Synthesis and Characterization of Sc and Y Co-doped Zirconia (Zr0.84Y0.08Sc0.08O1.92) Electrolyte Prepared by Sol-Gel Method

Y and Sc co-doped ZrO2 [Zr0.84Y0.08Sc0.08O1.92 (4Sc4YSZ)] solid electrolyte was prepared via an alkoxide sol-gel route. 4Sc4YSZ was characterized by TG-DTA, XRD, SEM-EDS and AC impedance spectroscopy. XRD patterns showed that co-doping with Y and Sc resulted to the successful stabilization of the highly conductive cubic phase with a lattice parameter of 5.12 Å. Y and Sc dopants are well-distributed within the ZrO2 particles as evidenced by EDS elemental maps. Total conductivities from 500 °C to 700 °C were determined from AC impedance spectroscopy and an activation energy of 1.31 eV (500-650 °C) was calculated. Even at a low sintering condition of 1200 °C for 5 h, a promising conductivity of 109 mS/cm was achieved for 4Sc4YSZ at 700 °C which is higher than the conductivity of typical 8YSZ solid electrolyte.