Tailoring the activation energy and the ionic properties of bismuth codoped SDC powder prepared by solid-state reaction method

Research on fuel cell components has received great attention owing to the growing need for sustainable energy sources. Bismuth (Bi³⁺) codoped samarium-doped cerium oxide [Ce_1−xSm_x−yBi_yO_2−δ (x = 0.2 and y = 0, 0.05 and 0.1)] nanosystems were prepared by solid-state reaction method. Rietveld structure refinement of X-ray diffraction pattern confirms the cubic fluorite structure along the (111) plane with the decrease in lattice distortion. At the same sintering temperature, pellets exhibit good morphology with better mechanical strength. The conductivity measurements carried out using the Nyquist plot, as well as the modulus spectra, indicate the effect of grain and grain boundary conduction at high temperatures. With the increase in the incorporation of Bi dopant, there is a gradual decrease in ionic conductivity and activation energy. The composition of Ce_0.8Sm_0.1Bi_0.1O_2−δ exhibits less ionic conductivity compared to other samples due to the oxygen vacancies attracted by dopant cations. The effect of Bi³⁺ dopants on samarium-doped ceria lattice structures and the electrical properties of the systems have been discussed.