Tailoring Sr2Fe1.5MO0.5O6-δ with Sc as a new single-phase cathode for proton-conducting solid oxide fuel cells

Sc-doped Sr2Fe1.5MO0.5O6-delta (SFMSc) was successfully synthesized by partially substituting Mo in Sr2Fe1.5MO0.5O6-delta (SFM) with Sc, resulting in a higher proton diffusion rate in the resultant SFMSc sample. Theoretical calculations showed that doping Sc into SFM lowered the oxygen vacancy formation energy, reduced the energy barrier for proton migration in the oxide, and increased the catalytic activity for oxygen reduction reaction. Next, a proton-conducting solid oxide fuel cell (H-SOFC) with a single-phase SFMSc cathode demonstrated significantly higher cell performance than that of cell based on an Sc-free SFM cathode, achieving 1258 mW cm(-2) at 700 degrees C. The performance also outperformed that of many other H-SOFCs based on single-phase cobalt-free cathodes. Furthermore, no trade-off between fuel cell performance and material stability was observed. The SFMSc material demonstrated good stability in both the CO2-containing atmosphere and the fuel cell application. The combination of high performance and outstanding stability suggests that SFMSc is an excellent cathode material for H-SOFCs.

Automated summary

Sc-doped Sr2Fe1.5MO0.5O6-delta shows improved proton diffusion rate, reduced vacancy formation energy and increased catalytic activity. The H-SOFC based on SFMSc cathode exhibits excellent performance and stability.