Effect of sintering temperature on structural and electrical properties of co-doped ceria based electrolyte material for IT-SOFCs

摘要

Solid oxide fuel cells (SOFCs) are considered an alternative electric power generation systems due to high energy conversion efficiency, fuel flexibility, and operation directly on natural gas. One important challenge in SOFC commercialization is to reduce its operating temperature to intermediate temperature (IT) range. Ceria based material has shown potential to enhance oxy ion conductivity by aliovalent doping. Co-doping approach is strategically applied as it gives more flexibility in a valence-size mismatch in host lattice of ceria and thus more degrees of freedom for materials behavior manipulation. In ceria for every two trivalent or one divalent dopant ions that replace Ce~(4+) ions, one oxygen vacancy is generated to balance the charge. Sm and Sr as co-doping approach contribute to oxy-ion conductivity for functioning of SOFCs. In this attempt we focused on effect of sintering temperature on structural, microstructural and electrical properties of ceria based material for IT-SOFCs. With this motivation we have synthesized Sm and Sr based co-doped ceria system (SSRDC) by hydrothermal synthesis route. We vary sintering temperature from 1100 and 1300°C. The structural and microstructural changes with respect to increasing sintering temperature and its influence on formation of oxygen vacancies and hence on ionic conductivity studied systematically.