Constructing core-shell SiC@C nanofiber network structure to enhance conductive loss for efficient microwave absorption

Abstract

The impedance mismatch and insufficient conductivity of SiC limit its application as an absorber. Appropriate microstructure design can optimize the impedance matching and conductive loss of the material. Therefore, core-shell SiC@C nanofibers is successfully prepared by coaxial electrospinning process and high-temperature thermal reduction strategy. The hollow core-shell structure was formed by controlling the carbon thermal reduction temperature to achieve the diffusion reaction between carbon and SiO 2 , which synergistically improved the impedance matching of the composite with SiO 2 . In addition, excess Carbon enhanced the conductive properties of the core-shell SiC@C nanofibers. The interconnected nanofiber structure created a comprehensive three-dimensional conductive network. This integrated network significantly enhanced the composite's conductive loss mechanisms, which consequently led to superior electromagnetic wave attenuation capabilities. At the thermal condition of 1450℃, the composite material exhibited exceptional electromagnetic wave absorption capabilities. The material demonstrated a significant minimum reflection loss (RL min ) value of -66.64 dB. Furthermore, when configured with a matching thickness of 2.09 mm, the core-shell SiC@C nanofibers achieved a remarkable maximum effective absorption bandwidth (EAB max ) of 7.52 GHz, covering the frequency range from 9.28 to 16.8 GHz. This work not only provides a way of designing SiC@C nanofibers with core-shell structure, but also provides new insights into impedance regulation and conductive network construction.