Excellent Electrochemical Performance of La0.3Sr0.7Fe0.9Ti0.1O3-δ as a Symmetric Electrode for Solid Oxide Cells.

Abstract

Solid oxide cells (SOCs) can switch between fuel cell and electrolysis cell modes, which alleviate environmental and energy problems. In this study, the La0.3Sr0.7Fe0.9Ti0.1O3-δ (LSFTi 91) perovskite is innovatively used as a symmetric electrode for solid oxide electrolysis cells (SOECs) and solid oxide fuel cells (SOFCs). LSFTi 91 exhibits a pure perovskite phase in both oxidizing and reducing atmospheres, and the maximum conductivity in air and 5% H2/Ar is 150 and 1.1 S cm-1, respectively, which meets the requirement of the symmetric electrode. The polarization resistance (Rp) at 1.5 V is as low as 0.09 Ω cm2 in the SOEC mode due to the excellent CO2 adsorption capacity. The current density can reach 1.9 A cm-2 at 1.5 V and 800 °C, which is the highest electrolytic performance in the reported single-phase electrodes. LSFTi 91 also exhibits eminent oxygen reduction reaction and hydrogen oxidation reaction (ORR and HOR) activities, with Rp of 0.022 and 0.15 Ω cm2 in air and wet H2, respectively. The peak power density of SOFC could reach 847 mW cm-2 at 800 °C. In addition, good reversibility is confirmed in the cyclic operation of SOFC and SOEC.