Enhanced microwave absorption performance originated from interface and unrivaled impedance matching of SiO2/carbon fiber

Carbon fiber (CF) is a research focus due to its high performance in aviation, aerospace, and defense. However, its inherent high electrical conductivity makes it impedance mismatched. Herein, a material was prepared by grafting and coating SiO2 on short-cut carbon fiber (SCCF). The structure of SiO2 layer coated on the surface of SCCF brings about a stronger synergy of multiple loss mechanisms such as interface polarization and dipole polarization. It is shown that with the increase of SiO2 content, it has a significant optimizing effect on the impedance matching of SiO2/SCCF composites, and the SiO2 layer structure increases the loss mechanisms of interface and dipole polarization. At 2 vol% filling ratio and 6.35 GHz frequency, corresponding reflection loss (RL) value was -29.3 dB. Meanwhile, the SiO2/SCCF composite achieves an ultra-broadband electromagnetic wave absorption performance with an effective absorption bandwidth (EAB) of 12.3 GH. Therefore, this work provides a strategy for designing efficient and lightweight CF-based composites with electromagnetic wave absorption performance.