A novel catalytic layer material for direct dry methane solid oxide fuel cell

• La0.75Sr0.25Cr0.5−xFexMn0.5O3−δ nano-powders are synthesized by sol–gel process.
• The maximum content of Fe doping is 0.2.
• The materials show excellent chemical compatibility with YSZ.
• The power density of the cell obtained in methane is comparative to that in hydrogen.
• The sample sintered at 1300 °C exhibits higher electrochemical performance.

The perovskite structured oxide La0.75Sr0.25Cr0.5−xFexMn0.5O3−δ (LSCFMx, x = 0.05, 0.1, 0.15, 0.2, 0.25) powder is prepared by the liquid phase method, using iron as dopant to replace the chromium. According to XRD patterns, perovskite-like LSCFMx are stable in pure H2, except for LSCFM0.25. Thus the maximum content of Fe doping is 0.2. The calculated lattice volume increases along with the content of iron and the powders show excellent chemical compatibility with yttria-stabilized zirconia (YSZ). The electrical conductivities for LSCFM0.15 and LSCFM0.2 are very comparative, and they exhibit similar performance as catalytic materials. In contrast, the different sintered temperature with the LSCFM0.2 catalytic layer, at 1300 °C exhibits higher electrochemical performance. When dry methane is used as the fuel, the ohmic resistance and polarization resistance are 0.15 and 0.55 Ω cm2, respectively, and the power density reaches 550 mW cm−2.