Sulfur-Tolerant Hierarchically Porous Ceramic Anode-Supported Solid-Oxide Fuel Cells with Self-Precipitated Nanocatalyst

Abstract

A hierarchically porous Sr 2 Fe 1.5 Mo 0.5 O 6-δ -Gd 0.1 Ce 0.9 O 1.95 (SFM-GDC) ceramic anode-supported solid-oxide fuel cell with a GDC electrolyte film was fabricated by freeze-drying tape-casting and drop coating. 3D X-ray computed tomography analysis indicated that the SFM-GDC anode has a high porosity and low tortuosity factor, facilitating gas diffusion in the anode during fuel cell operation. Peak power density of cells with a La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 -GDC (LSCF-GDC) cathode can reach 0.22Wcm -2 at 700°C when using H 2 as the fuel and ambient air as the oxidant. The SFM-GDC anode shows excellent sulfur tolerance when using H 2 with 50ppm H 2 S. SEM analysis demonstrates that the nanocatalyst (iron) can precipitate from the parent SFM phase upon reduction and iron nanoparticles can react with sulfur species to form needle-like nanosulfide. Both the nanocatalyst and sulfide show a graded distribution along the thickness direction, owing to a graded local oxygen chemical potential within the anode.