A sandwich-structured flexible carbon fiber with RGO/CoFe₂O₄ electromagnetic synergistic enhancement for efficient electromagnetic wave absorption and thermal management

Although traditional ferrite wave-absorbing materials demonstrate excellent magnetic loss capabilities, they suffer from high density, dependence on a single magnetic loss mechanism, and impedance mismatch in the high-frequency range. These factors significantly limit their application in lightweight equipment and broadband stealth technologies. Therefore, it is particularly important to combine ferrite with other materials to enhance its wave-absorbing properties and reduce the overall density of the composite.This study successfully fabricated composite films of CNF-CoFe₂O₄ (CC), CNF-RGO (CR), and CNF-(CoFe₂O₄/RGO) (CCR) using electrospinning technology, where CNF serves as the substrate loaded with magnetic CoFe₂O₄ nanoparticles and dielectric RGO. On one hand, the electrospun films, composed of high-aspect-ratio CNF and compressed into multilayered stacking configurations, enhance the effective absorption area and promote multiple reflections and interfacial effects of electromagnetic waves within the CNF matrix, contributing to conductive and polarization relaxation losses. On the other hand, the magnetic CoFe₂O₄ nanoparticles result in eddy current and resonance losses. The formulated S1 sample exhibits a minimum reflection loss (RL_min) of −38 dB and a maximum effective absorption bandwidth (EAB) of 6.4 GHz, while achieving a high thermal conductivity of 4.983 W/(m·K), thereby enhancing the material's versatility.