Investigation of the Properties of Sodium Beta-Alumina Electrolyte in the Presence of Yttria Stabilized Zirconia and Niobium Oxide as Additives

Sodium beta Alumina electrolyte as a sodium ion conductor is used in sodium sulfur batteries. It is important to achieve appropriate ionic conductivity and mechanical properties during the manufacturing process. For that purpose, in the present work, the effect of the simultaneous use of two additives, including yttria stabilized zirconia and niobium oxide, on the properties of sodium beta alumina ceramic has been investigated. Sodium beta powder synthesized by the solid state method and the raw samples were formed by uniaxial pressing. From X-ray diffraction analysis to study the phases, a scanning electron microscope to study the microstructure of the samples, from the ring on the ring test to measure the fracture strength and impedance for measuring ion conduction were used. The results of this study showed that the ionic conductivity and fracture strength of sodium beta-alumina ceramic have improved in the presence of these two additives. Increasing ionic conductivity can be attributed to the higher density and more uniform microstructure. The presence of yttria stabilized zirconia particles, due to the prevention of crack growth, improves the mechanical properties of this electrolyte.