Ba0.9Co0.5Fe0.4Nb0.1O3-5 as novel oxygen electrode for solid oxide electrolysis cells

摘要

A novel perovskite oxide Ba0.9Co0.5Fe0.4Nb0.103-8 (BCFN) was prepared and characterized as oxygen electrode for solid oxide electrolysis cells (SOECs) using La0.8Sr0.2-Ga0.83Mg0.27O(_3-5) (LSGM) as electrolyte. Symmetrical half-cell study shows that the polarization resistance of BCFN is only 0.08 Ω cm~2 at 750 °C in air. Electrochemical impedance spectra and voltage-current curves of the electrolysis cell with the configuration of BCFNILSGMILa(_0.4)Ceo.6O2-xlNi-Ce0.9Gd0.1O_1 95 were measured as a function of operating temperature and steam concentrations to characterize the electrolysis cell performances. Under an applied electrolysis voltage of 1.5 V, the maximum consumed current density increased from 0.835 A cm"2 at 700 °C to 3.237 A cm"2 at 850 °C with 40 vol.% absolute humidity (AH), and the hydrogen generation rate of the cell can be up to 1352 mL cm~(-2) h(~-2) with 40 vol.% AH at 850 °C. Further, the electrolysis cell has showed very stable performance during a 200 h short-term electrolysis testing, indicating that BCFN can be a very promising candidate for the oxygen electrode of SOECs using LSGM electrolyte.