Crystal Structure and Electrical Properties of Magnesia Co-Doped Scandia Stabilized Zirconia

Abstract

Mg-doping effects on the crystal structure and ion conduction properties of Scandia Stabilized Zirconia have been studied in the (ZrO 2) 0.89 (Sc 2 O 3) 0.11-x (MgO) x (0  x  0.07) system. The materials have been prepared by a sol-gel method. Characterization of the crystal structure has been carried out by means of X-ray diffraction, Raman spectroscopy, synchrotron X-ray diffraction, selected area electron diffraction and high resolution transmission electron microscopy. Cubic phase-stabilization is observed in materials corresponding to x ≥ 0.03 but single cubic-phase formation is achieved only in (ZrO 2) 0.89 (Sc 2 O 3) 0.08 (MgO) 0.03. Ionic conductivity of the oxides has been determined by complex impedance spoectroscopy. Stabilization of the cubic phase in the compounds with x ≥ 0.03 values avoids rhombohedral-cubic phase transformation, improving the conductivity bellow 600 ºC compare to the one of 11ScSZ.

Structural and Electrochemical Properties of Scandia Alumina Stabilized Zirconia Thin Films

“…Therefore, dimers and trimers did not form, and the Arrhenius plots had only one slope. In general, the total ionic conductivity achieved was similar to other authors [8,9,13,15,36,[44][45][46][47][48][49][50][51][52]. The highest total conductivity values were found for thin films containing 3.8 at.% of Al.…”

Advanced modification of scandia‐stabilized zirconia electrolytes for solid oxide fuel cells application—A review

“…Without Mg co‐doping, the ionic conductivity of ScSZ electrolyte has dropped at 600°C. The Mg doped‐ScSZ electrolyte ionic conductivity was sustained from high to low operating temperatures 89 . Besides, the presence of 2 mol% bismuth co‐doping within the ScSZ electrolyte significantly influenced the cubic structure stabilization in the low‐to‐intermediate operating temperature of SOFCs.…”

“…As seen in Figure 4, the movement of ion oxide migrated within the solid electrolyte by a hopping mechanism through a single structure unoccupied (ie, at green arrow) and a series of oxygen vacancies (ie, at yellow arrow). 87 Several additional trivalent cations have been introduced to the ScSZ electrolyte, including ceria codoping, 84 dysprosium co-doping, 85 ytterbia co-doping, 88 magnesia co-doping, 89 and bismuth co-doping. 90 The optimum concentration of co-doping was an important parameter to be measured in order to achieve the high efficiency of the solid electrolyte.…”

“…Without Mg codoping, the ionic conductivity of ScSZ electrolyte has dropped at 600 C. The Mg doped-ScSZ electrolyte ionic conductivity was sustained from high to low operating temperatures. 89 Besides, the presence of 2 mol% bismuth co-doping within the ScSZ electrolyte significantly influenced the cubic structure stabilization in the low-tointermediate operating temperature of SOFCs. In order to preserve a stabilized cubic phase, the sample must be calcined at 1200 C. The high calcination temperature will cause the rhombohedral phase formation of the solid electrolyte.…”

“…Several additional trivalent cations have been introduced to the ScSZ electrolyte, including ceria co‐doping, 84 dysprosium co‐doping, 85 ytterbia co‐doping, 88 magnesia co‐doping, 89 and bismuth co‐doping 90 . The optimum concentration of co‐doping was an important parameter to be measured in order to achieve the high efficiency of the solid electrolyte.…”