Kirkendall effect‐assisted electrospinning porous FeCo/Zn@C nanofibers featuring well‐dispersed FeCo nanoparticles for ultra‐wide electromagnetic wave absorption

Abstract Ultra‐wide absorption band and flexibility are needed in multi‐scenario applications, however, current electromagnetic wave absorption materials (EMWAMs) are not capable enough to deliver due to rigid structure. Here, we have designed a porous flexible mat composed of Zn‐doped carbon (Zn@C) nanofibers (NFs) having encapsulated uniformly dispersed FeCo nanoparticles (NPs) (FeCo/Zn@C) as ultra‐wideband absorber. During the electrospinning, the Fe 3+ , Co 2+ and Zn 2+ are uniformly immobilized within the NFs nanocrystallization process. Subsequently, the Kirkendall effect is deployed to trigger the generation of FeCo NPs and porous framework under thermal annealing. The FeCo/Zn@C NFs effectively favor magnetic‐dielectric synergies due to the coexistence of magnetic FeCo NPs and dielectric carbon components. One‐dimensional porous fiber prolongs the attenuation path and enhances multi‐scattering and reflection. While the FeCo NPs encapsulated in Zn‐doped carbon NFs provide abundant dipole and interfacial polarization. These favorable factors synergistically enhance absorption performance, resulting in a reflection loss value of − 71.58 dB. Moreover, by varying the thickness of absorbers, effective absorption bandwidth spans from 4.26 to 18.00 GHz. Hence, this work offers innovative insights for fabricating advanced EMWAMs.