Graphite Wrapped FeNi3/Co with Carbon Nanotubes Anchored on MgO@Carbon Fiber Reinforcements via Continuous Fabrication for High-Efficiency Microwave Attenuation

Carbon fiber (CF) has emerged as a promising candidate for microwave absorbers to resolve the escalating electromagnetic wave (EMW) pollution issue, not just serving as a structural reinforcement. However, the drawbacks, such as high conductivity, limit its ability to strongly absorb EMWs over a wide bandwidth. To address these challenges, graphite wrapped FeNi₃/Co with carbon nanotubes (CNTs) anchored on MgO@CF heterostructures were synthesized by introducing MgO nanofilms on a CF surface and subsequent chemical vapor deposition catalyzed by two-phase catalysts. The synthesis of MgO suppresses the etching of CF during the experimental processes, effectively maintaining the inherent structure of CF, which is conducive to constructing rich conductive networks and developing excellent mechanical properties. By modulating the catalyst concentration, deposited CNTs with appropriate defects increase the conduction loss and stimulate defect polarization loss. The abundant interfaces formed by multiple components lead to fulfilling interface polarization, while the doping of O heteroatoms causes dipole polarization. In addition, the introduction of FeNi₃/Co generates effective magnetic loss and optimizes electromagnetic parameters to form more matching impedance conditions. At a low filler loading of 23 wt%, the stable sample obtains a remarkable minimum reflection loss of up to − 72.08 dB at merely 1.38 mm with an effective absorption bandwidth reaching 4.88 GHz at only 1.44 mm, which is superior to that of numerous distinguished carbon-based composites in regard to being “thin, light, wide and strong”. CST simulation reveals that the maximum radar cross section reduction acquires 26.88 dBm², ascertaining the radar stealth capability of the distinctive heterostructure. Moreover, great mechanical and electromagnetic interference shielding performance is demonstrated by epoxy composites. Henceforth, this study proposes profound insights into the intricate relationship between the structure and EMW absorbing mechanism, and elucidates an attractive strategy for mass-producing modified CF-based hybrids for versatile applications.

Graphical Abstract