Use of Novel Dopants on Solid Oxide Fuel Cell Anodes to Reduce Carbon Deposition and Improve Sulfur Tolerance

The use of biogas within a solid oxide fuel cell has a number of advantages but poses difficulties in the form of carbon deposition and sulfur poisoning of the anode. As many gas clean-up technologies add large expense to a fuel cell system, thus reducing marketability, this study aims to improve the tolerance of solid oxide fuel cells to these forms of degradation through anode infiltration. Molybdenum and tungsten are commonly used in industrial applications of hydrodesulfurisation and therefore indicate potential for use in solid oxide fuel cell anodes in order to limit the degradation through operation on sulfur-contaminated biogas. Ammonium molybdate tetrahydrate ((NH4)6Mo7O24 • 4H2O), ammonium tetrathiomolybdate ((NH4)2MoS4), ammonium tungstate pentahydrate ((NH4)10W12O42 • 5H2O) and ammonium tetrathiotungstate ((NH4)2WS4) have been used to prepare solutions with which to infiltrate the anodes of Ni/YSZYSZ LSM solid oxide fuel cells. The effects on the rate of deterioration and the microstructure of the anode were studied both electrochemically and qualitatively through Scanning Electron Microscopy (SEM).