Mechanically Robust and Thermal Insulating Nanofiber Elastomer for Hydrophobic, Corrosion‐Resistant, and Flexible Multifunctional Electromagnetic Wave Absorbers

Abstract Multifunctionalization of electromagnetic wave absorbing materials (EMWAMs) presents a promising avenue for their application in complex scenarios. However, the effective integration of multiple supplementary functions into EMWAMs continues to pose a significant challenge. Herein, a novel nanofiber elastomer (NFE) incorporating multicomponent inorganic FeS 2 /S,N co‐doped carbon nanofibers (NFs) and organic component (Ecoflex) are designed and synthesized. The sulfur doping ratios and species can be effectively modulated via controlling the amount of sulfur and sulfurization temperature. The optimized FeS 2 /S,N co‐doped carbon NFs/Ecoflex NFE not only exerted an excellent impedance matching characteristic, but also displays boosted conductive loss and polarization loss capacities. Amongst, the designed NFE achieved an ultra‐wide effective absorption bandwidth (EAB) of 7.40 GHz and minimum reflection loss (RL min ) of −21.82 dB at the thin matching thickness (≈2.00 mm). Furthermore, FeS 2 /S,N co‐doped carbon NFs/Ecoflex NFE simultaneously presents greatly improved mechanical property, thermal insulation, hydrophobicity, and corrosion resistance. Through designing metastructures, the NFE with a periodically closed‐ring resonant structure realized an EAB of 32.64 GHz (ranging from 7.36 to 40.00 GHz). Overall, this research contributes valuable insights for the design of next‐generation EMWAMs with satisfactory multifunctionalities, demonstrating their significant potential for application in smart devices and challenging environments.