Micro‐/Nanohoneycomb Solid Oxide Electrolysis Cell Anodes with Ultralarge Current Tolerance

Abstract As a clean, efficient, and promising energy conversion device, solid oxide electrolysis cell (SOEC), which can achieve transformation from electricity to chemical fuels, has captured worldwide attention. A novel biomimetic honeycomb SOEC anode with super low tortuosity factor (≈1), ground‐breaking porosity (≈75%), and high structural strength, has been successfully fabricated by freeze casting and infiltrating. This honeycomb anode demonstrates ultralow polarization resistance (0.0094 Ω cm 2 , lower than any existing anodes reported so far) and high durability for hours at a large current density of 2.0 A cm −2 at 800 °C. These unique advantages are derived from the effective release of oxygen through the yttria‐stabilized zirconia honeycomb skeletons, and the exposure of active areas along the inner pore of the honeycomb structure after infiltrating La 0.6 Sr 0.4 CoO 3± δ . Such a honeycomb electrode combines high electrical, chemical, and thermal stability under high temperatures and large current densities, demonstrating the feasibility of biomimetic structures for use in large‐scale and highly efficient energy conversion systems.