A self-assembled hybrid electrode for reversible symmetrical solid oxide cells

Reversible Symmetrical Solid Oxide Cell (RSSOC) is a promising energy storage and conversion device with simplified cell configuration and enhanced reliability. However, the compromised activity of the electrodes in reducing and oxidizing atmospheres has restrained the overall performance of RSSOC. In this study, a multifunctional oxide Sr2FeMo0.65Ni0.35O6-δ-Gd0.1Ce0.9O2-δ (SFMN-GDC) developed by a self-assembly method is investigated as the hybrid-electrode to enhance the performance of RSSOC for the first time. The performance of the SFMN-GDC electrode is significantly enhanced with the homogeneous microstructure and extended TPBs length. Moreover, the in situ exsolved Fe-Ni alloy nanoparticle anchored on the SFMN skeleton can further enhance the electrode performance. In SOFC mode operated with H2, the RSSOC with the SFMN-GDC electrode shows a promising peak power density of 0.507 W·cm−2 at 800 °C, while in SOEC mode with 50%CO2–50%H2 at 1.5 V, a current density of 0.803 A·cm−2 is obtained. Most importantly, the RSSOC with SFMN-GDC electrode exhibits excellent stability and cycling reversible operation in both SOFC and SOEC modes for 215 h.