Assessment of cobalt-free ferrite-based perovskite Ln0.5Sr0.5Fe0.9Mo0.1O3-δ (Ln = lanthanide) as cathodes for IT-SOFCs

Cobalt-free perovskites Ln(0.5)Sr(0.5)Fe(0.9)Mo(0.1)O(3-delta) (Ln = lanthanide; LnSFM) were prepared via a sol-gel process. Pure rhombohedral phases were still not obtained for the samples (Ln = Sm and Gd) even sintered at 1300 degrees C. Thus, only the LaSFM, PrSFM and NdSFM compositions were assessed as IT-SOFC cathodes in terms of their thermal, electrical and electrochemical properties. Thermal expansion of the LnSFM was well compatible with that of Sm0.2Ce0.8O1.9 (SDC) electrolyte. Both conductivity and electrochemical performances of the LnSFM followed the same sequence of La > Nd > Pr. For the LaSFM, NdSFM and PrSFM cathodes, peak conductivities reached 73, 63 and 59 S.cm(-1) at 650 degrees C; polarization resistances attained 0.211, 0.446 and 0.469 omega.cm(2) at 700 degrees C; peak power densities of the LnSFM cells with 300-mu m-thick SDC electrolyte achieved 269, 261 and 233 mW.cm(-2) at 700 degrees C without cell degradation for operating 100 h. By comprehensive comparison, the LaSFM is assessed as a preferred cobalt-free ceramic cathode for IT-SOFC.

Automated summary

The cobalt-free perovskite Ln(0.5)Sr(0.5)Fe(0.9)Mo(0.1)O(3-delta) was prepared via a sol-gel process, with LaSFM being assessed as the preferred ceramic cathode for IT-SOFC based on its excellent performance.