Evaluation of electrochemical performance and carbon deposition behaviour of Sn, Ag, Cu, Fe-doped Ni/ScCeSZ anode solid oxide fuel cells operated with simulated biogas

The infiltration of Sn, Ag, Cu, and Fe dopants into a Ni/ScCeSZ anode was investigated to enhance its catalytic activity towards methane dry reforming and improve the carbon resistance of Ni-based anode solid oxide fuel cells (SOFCs). The electrochemical performance of the modified SOFCs was evaluated under hydrogen and simulated biogas at 750 °C. Among all the tested cells, the Sn-doped cell exhibited the highest power output, with peak power densities of 0.997 W•cm⁻² and 0.963 W•cm⁻², respectively. The undoped Ni/ScCeSZ anode ceased operation after 11 h of exposure to biogas at 750 °C due to severe carbon deposition. In contrast, all doped cells operated successfully for over 120 h under simulated biogas. SEM and Raman spectroscopy characterisation confirmed that no carbon deposition occurred on the surfaces of the Sn, Ag, and Cu-doped anodes during biogas operation. Despite carbon deposition being detected on both undoped and Fe-doped anodes after biogas operation, the infiltration of the Fe dopant resulted in a reduced degree of graphitisation of the carbon deposited on the biogas-tested anode surface.