An Active and Contaminants-Tolerant High-Entropy Electrode for Ceramic Fuel Cells

Intermediate-temperature ceramic fuel cells are attractive for clean and efficient energy conversion. Their commercialization, however, is primarily impeded by insufficient electrode electrocatalytic activity for the oxygen reduction reaction (ORR) and poor tolerance against contaminants. Here we report our design of a layered high-entropy electrode, Pr_0.2Sm_0.2Nd_0.2Gd_0.2La_0.2BaCo₂O_5+δ (PSNGLBC), for fast and durable ORR. When it is used as an electrode on ceramic fuel cells, a low area-specific resistance of 0.010 Ω cm² and an impressive maximum power density of 2.03 W cm^-2 are achieved at 800 °C. When Cr contamination is introduced, the high-entropy PSNGLBC electrode shows a dramatically enhanced durability compared to the PrBaCo₂O_5+δ electrode. The improved ORR activity and stability and contaminants tolerance of the PSNGLBC electrode may be attributed to the synergistic enhancement of entropy-dominated stabilization effect and lattice distortion, significantly enhancing the electrocatalytic activity and promoting the formation of a stable crystal morphology and phase structure.