Structure and conductivity of zirconium-doped polycrystalline lithium yttrium oxide

Zr-doped and undoped lithium yttrate polycrystalline samples were prepared to study the effects of zirconium-doping on the structure and conductivity of LiYO2. The solubility of zirconium oxide and the stable crystal structures were determined by X-ray diffraction. It was found that less than 1 at % Zr was sufficient to stabilize the tetragonal structure. The conductivity of the Zr-doped lithium yttrate samples was measured from 200 to 550°C by ac complex impedance analysis. Undoped LiYO2 showed the best conductivity which at 400°C was 3×10−3 S/cm. Therefore LiYO2 is a potential solid electrolyte for high temperature lithium sensors and other solid ionic devices.