Performance of Ceria-electrolyte Solid Oxide Fuel Cell Using Simulated Biogas Mixtures as Fuel

In this study, a samarium cerium electrolyte-supported solid oxide fuel cell (SOFC) was assembled with Ce0.8Sm0.2O2−δ (SDC) electrolyte, La0.58Sr0.4Fe0.8Co0.2O3-δ (LSCF) as cathode and WNi-Ce as anode. A porous layer of SDC between anode and electrolyte was used to improve adhesion of the anode ink. The cell performance was investigated with hydrogen and three simulated biogas mixtures (CH4/CO2/H2 70/25/5, 60/35/5 and 50/45/5) on the anode and static air on the cathode at 750oC. In addition, the effect of H2S (10ppm) incorporation in the biogas on the cell performance has been examined. The electrochemical behavior of the cell has been evaluated using IV curves, impedance spectroscopy and load demands. The results revealed that the best performance was obtained with the biogas composition richer in CH4 due to probably the higher catalytic activity of WNi-Ce in this operation condition. Furthermore, the addition of H2S in biogas causes an important decrease on the cell performance owing to the sulphuration reactions of anodic material. However, the stability tests under load demands revealed that the cell does not suffer degradation under any studied operation conditions (biogas composition and H2S in the fuel). This suggests that WNi-Ce could be a suitable anode material for ceria-electrolyte SOFC direct feeding of biogas.