High-Entropy Single Atom Catalysts Anchored on Flexible Carbon Fibers for Enhanced Bifunctional Oxygen Catalysis Activity and Stability

High-entropy single atom (SA) catalysts (HESACs) represent a paradigm shift in electrocatalyst design, yet precise structural control and mechanistic understanding remain key challenges. Here, we report a porous carbon fiber-supported HESAC (ZnCoNiCuFe@PCF) that synergistically integrates five atomically dispersed M-N₄ sites (M = Zn, Co, Ni, Cu, Fe) and Co₆/Fe₅ nanoclusters, creating unprecedented electronic interactions and maximizing high-entropy synergy. As a result, ZnCoNiCuFe@PCF exhibits outstanding bifunctional electrocatalytic activity for both oxygen reduction (oxygen reduction reaction (ORR)) and oxygen evolution reactions (OER), outperforming the benchmark Pt/C and RuO₂ catalysts. Density functional theory calculations reveal that the unique combination of high-entropy atom sites and nanoclusters facilitates charge redistribution and optimizes the adsorption of key intermediates (OH*, O*), thereby accelerating the rate-limiting steps of ORR/OER. When deployed as the cathode in a zinc-air battery (ZAB), the catalyst delivers a peak power density of 240.9 mW cm^-2 and exceptional cycling stability of over 2600 h (7800 cycles). This work provides fundamental insights into the rational design of HESACs by leveraging high-entropy and heterojunction effects, offering a robust platform for next-generation energy storage and conversion technologies.