Evolution of Solid Oxide Fuel Cells via Fast Interfacial Oxygen Crossover

While there have been significant breakthroughs in new functional cathodes facilitating the oxygen reduction reaction (ORR) for low-temperature solid oxide fuel cells (LT-SOFCs), sluggish oxygen charge transfer across the cathode/electrolyte heterogeneous interface also hinders overall performance. To promote oxygen ion exchange at the interface, a thin layer of cerium oxide decorated by an amorphous cobalt oxide overcoating was introduced to function as a fast oxygen ion transport pathway at the interface. The peak power density (PPD) of the modified cell achieved 767 mW/cm 2 at a low operation temperature of 550 °C, which is almost 3 times the power output of the unmodified cell. Oxygen isotope exchange confirmed that the oxygen reduction active cobalt oxide nanolayer drastically reduced the energy barrier for oxygen transport across the solid–solid interface. Such interface modification successfully demonstrates an effective route to enable fast ORR and oxygen transport across the cathode/electrolyte interface at low temperature.