The influence of sintering condition on microstructure, phase composition, and electrochemical performance of the scandia-ceria-Co-doped zirconia for SOFCs

Abstract

Samples of 6 mol%Sc2O3 ? 1 mol% CeO2 co ? doped ZrO2 were fabricated by conventional ceramic processing methods and sintered at various temperatures from 1000?C to 1650?C in air. The sintering conditions on microstructure and phase content are investigated using various characterization methods, including pycnometry, diffraction, and spectroscopy. The electrical conductivity of samples was investigated using electrochemical impedance spectroscopy (EIS). The effect of inductive load (measured from room temperature to 800?C) is discussed in low to high temperature regimes. At T < 400?C since the arc is not a complete semicircle, the high-frequency arc could be fit using a constant phase element (CPE), while by subtraction of inductive load, a good fit is achieved using a capacitor element instead of CPE. The Arrhenius conductivity plot of samples reveals that the specimen sintered at 1600?C for 6 hours exhibits the highest conductivity. The activation energy (Ea) and conductivity pre-exponential (??0) factor are calculated from a linear fit to data that decreases by the increase in sintering temperature.