Facile synthesis of ceria-based composite oxide materials by combustion for high-performance solid oxide fuel cells

This article proposes the preparation of promising oxide materials with a broad range of applications as electrolytic materials for solid oxide fuel cells (SOFCs). The oxide materials, namely, samarium-doped ceria Sm_0.2Ce_0.8O (SDC), gadolinium-doped ceria Gd_0.2Ce_0.8O (GDC), and calcium-doped ceria Ca_0.2Ce_0.8O (CDC), were prepared through the conventional combustion method with glycerol as a complexing agent. The thermal behavior of the materials was examined through thermogravimetry-differential scanning calorimetry measurements, and their structural and morphological properties were analyzed via X-ray diffractometry (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy. Fourier transform infrared spectroscopy confirmed the presence of the metal oxide group in the range of 400–1500 cm⁻¹. Two probe methods were used for electrical measurements. The XRD patterns obtained confirmed that the materials have cubic fluorite structures with an average crystallite size in the range of 26.8–44.7 nm. The ionic conductivities of the ceria samples were measured in the temperature between 300 and 700 °C. The samples consistently showed semiconducting behavior, with SDC exhibiting the highest ionic conductivity of 8.32 × 10⁻³ S/cm. A maximum power density of 265 mW/cm² was recorded at 650 °C when SDC was used as an electrolyte.