Robust Cathode for Efficient CO₂ Electrolysis Driven by Entropy Engineering in Solid Oxide Electrolysis Cells

Herein, we introduce an innovative approach of entropy engineering to design high-performance and durable electrodes. A series of perovskite oxides with varying configurational entropy (S_config) based on Pr_1/2Ba_1/2FeO_3−δ (PBF) matrix are synthesized, and their physicochemical properties and electrochemical performances in CO₂ reduction reaction process are explored via manipulating S_config. Notably, a high-entropy perovskite, Pr_1/6La_1/6Sm_1/6Ba_1/6Sr_1/6Ca_1/6FeO_3−δ (PLSBSCF), with an S_config of 1.79 R, exhibits significant lattice distortion due to homogeneous distributed A-site elements. It demonstrates a high concentration of oxygen vacancies, good CO₂ adsorption capability, and rapid O^2-/e^- conductions. Compared to bare PBF perovskite, PLSBSCF offers a greater number of active sites for CO₂RR, and the corresponding cell achieves remarkably high current densities of 2.86 A cm^-2 at 850 °C (1.5 V) during direct CO₂ electrolysis, while maintaining good thermal stability and operational durability. Density Functional Theory calculations also confirm the good CO₂ reduction activity of PLSBSCF perovskite.