High performance micro-monolithic reversible solid oxide electrochemical reactor

Abstract Reversible solid oxide electrochemical reactors should work efficiently in both fuel cell and electrolysis modes in order to be considered a practical technology for the energy field. In addition to improved performance, excellent electrode reversibility and stability for long-term operation are crucial for such reactors. Herein, high-performance 6-channel solid oxide electrochemical reactors for reversible operation has been successfully developed using a phase-inversion and sintering method. A unique morphology has been obtained where micro-channels were formed from multiple directions and the interchangeable thickness of sponge-like region between each channel and the exterior surface. Such micro-structured cells, which is made from commercially-available materials Ni-YSZ|YSZ|YSZ-LSM, exhibit superior performance for hydrogen (H2) fuel cell achieving 1.62 W cm−2 at 800 °C. Similarly, excellent performance for carbon dioxide (CO2) electrolysis has been demonstrated, achieving current densities up to 6.3 (3.1) A cm−2 under 1.8 (1.5) V at 800 °C. To our knowledge, such high performances are one of the highest reported values for both H2-fuel cell and CO2 electrolysis. This outstanding performance, coupled with superior mechanical robustness, promises a long-awaited alternative to the conventional tubular counterpart that would allow miniaturized system to be commercially applied in the near future.