Alkaline earth metal and samarium co-doped ceria as efficient electrolytes

Abstract

Co-doped ceramic electrolytes M0.1Sm0.1Ce0.8O2−δ (M = Ba, Ca, Mg, and Sr) were synthesized via co-precipitation. The focus of this study was to highlight the effects of alkaline earth metals in doped ceria on the microstructure, densification, conductivity, and performance. The ionic conductivity comparisons of prepared electrolytes in the air atmosphere were studied. It has been observed that Ca0.1Sm0.1Ce0.8O2−δ shows the highest conductivity of 0.124 Scm−1 at 650 °C and a lower activation energy of 0.48 eV. The cell shows a maximum power density of 630 mW cm−2 at 650 °C using hydrogen fuel. The enhancement in conductivity and performance was due to increasing the oxygen vacancies in the ceria lattice with the increasing dopant concentration. The bandgap was calculated from UV-Vis data, which shows a red shift when compared with pure ceria. The average crystallite size is in the range of 37–49 nm. DFT was used to analyze the co-doping structure, and the calculated lattice parameter was compared with the experimental lattice parameter.