A new proton conductor-derived cathode with high performance for protonic ceramic fuel cells

The proton conductor Sc-doped SrSnO3 is tuned with Fe and Co elements to provide a novel cathode for protonic ceramic fuel cells (PCFCs). The new SrFe0.4Co0.4Sn0.1Sc0.1O3-delta (SFCSS) material is successfully synthesized and demonstrated adequate chemical stability against CO2, which is preferable to traditional Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) cathodes. Although SFCSS's oxygen diffusion kinetics are inferior to those of BSCF, the proton-conductorderived design allows SFCSS to retain good proton diffusion and surface exchange abilities, which are critical in PCFC cathode reactions. As a result, in terms of fuel cell performance, SFCSS-based cathode-based fuel cells outperform BSCF-based fuel cells. A further improvement of fuel cell performance with a high peak power density of 1538 mW cm-2 at 700 degrees C is obtained for the cell using the single-phase SFCSS cathode. The SFCSS cathode's suitability for PCFCs is also demonstrated by the long-term stability test, which demonstrates that the cell can operate continuously for approximately 200 h without degradation. This study not only provides an efficient cathode for PCFCs but also an intriguing method for fabricating novel cathodes from Sc-doped SrSnO3 proton conductors.