Influence mechanisms and coping strategies of impurities on biogas solid oxide fuel cells

As an emerging approach for biomass energy valorization, solid oxide fuel cells (SOFCs) technology enables the in-situ conversion of biogas into syngas rich in hydrogen, which can subsequently be converted into high-quality electrical power through electrochemical pathways. However, owing to the diverse sources of biogas, it inevitably contains trace impurities such as sulfides, chlorides, and siloxanes. The fact that SOFCs’ performance and longevity are drastically undermined by these impurities, even at very low concentrations, remains a primary obstacle hindering the widespread development of biogas-fueled SOFC systems. Therefore, elucidating the degradation mechanisms of biogas contaminants and investigating corresponding solutions are prerequisite steps for the successful deployment of biogas SOFCs. In this review, the degradation mechanisms and the corresponding countermeasures of the main impurities (sulfides, chlorides, and siloxanes) on SOFCs are systematically summarized, and the current challenges and future development directions of biogas SOFCs are discussed. In summary, for SOFCs operating on biogas, anode poisoning can be mitigated by upstream gas purification, optimizing operating conditions and cell configuration, modifying the existing anodes, or developing new anode materials.