Constructing chromium-tolerance La0.6Sr0.4Co0.2Fe0.8O3-s cathode for solid oxide fuel cells using entropy-assisted surface engineering

Commercial application of solid oxide fuel cells (SOFCs) for power generation primarily depends on the durability and catalytic activity of cathode materials. However, current Sr-based cathode materials, without exception, are seriously affected by their insufficient durability (Sr segregation) and Cr poisoning from Cr-containing steel interconnects. Here, based on CeO2, by using entropy-assisted surface engineering, (La0.2Pr0.2Nd0.2Sm0.2Gd0.2)0.2Ce0.8O2-s (HEDC) is designed as a catalyst coating on the surface of La0.6Sr0.4Co0.2Fe0.8O3-s (LSCF) to boost the oxygen reduction reaction (ORR) kinetics and Cr-tolerance of LSCF-HEDC cathode. As a result, the LSCF-HEDC cathode displays considerably improved Cr-tolerance with a slow degradation rate of 1.05 x 10-3 S2 cm2 h-1 for polarization resistance (Rp) at 800 degrees C under Cr treatment, much better than the results of LSCF (13.66 x 10-3 S2 cm2 h-1), Gd0.1Ce0.9O1.95-coated LSCF (7.36 x 10-3 S2 cm2 h-1) and Sm0.2Ce0.8O1.9-coated LSCF (5.80 x 10-3 S2 cm2 h-1). Furthermore, the synergistic effects of protection and catalysis provided by the unique high entropy surface and nanoparticles endow LSCF-HEDC cathode with exceptional durability and catalytic activity. This work provides a new scenario for solving the challenges of designing conventional catalysts, which significantly facilitates the achievement of stable high-performance cathodes in practical applications.