High-Entropy Alloys FeCoNiCuX (X = Al, Mo)-Ce_0.8Sm_0.2O₂ as High-Performance Solid Oxide Fuel Cell Anodes

High-entropy alloys (HEAs) have received a lot of attention in electrocatalysis due to their potent synergistic effects of uniformly mixing many elements. In this study, HEAs FeCoNiCuX (X = Al, Mo)-Ce0.8Sm0.2O2 (SDC) are considered as a prospective intermediate temperature solid oxide fuel cell (SOFC) anode. FeCoNiCuX-SDC as a SOFC anode shows comparable high conductivity with a Ni-based anode and exhibits outstanding catalytic capability for H2, CH4, and CO2. The LSGM electrolyte-supported single cell with FeCoNiCuAl-SDC as anode shows maximum power densities of 779 and 526 mW cm–2 with H2 and CH4 as fuel gases and testing at 850 °C, respectively. The distribution of relaxation time analysis shows that the prime speed-limiting steps for the FeCoNiCuX-SDC anode are the adsorption/dissociation of fuel gas. X-ray photoelectron spectroscopy results showed that FeCoNiCuX HEAs with the main constituents in different valence states created more active sites, which provided a synergistic effect for H2, CH4, and CO2 catalysis.