Structural, micro-structural, ionic-conductivity and thermal expansion study of Ce0.76Sm0.08Nd0.08Y0.08O2–δ electrolyte for IT-SOFC applications

The development of solid electrolyte with enhanced properties towards intermediate temperature - solid oxide fuel cells (IT-SOFCs) remains an R&D issue. The present work deals with the study of novel Sm³⁺/Nd³⁺/Y³⁺ Tri-doped ceria (Ce_0.76Sm_0.08Nd_0.08Y_0.08O_2–δ) Solid Electrolyte towards IT-SOFCs. The Ce_0.76Sm_0.08Nd_0.08Y_0.08O_2–δ was synthesized via Sol-Gel technique, calcined/sintered at 800 °C/1300 °C and followed by the characterization of PXRD, SEM, HR-TEM, XPS, Raman, Impedance spectroscopy and Thermal expansion studies respectively. PXRD confirmed that the prepared sample displayed a single phase cubic fluorite-type structure. The crystallographic parameters were also perceived from the PXRD refinement analysis. Further surface microstructure, structural, and element analysis were examined using SEM, HR-TEM, XPS, and Raman studies. Electrical parameters i.e. ionic-conductivity along with activation energy were calculated for CSNY by using impedance studies. It was found that tri-doped ceria Ce_0.76Sm_0.08Nd_0.08Y_0.08O_2–δ sample revealed the total-ionic-conductivity of 0.027 Scm⁻¹ at 600 °C along with activation energy of 0.81eV. The matched thermal expansion coefficient of CSNY i.e. 12.77 × 10⁻⁶ °C⁻¹ was revealed by the Thermal expansion study. Thus, it can be concluded that the prepared tri-doped ceria CSNY could be a capable solid-electrolyte in IT-SOFCs.