Coherent Single‐Atom Dipole–Dipole Coupling Mediates Holistic Regulation of K⁺ Migration for Superior Energy Storage and Dendrite‐Free Metal Deposition

Abstract Potassium‐based batteries, including potassium‐ion (PIBs) and potassium metal batteries (PMBs), are gaining attention as alternatives to lithium‐ion batteries (LIBs). However, potassium's large ionic radius (1.38 Å) reduces charge density, weakens solvation, and increases energy barriers for K + diffusion, leading to slower reaction kinetics, thicker solid electrolyte interphase (SEI) layers, and dendrite formation. To address these challenges, a novel single‐atom Fe‐N 4 dipole–dipole coupling (SA.Fe) is proposed. The unique Fe‐N 4 coordination and highly conductive Ketjen black (KB) substrate establish a rapid horizontal electron transfer network, enhancing electrode interface reactions. Moreover, Fe‐N‐C coordination generates a short‐range polar electric field, improving K + affinity and diffusion. This coherent single‐atom coupling effectively regulates K + migration, significantly enhancing reaction kinetics and lowering diffusion barriers. The SA.Fe anode delivers high reversible capacities (446.3 mAh g −1 ) and exceptional durability (10 000 cycles at 2.0 A g −1 ) in PIBs, alongside remarkable stability (600 cycles at 0.5 mA cm −2 ) and fast potassium metal (K metal) deposition without dendrite formation in PMBs. This study highlights the potential of coherent single‐atom dipole coupling for efficient K + storage and dendrite‐free batteries, offering a promising pathway for next‐generation potassium‐based energy systems.