Synthesis of ultralight hollow SiC/C nanofiber for highly efficient electromagnetic wave absorption

The rapid advancement of military equipment and civilian facilities demands electromagnetic wave protection materials that can withstand harsh service conditions such as high temperatures, oxygen-rich environments, and high humidity. Developing multifunctional electromagnetic wave absorbing materials adapted to complex environments is therefore an urgent priority. Carbon materials are widely used in electromagnetic protection due to their lightweight nature, high melting point, and strong loss capability; however, they are prone to oxidation and performance degradation at high temperatures. Introducing dielectric ceramic materials with high thermal stability and oxidation resistance into carbon matrices has thus become an effective strategy to overcome the high-temperature failure of carbon-based absorbers. Silicon carbide (SiC), a wide-bandgap semiconductor, offers excellent mechanical properties, corrosion resistance, and high-temperature stability. Through silicon vapor deposition, SiC can be in situ generated on carbon substrates, which not only consumes part of the graphitic carbon to optimize impedance matching but also enhances the oxidation resistance and thermal stability of the matrix, while creating heterogeneous interfaces to strengthen polarization loss. However, the density of SiC is significantly higher than that of pyrolytic carbon, and its sole incorporation would undermine the lightweight advantage of carbon-based materials. Constructing hollow SiC/C nanofiber aerogels is therefore a promising approach to achieve a synergistic combination of lightweight design, high stability, and efficient wave absorption, offering a comprehensive solution to high-temperature electromagnetic protection challenges.

Recently, a team of materials scientists led by Wang Guang-Sheng from Beihang University reported for the first time the synthesis, microstructure, elastic properties, fatigue resistance, and electromagnetic wave absorption performance of hollow SiC/C nanofiber aerogels. This work not only elucidates the mechanism behind the excellent wave-absorbing properties of hollow SiC/C nanofibers but also highlights their significant potential for applications in high-temperature electromagnetic wave protection.

The team published their work in Journal of Advanced Ceramics on December 16, 2025.

“In this report, we prepared a hollow SiC/C nanofiber aerogel using a hydrothermal-carbothermal reduction method. Initially, coaxial nanocable-structured AgNW@PVA was synthesized via a hydrothermal process. Subsequently, AgNW@PVA aerogel was obtained by freeze-drying. Finally, the AgNW@PVA aerogel was blended with silicon powder and subjected to high-temperature heat treatment, yielding the hollow SiC/C nanofiber aerogel (H-SiC/C NFs). The morphology and SiC content of the hollow nanofibers were effectively regulated by controlling the heat treatment temperature and the C/Si ratio of the reactants.” said Guang-Sheng Wang, professor at School of Chemistry at Beihang University (China), a senior expert whose research interests focus on the controllable preparation and property regulation of electromagnetic functional materials and nanocomposites.

Utilizing ABF-STEM technology, it is revealed that the shell of the H-SiC/C NFs are composed of silicon carbide grains and pyrolytic carbon. HRTEM clearly displays the lattice fringes of the (111) plane of silicon carbide, with an interplanar spacing of 0.25 nm. The abundant heterogeneous interfaces within the hollow SiC/C nanofibers provide the structural foundation for the polarization loss of the material.

“The remarkable elasticity and fatigue resistance of the H-SiC/C NFs aerogel were confirmed through cyclic compression tests. The regular and consistent pattern observed over 100 loading-unloading cycles at 30% strain confirms the aerogel's remarkable structural stability and fatigue resistance.” said Guang-Sheng Wang.

The H-SiC/C NFs exhibits a RL_min of -63.5 dB with a EAB of 4.6 GHz at a thickness of 1.4 mm and an EAB of 7.0 GHz with a RL_min of -30.8 dB at a thickness of 2.4 mm. “The abundant SiC/C interfaces within the hollow SiC/C nanofibers facilitate interfacial polarization loss, the continuous fibrous conductive network provides efficient conductive loss, and the unique hollow structure simultaneously optimizes impedance matching. The synergy of these three factors endows the material with excellent electromagnetic wave absorption performance.” said Guang-Sheng Wang.

Thermogravimetric analysis shows that the mass of H-SiC/C NFs remains largely unchanged when heated to 1000°C. High-temperature in-situ electromagnetic parameter measurements further reveal that the complex permittivity of H-SiC/C NFs remains stable even at 600°C. “These results demonstrate that the H-SiC/C NFs possess excellent high-temperature stability and hold broad application prospects in the field of high-temperature electromagnetic wave protection.” said Guang-Sheng Wang.

Other contributors include Yun-Tian Chen, Hualong Peng, Bo Cai, Chen-Ming Liang, Yu Zhang from the School of Chemistry at Beihang University in Beijing, China; Pei-Yan Zhao from Hangzhou International Innovation Institute, Beihang University in Hangzhou; Pengfei Hu from the Research Institute of Aero-Engine at Beihang University in Beijing, China; Wen-Ping Li from the School of Physics at Beihang University in Beijing, China.

This work was supported by the National Natural Science Foundation of China (No. 22575012, 22505056, 52373259), the Research Funding of Hangzhou International Innovation Institute of Beihang University under No. 2024KQ130.

About Author

Guang-Sheng Wang is a Professor, Ph.D. Supervisor, and Vice Dean of the School of Chemistry at Beihang University. He leads a research team dedicated to the controllable preparation and property modulation of electromagnetic functional materials and nanocomposites.

His work has resulted in over 150 SCI publications in prestigious international journals such as Nature Communications, Advanced Materials, and Angewandte Chemie International Edition, including 18 ESI Highly Cited Papers and 3 Hot Papers. He has an H-index of 57 with more than 11,000 citations.

Wang has been consistently listed among the “World’s Top 2% Scientists” and serves in several academic roles, including Youth Editorial Board Member for Nano-Micro Letters, Committee Member of the Dielectric Polymer Composites and Applications Professional Committee of the Chinese Society for Composite Materials, Committee Member of the Electromagnetic Composite Materials and Applications Professional Committee, and Guest Editor for the International Journal of Minerals, Metallurgy and Materials.

About Journal of Advanced Ceramics

Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen. JAC’s 2024 IF is 16.6, ranking in Top 1 (1/33, Q1) among all journals in “Materials Science, Ceramics” category, and its 2024 CiteScore is 25.9 (5/130) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508