A Stable and Efficient Cathode for Fluorine-Containing Proton-Conducting Solid Oxide Fuel Cells.

Substitution of anions such as F and Cl can effectively improve the stability of proton-conducting electrolytes at no expense to proton conduction. However, during operation, F and Cl in electrolytes can transfer to the cathodes, which reduces the stability of the electrolytes. In this work, F -doped Ba Sr Co Fe O [Ba Sr Co Fe O F (F-BSCF)] was prepared as a potential cathode for proton-conducting solid oxide fuel cells with BaCe Sm F O electrolyte. The incorporation of F in the cathode depressed F diffusion from the electrolyte and improved the stability of button cells. Temperature-changing X-ray photoelectron spectroscopy and electronic conductivity relaxation results demonstrated that the incorporation of F enhanced the oxygen incorporation kinetics at intermediate temperatures and improved the cathode catalytic performance. Moreover, a button cell prepared with this novel cathode was stable for 270 h at a current density of 300 mA cm and 700 °C, which was much superior than those containing a BSCF cathode.