Synergy and Stability: The Rise of High-Entropy Single-Atom Catalysts

While single-atom catalysts (SACs) achieve nearly 100% atom utilization and provide well-defined active sites, their development is hindered by a fundamental trade-off between activity and stability. High-entropy single-atom catalysts (HESACs) address this by reconfiguring the active site from a single-metal center into a dynamic, multi-component ensemble. This strategy effectively decouples this long-standing challenge in atomically dispersed catalysts. This review explores how HESACs redefine the active site from a static, single site to a dynamic, multisite ensemble, a concept that directly addresses the limitations of conventional SACs. We first elucidate the unique stabilization mechanisms in HESACs, where high configurational entropy, severe lattice distortion, and slow diffusion synergistically immobilize single atoms and create a flexible electronic landscape. Subsequently, a system analysis of precision synthesis strategies is presented, highlighting pathways to achieve atomic-level control over complex compositions. We focus on their application in electrocatalysis and energy storage, where HESACs demonstrate enhanced performance through multisite synergy and entropy-driven stabilization. Particular emphasis on reaction-oriented design principles, structural engineering strategies, and advanced characterization, which enable a rational design of HESACs. Finally, we discuss future challenges and opportunities, positioning HESACs as a versatile materials platform showing promise for the development of next-generation electrocatalysts and energy storage materials.