Impact of cofiring ceria in Ni/YSZ SOFC anodes for operation with syngas and n-butane

This study explores cofiring ceria (CeO ₂) with NiO and 8 mol% yttria-stabilized zirconia (YSZ) to form Ni-based cermet anodes for high-temperature solid oxide fuel cells (SOFCs) operating on syngas and n-butane/steam fuel feeds. Particular attention is paid to the suppression of carbon deposit growth in Ni-based anodes with carbonaceous fuel feeds. CeO ₂ was cofired with NiO and YSZ to form a porous Ni cermet anode support layer after reduction in H ₂ at 800°C. The porous anode support layer (1 mm thick) was combined with a Ni/YSZ functional layer (∼25 μm thick), a dense YSZ electrolyte (10-20 μm thick), and porous La _0.8Sr _0.2MnO _3-x (LSM)/YSZ cathodes (∼50 μm thick) to form anode-supported button cells for electrochemical characterization. The button cells were tested from 700°C to 800°C on various fuels including syngas and n-butane/H ₂O mixtures at steam-to-carbon (S/C) ratios of 1.0 and 1.5. Electrochemical testing revealed that CeO ₂ addition provided stable performance at 800°C without compromising power densities-up to 0.6 W/cm ² on syngas and 0.35 W/cm ² on direct butane feeds. Furthermore, the addition of CeO ₂ suppressed significant carbon deposition as observed for Ni/YSZ anode support layers without CeO ₂. Testing with syngas at different H ₂ and CO partial pressures indicated that high power densities can be maintained along an anode channel for up to 50% fuel conversion. The results indicate that cofiring CeO ₂ in Ni/YSZ anode support layers presents a viable option for stable SOFC operation on either prereformed or internally reformed light-hydrocarbon fuel feeds.