The research of crystal structure and electrical properties of a new electrolyte material: Scandia and Holmia stabilized Zirconia

Abstract

Weakly agglomerated nano-crystalline Ho₂O₃ and Sc₂O₃ stabilized ZrO₂ (HoScSZ) powders are prepared by the hydrothermal method. Dense HoScSZ ceramic pellets are fabricated by isostatically pressing the powders then sintering at 1350°C for 2 h. All the HoScSZ samples are cubic phase verified by X-ray diffraction. 7 mol % Sc₂O₃ + 1 mol % Ho₂O₃ stabilized zirconia (7Sc1HoSZ) is verified by impedance spectroscopy possessing the higher conductivity than that of 8 mol % Sc₂O₃ stabilized zirconia (8ScSZ). Space charge potential and specific grain boundary conductivity are calculated and fitted under the circumstance that the grain boundary is free of any amorphous phase which is verified by high resolution transmission electron microscopy. With the increase of the doping content of Ho₂O₃, the specific grain boundary conductivity and space charge potential decrease, while oxygen vacancy concentration increases.