AC Electrochemical Impedance Spectroscopy (EIS) was carried out on the samples in the air atmosphere to study the electrochemical properties of sintered samples using an impedance/gain-phase analyzer SI 1260 and electrochemical interface SI 1287 (Ametek Solartron Metrology). Platinum paste (Heraeus) was symmetrically screen-printed on both sides of the sintered pellets (electrode thickness ≈ 20 µm) and fired at 950 °C for 1ℎ. The conductivity of the sintered samples was measured in the temperature range from 300 °C to 800 °C from 1MHz to 1Hz in air with open circuit voltage (OCV) polarization and applied voltage amplitude of 10 mV.