Abstract

Porous La_1-xSr_xCoO_3-δ (LSC) electrodes with Sr composition x = 0.2 (LSC-82) and x = 0.4 (LSC-64) were prepared by screenprinting LSC powders onto rare-earth doped ceria electrolytes, followed by sintering at 950 ∼ 1100◦C, and characterization using scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface-area analysis, 3-D morphological imaging based on focused ion beam scanning electron microscopy (FIB-SEM), and energy dispersion X-ray spectroscopy (EDX/EDS). The batch-tobatch variability and degradation (over 1000 ∼ 2000 hours) of the electrochemical performance of these cells were studied using electrochemical impedance spectroscopy (EIS) and measurements of nonlinear electrochemical impedance (NLEIS). These measurements reveal a strong correlation between the characteristic frequency (ω_c) and characteristic resistance (R_c) of the electrodes, which, when analyzed in light of microstructural data, indicates that performance variability and degradation are caused primarily by variations in the surface rate coefficient k(T) for O₂ exchange.

# Graphical Abstract