Performance Stabilization of Reformate-Fueled, Low-Temperature Solid Oxide Fuel Cells with Ni-SDC Thin-Film Anode by Water Bubbling

Dry reformate and wet reformate operations of solid oxide fuel cells (SOFCs) with 200 nm-thick, Ni-samarium-doped ceria (SDC) anode are investigated through their electrochemical performance characteristics at 500^oC. The initial peak power density of SOFC fueled with wet reformate (composed of H₂ 75%, CO 10%, CO₂ 10%, and CH₄ 5%) humidified by water bubbling at room temperature is 34% higher than that of SOFC fueled with H₂, which is 68% higher than that of SOFC fueled with dry reformate. By alternating current impedance spectroscopy analysis, it is evaluated that wet reformate operation provides remarkably lower activation resistance and higher ohmic resistance than dry reformate operation. The power performance of SOFC fueled with dry reformate continues to decline; on the other hand, the power performance of SOFC fueled with wet reformate is stabilized after 35 hours due to the limitation of carbon poisoning of Ni-SDC thin-film anode. Actually, wet reformate operation provides 73% lower C to Ni atomic ratio than dry reformate operation.