Composition-Engineered SiC-C Hybrid Nanofibers for Broadband Electromagnetic Absorption via Tunable Dielectric-Conduction Balance

Tailoring the dielectric-conduction balance through compositional engineering provides an effective strategy for optimizing electromagnetic (EM) attenuation in ceramic-carbon hybrids. Herein, a series of SiC-C hybrid nanofibers with precisely controlled SiC:C ratios were fabricated via a one-step electrospinning-assisted carbothermal process. By varying the SiC:C mass ratio from 3:1 to 1:3, a continuous microstructural evolution was achieved—from SiC-dominated dense frameworks to carbon-enriched porous networks—enabling tunable interfacial polarization and charge transport. Structural and electromagnetic analyses reveal that the equimass composition (SiC:C = 1:1) establishes a balanced dielectric-conductive state, where abundant SiC/C heterointerfaces promote dipolar relaxation and Maxwell-Wagner polarization while moderate conductivity preserves impedance compatibility. Consequently, the optimized hybrid exhibits a minimum reflection loss (RL m ᵢ n ) of −47.7 dB and a broad effective absorption bandwidth (EAB max ) of 7.6 GHz at 2.1 mm thickness. Radar cross-section (RCS) simulations further demonstrate enhanced omnidirectional scattering suppression. A comprehensive energy dissipation mechanism correlates impedance matching, interfacial polarization, controlled conduction, and multiple internal reflections within hierarchical SiC-C networks. This study establishes a clear composition-structure-property relationship and presents a generalizable dielectric regulation framework for lightweight, broadband, and thermally stable electromagnetic absorbers.