context: Electrochemical impedance spectroscopy (EIS) measurements were performed by Pt sputtering on both sides of the solid electrolyte pellets, and electrochemical characterization was done using SUS electrodes. Biologic VSP-300 models were electrochemically tested at a frequency range of 7 MHz to 100 MHz at 10 mV. Ionic conductivity was calculated using the following expression: where σ is the ionic conductivity (S cm−1), l is the thickness of the sample (cm), A is the measurement area (cm), and R is total resistance (Ω).