Fig. 1. (a) Comparison of the XRD patterns between PBC-FCNCY and PBCC, (b) XRD refinement spectrum of PBC-FCNCY powder (color online)

Fig. 2. Size distribution extracted from SEM images of PBC-FCNCY (a) and PBCC (b), (c) SEM micrograph and SEM-EDS mapping of PBC-FCNCY (color online)

Fig. 3. Coefficients of thermal expansion of electrolyte YSZ, PBC-FCNCY, and PBCC at room temperature to 850 °C

Fig. 4. (a) Electrical conductivities of PBC-FCNCY and PBCC samples at 300~900 °C in the air, (b) O₂-TPD curves of PBC-FCNCZ, and PBCC powders tested from 100~700 °C (color online)

Fig. 5. EIS of a single cell with a PBC-FCNCY (a), PBCC (b) electrode measured at 550~700 ℃, (c) DRT diagram of two electrodes based on full cell at 700 ℃ (color online)

Fig. 6. IVP of a single cell with PBC-FCNCY (a) and PBCC (b) air electrode measured in air at 550~700 ℃, typical I-V curves for cells with PBC-FCNCY (c) and PBCC (d) air electrodes measured in electrolysis mode at 550~700 ℃ with humidified H₂ (30% H₂O) in the fuel electrode and ambient air in the air electrode (color online)

Fig. 7. (a) Stability test of a single cell using PBC-FCNCY as electrode materials at 650 ℃ and a constant current density of 0.5 A·cm^-2 (FC mode), (b) Reversible cycling operation of the single cell at a current density of ±0.5 A cm^-2 at 650 ℃, when the operating mode was switched at an interval of about 2 h between the FC and EC modes