Abstract: Multicomponent composites are considered conducive to electromagnetic wave (EMW) absorption, as multiple loss synergistic effect from each component, enhance the attenuation ability of EMW and optimize impedance matching. In this study, carbon material was modified by both semi-conductive and magnetic matters to improve their absorbing performance. The carbon-based fibrous composites of CeO₂ and Co were prepared by electrospinning and subsequent carbonization. At a filling rate of 35 wt.%, the CeCoC nanocomposite fibers exhibit a minimum RL value of -61.4 dB at 2.2 mm, and an effective absorption bandwidth (EAB) of up to 7.6 GHz. The excellent absorbing performance is derived from the improved dielectric loss and optimized impedance matching. The introduction of rare earth oxide CeO₂ not only helps to maintain the fibrous structure, but also promotes conduction loss. Especially, oxygen vacancy defects introduced by CeO₂ greatly improved the dielectric loss capacity. The introduction of Co particles optimizes the impedance matching to reduce the matching thickness and strengthen magnetic loss. This study demonstrates the potential of rare earth oxides in improving EMW absorption performance, and opens up new opportunities for the development of advanced materials for high-performance EMW absorption applications.

Key words: Electrospinning, Nanocomposite fiber, Electromagnetic wave absorption, Cerium dioxide, Metallic cobalt