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초록

Single-atom catalysts (SACs) achieve the isolation of metal centers on conductive supports by the tailored coordination, which means that the atoms are used to the maximum and the electronic states are quantized uniquely. In addition to the intrinsic turnover at the active site, SACs modify interfacial fields, desolvation barriers, and ionic flux in porous electrodes. In this paper, we combine these traditionally separate views activity and transport and claim that SACs serve as dynamic bridges which at the same time regulate (i) local charge density and spin states, (ii) ion adsorption/migration through interfacial electric fields and dipoles, and (iii) device-level kinetics under realistic bias and cycling. We illustrate the influence of d-band center, oxidation state, and coordination (N, S, P, O, vacancy) on adsorption free energies and the Poisson-Nernst-Planck landscape for ions in batteries, fuel cells, supercapacitors, and electrolyzers. We provide a substantial part of operando evidence for restructuring, valence oscillations, and transient ensembles induced by bias, discuss coupling strategies with MXenes, MOF-derived carbons, and 2D conductors to co-optimize electron/ion highways, and delineate AI-guided atomic design loops. In the end, we put forward a reporting checklist that connects site density and electronic descriptors with ionic transport observables (EIS, GITT/PITT, transference number) and durability metrics. The interpretation of SACs as electronic-ionic bridges helps in understanding mechanisms and speeds up the rational designs for oxygen redox, CO2 reduction, and metal-air systems. © 2024

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