Ru/Samaria-doped ceria gradient cermet anode for direct-methane solid oxide fuel cell

Direct methane-fueled solid oxide fuel cells (DM-SOFCs) are promising next-generation energy conversion devices, in which, however, anode reactions should be facilitated for high performance even at low temperature. Herein, we report on compositional gradient cermet anode for DM-SOFCs operated at 450 °C using co-sputtering method. The cell with the gradient cermet anode demonstrates approximately 0.1 V higher open-circuit voltage and 36% better power density than the cell with homogeneous one. Moreover, the thermal stability of the cell with the gradient cermet anode (3.7% h−1 at 450 °C) is improved compared to the cell with homogeneous one (4.5% h−1). Higher coking resistance is also observed in the cell with the gradient cermet anode with low carbon content after operation. The combination of high triple phase boundary density preserved well at elevated temperature and percolating ceria network may be the reason for such improvements in the cell with the gradient cermet anode.