Anion Doping Synergistic Strategy Achieving Multi‐Interfaces and Modulated Dielectric Coupling for Efficient Electromagnetic Response

Abstract Efficient microwave absorbers are needed to address the electromagnetic pollution caused by the proliferation of new radio technologies and equipment. Excellent microwave absorption performance can be achieved by controlling the dielectric constant. Heteroatom‐doped bimetallic materials are promising electromagnetic wave absorption (EMA) materials due to their tunable structures and low cost. In particular, the presence of anionic sites significantly affects their dielectric constant and electrical conductivity. Herein, a 1D carbon nanofiber material is prepared by encapsulating FeCo nanoparticles in a fiber cavity by electrostatic spinning. Subsequently, tellurization, vulcanization, and selenization processes are carried out. FeTe 2 / CoTe 2 @C exhibits stronger conductivity and dielectric loss due to the lower electronegativity of Te. The clever configuration of FeTe 2 , CoTe 2 , and C heterostructures obtained by Te doping generates multi‐heterogeneous interfaces that facilitate charge migration and enhance interfacial polarization, obtaining excellent EMA performance. FeTe 2 /CoTe 2 @C exhibits an optimum minimum reflection loss (RL min ) of −51.1 dB with a matching thickness of 2.0 mm, and the effective absorption bandwidth (EAB) reaches 4.2 GHz. Radar cross‐section (RCS) calculations show the great potential of FeTe 2 /CoTe 2 @C for practical military stealth technology. This study offers novel guidance for improving the EMA properties of transition metal matrix composites via anionic coordination modulation.