Solid electrolyte for intermediate temperature solid Oxide fuel cell

Abstract

Solid oxide fuel cell (SOFCs) have potential to generate high efficiency electrical energy converted from chemical energy with minimum impact to the environment. This thesis were aimed to study the structure and electrical properties of the solid electrolyte materials to be used at its intermediate temperature. Samarium doped ceria, Sm0.2Ce0.8O1.9 is Ceria-base electrolyte which reported as the highest electrical conductivity, were prepared by solid state method. Sm0.2Ce0.8O1.9 act as parent sample. Its pure phase obtained at 1500 oC heated for 24 h with intermittence grinding process. On the other hand, parent sample were doped with erbium which is its correlated tetravalent cation and were compared. Thus, the aliovalent doping is studied. The prepared samples, Sm0.2-xErxCe0.8O1.9 for (0≤ x ≤ 0.10) were compared to determine its structure and electrical properties. X-Ray Diffraction (XRD) analysis result showed that all samples were formed within its solid solution with cubic symmetry and space group of Fm-3m. Besides, the crystal structure remained stable when doped with erbium (0≤x≤0.10) and sintered at 1350 oC for 5 h. Lattice parameters and unit cell volume of Sm0.2-xErxCe0.8O1.9 for (0≤x≤0.10) were similar and within errors. Nevertheless, crystallite size calculated using Scherrer’s equation by Diffract.Eva Software showed Sm0.2-xErxCe0.8O1.9 for (0.05≤x≤0.10) is relatively larger than Sm0.2-xErxCe0.8O1.9 for (x=0). In addition, the measured electrical conductivities of Sm0.2-xErxCe0.8O1.9 for (0≤x≤0.05) were at range 10-5 to 10-7 and 10-5 to 10-6 S cm-1 at 500 oC respectively. The structure of Sm0.2-xErxCe0.8O1.9 for (0≤x≤0.05) are similar and comparable to ICDD Database PDF Card No.: 01-075-0158 but the electrical properties of Sm0.2-xErxCe0.8O1.9 for (x = 0.05) is relatively better than parent sample, Sm0.2Ce0.8O1.9.