The Effect of H2S on the Performance of SOFCs using Methane Containing Fuel

In recent years, the interest for using biogas derived from biomass as fuel in solid oxide fuel cells (SOFCs) has increased. To maximise the biogas to electrical energy output, it is important to study the effects of the main biogas components (CH4 and CO2), minor ones and traces (e.g. H2S) on performance and durability of the SOFC. Single anode-supported SOFCs with Ni–Yttria-Stabilised-Zirconia (YSZ) anodes, YSZ electrolytes and lanthanum-strontium-manganite (LSM)–YSZ cathodes have been tested with a CH4–H2O–H2 fuel mixture at open circuit voltage (OCV) and 1 A cm–2 current load (850 °C). The cell performance was monitored with electric measurements and impedance spectroscopy. At OCV 2–24 ppm H2S were added to the fuel in 24 h intervals. The reforming activity of the Ni-containing anode decreased rapidly when H2S was added to the fuel. This ultimately resulted in a lower production of fuel (H2 and CO) from CH4. Applying 1 A cm–2 current load, a maximum concentration of 7 ppm H2S was acceptable for a 24 h period.