Impregnation of La0.4Ce0.6O1.8-La0.4Sr0.6TiO3 as solid oxide fuel cell anode in H2S-containing fuels

Active anodes were fabricated via wet chemical impregnation of optimized amount of La0.4Sr0.6TiO3 (L4ST) into La0.4Ce0.6O1.8 (LDC) pre-infiltrated porous yttria-stabilized zirconia (YSZ) matrix. Impregnations of 10 wt% LDC with 16 wt% L4ST significantly improved the performance of the fuel cell from 48 mW cm−2 for pure L4ST to 161 mW cm−2 for LDC-L4ST at 900 °C in H2. The contribution of the pre-loaded LDC to this improvement was investigated using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) as well as transmission electron microscopy (TEM). The measurement results indicated that pre-infiltrated LDC increased the activity of the anode more effectively by decreasing the total polarization resistance of the cell from 3.3 Ω cm2 to 1.0 Ω cm2 in humidified H2 at 900 °C. More importantly, the LDC nano-deposits (<20 nm) behaved as an effective “adhesive” that substantially enhanced the wettability of L4ST on YSZ matrix, resulting in finer and more uniform structure of L4ST infiltrates. The LDC-L4ST cells also demonstrated significantly improved performances in 0.5% H2S-H2 and 0.5% H2S-CH4 with higher stability than cells with pure L4ST anode.