid grain growth. In this work, the Ce0.9Sm0.1O2 (SDC) electrolyte is synthesized by microwave-assisted co-precipitation method using ethanol as a solvent. The sintering behavior of the green compact is studied using a dilatometer. Linear shrinkage and shrinkage rate behavior study shows a low sintering end temperature (1200 °C) and a final relative density of ~92%. A maximum linear shrinkage of -15.70% is observed at 1200 °C. A uni-modal shrinkage rate curve is seen, which confirms uni-modal pore size distribution in the powder. After 1388 °C, a dedensification is observed (+ 0.29% linear shrinkage), which might be associated with the reduction of Ce4+ to Ce3+ (please see Figure 1). Initial sintering results suggest that the synthesis method used has significantly lowered the SDC electrolyte's sintering temperature. Although the densification is completed at 1200 °C, the microstructure may change with further increase in the sintering temperature, affecting electrical conductivity. Inspired by the initial results, a detailed study on the effect of sintering temperature (1200 °C to 1500 °C) on the microstructure and electrical conductivity of SDC will be carried out and presented in the paper. S. Medisetti et al., Nano-Structures & Nano-Objects, 11, 7–12 (2017) https://www.sciencedirect.com/science/article/pii/S2352507X16301275.G. Accardo et al., J. Appl. Biomater. Funct. Mater., 14, 35–41 (2016) https://journals.sagepub.com/doi/abs/10.5301/jabfm.5000265. Figure 1