A-Site High-Entropy Perovskite Enabling Sulfur-Tolerant and Coking-Resistant Anodes for Hydrocarbon-Fueled Solid...

Solid oxide fuel cells (SOFCs) are capable of electrochemically converting fossil fuels such as natural gas and coal-based syngas directly into electricity with high efficiency and minimal emissions, yet the state-of-the-art nickel-based anodes are susceptible to sulfur poisoning or coking when operated with sulfur-containing or hydrocarbon fuels. Here, we report a high-entropy strategy in which five equimolar cations are introduced at the A-site to develop a highly active and robust perovskite anode, Pr_0.2Ba_0.2La_0.2Sr_0.2Ca_0.2FeO_3-δ (PBLSCF). In situ reduction of PBLSCF leads to the exsolution of nanoscale Fe particles, enhancing its tolerance to sulfur poisoning and coking. Electrolyte-supported single cells using PBLSCF anodes achieve a peak power density (PPD) of 1.22 W cm^-2 at 800°C in H₂, maintain stable operation for 1000 h and exhibit promising sulfur tolerance in 50 ppm H₂S-H₂. Density functional theory (DFT) calculations reveal that the high-entropy strategy reduces oxygen-vacancy formation energy, contributing to improved sulfur tolerance and fuel oxidation performance. Furthermore, stable operation using a PBLSCF anode for 600 h is also achieved with propane as fuel. This work provides a synergistic strategy through A-site high-entropy engineering and in situ metal exsolution to achieve promising electrochemical performance and enhanced multi-tolerance anodes for fuel-flexible SOFCs.