Recent progress in metal-ceramic anode of solid oxide fuel cell for direct hydrocarbon fuel utilization: A review

Solid oxide fuel cell (SOFC) has been popular as an alternative method for generating electricity from hydrocarbon fuels like methane. This article critically evaluates carbon deposition problem encountered by hydrocarbon fuelled SOFC, carbon detection method and recent progress in the applications of cermet material as anode to mitigate the carbon deposition. Recently researchers have diverged from using conventional Ni-YSZ cermet material to alloying metals such as Ni, Cu, Zn, Fe, Co, Mo, Sn, W and Sb, coupled with ceramic oxygen conductors like doped zirconia, doped ceria, and perovskite-related materials such as doped promethium barium manganite (PBMO). Due to their reforming catalytic ability, Pt group metals gave outstanding carbon deposition tolerance, while Ni, Co and Fe alloys often result in carbon deposition. Single and alloy of metals yield different tolerance level such as those of Ni-ceramic and Ni-M-ceramic (M = metal). Fabrication methods are crucial in producing alloy. For example, despite of being non-reducible by hydrogen, certain metal oxides such as Zn in NiZn is reducible in alloy form, while other like Co are not. For future direction, we recommend both alloying and combining the ceramic component with mixing oxygen carrier that contain perovskite to enhance the carbon deposition tolerance of SOFC.