Preparation and evaluation of a stable cathode material SmBa0.75Sr0.25Fe2O5+δ for solid oxide fuel cells

In this study, Sr doping SmBa _0.75 Sr _0.25 Fe ₂ O _5+δ (SBSF25) oxide for solid oxide fuel cells (SOFCs) cathode are prepared and investigated its properties. First principles calculation indicates that the oxygen vacancy formation energy of SBSF25 (1.76 eV) is lower than that of SmBaFe ₂ O _5+δ (2.49 eV). Doping Sr significantly reduces the band center energy of Fe-3d and O-2p in SBSF25. At 800 ℃, the polarization resistance (Rp) of SBSF25 on SDC and LSGM electrolyte are 0.025 Ωcm ² , and 0.018 Ωcm ² in air, respectively. While the Rp of SBF on on SDC and LSGM electrolyte are 0.064Ωcm ² , and 0.046Ωcm ² in air, respectively. At 800 ℃, using H ₂ as fuel, the maximum power density (MPD) of fuel cell with SBSF25, SBF as cathode reaches 758.6 mW/cm ² and 670.2mW/cm ² , respectively. Sr doping SBF significantly improves the Rp stability in air and containing CO ₂ atmosphere. This results indicated that SBSF has good electrochemical performance and stability as intermediate temperature SOFCs cathode.