Entropy-driven order-to-disorder transition in perovskite anodes for high-performance solid oxide fuel cells

Solid oxide fuel cells (SOFCs) enable direct and efficient conversion of transportable hydrocarbons into electricity, offering a scalable pathway for carbon-neutral energy systems. A critical challenge in SOFC development lies in the atomic-scale structural regulation of perovskite-type anodes, which is essential for enhancing hydrocarbon oxidation kinetics while mitigating carbon deposition issues. To overcome this fundamental limitation, we propose an entropy-driven strategy to induce order-to-disorder transitions in perovskite oxides. This strategy is demonstrated in the layered ordered perovskite PrBaFe₂O_5+δ, where the introduction of five equimolar rare-earth cations at the Pr site results in the formation of a disordered A-site high-entropy perovskite anode with the composition La_0.2Pr_0.2Sm_0.2Gd_0.2Y_0.2BaFe₂O_5+δ (HEP). Such atomic-scale order-to-disorder transitions facilitate oxygen vacancy formation and improve anode hydration capacity, thereby accelerating both hydrocarbon steam reforming and carbon elimination processes. The designed HEP anode exhibits a peak power density of 774.53 mW·cm^-2 and stability over 1000 hours under wet methane (3 vol% H₂O) at 700 °C. The present work contributes a new strategy for controlling ion ordering in perovskite oxides, addressing key challenges in SOFC operating with hydrocarbon fuels.