Density‐Induced Proximity Electronic Effect of Metal Single‐Atom for Multifunctional Electromagnetic Wave Absorption

Abstract The proximal electronic effect (PEE) of metal single‐atoms (M‐SAs) is crucial in tuning their physicochemical property, yet precise control over the interatomic distance between M‐SAs to optimize PEE remains challenging. Here, Ni‐SA content (1.8–7.5 wt.%) and interatomic distance between Ni‐SAs (0.85–0.27 nm) in the hierarchical porous nanofiber is modulated to deeply understand the relationship between PEE and electromagnetic wave (EMW) absorption performance. The adjustable Ni‐SA distance induces distinct PEE, in turn influence the EMW absorption properties. Experimental and theoretical results demonstrate that the strong PEE of Ni‐SAs significantly enhances the dielectric loss, leading to an effective absorption bandwidth of 6.8 GHz achieved by Ni‐SA‐based film. Additionally, the film also exhibits excellent multifunctional properties and robust environmental adaptability, highlighting its substantial practical potential. This study offers in‐depth insights into the PEE of M‐SAs on EMW absorption and a promising strategy for the design of multifunctional films.