Biomass‑derived anisotropic silicon carbide aerogels with orientation‑dependent electromagnetic absorption and high‑temperature insulation performance

Researchers have developed an ultralight, anisotropic silicon carbide (SiC) aerogel using cornstalk biomass as a carbon source. Produced through a carbonisation–thermal reduction process, the aerogel has a density of less than 41.8 mg/cm³ and an oriented porous structure that can respond more effectively to environmental conditions. The team published their study in the KeAI journal Defence Technology.

"Conventional biomass-derived carbon aerogel absorbers cannot meet the service requirements of high-temperature aerospace scenarios, which are plagued by severe oxidation failure under hot-oxygen environments," explains corresponding author Professor Bingbing Fan. “To overcome this material bottleneck, we selected natural corn-stalk pith with intrinsic aligned honeycomb channels as biotemplate and explored anisotropic SiC aerogel prepared via carbonization and catalyst-free carbothermal reduction.”

The researchers produced three distinct directional specimens: parallel-growth, 45o-diagonal and perpendicular-growth SiC aerogel, each showing vastly different electromagnetic-wave absorption and thermal insulation performances. “Though all samples possess lightweight porous features, only the perpendicular-growth sample delivers outstanding comprehensive properties,” says Fan. “The parallel-growth counterpart exhibits relatively weak absorption capacity and inferior heat-shielding effect, which cannot satisfy practical protection demands.”

The team then implemented a series of material characterizations including SEM, TEM and vector network analyzer tests to clarify structure‑property correlation, while adopting RCS simulation to assess real-world stealth potential. “Abundant grain boundaries, stacking faults and heterogeneous interfaces inside SiC aerogel serve as charge-accumulation sites and produce strong interfacial polarization,” shares Fan. “The inherited honeycomb pore architecture reshapes heat conduction and electromagnetic‑wave propagation paths for different orientations.”

Experimental results demonstrated that biomass‑induced anisotropy dominates the multifunctional performance of SiC aerogel. "This study uncovers the structure‑function coupling mechanism of biomass-originated anisotropic SiC aerogel," adds Fan. "It provides a feasible green preparation strategy for developing integrated materials combining electromagnetic absorption and high-temperature thermal insulation."

Contact author details:

Bingbing Fan, School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, 450001, China. fanbingbing@zzu.edu.cn

Funder:

This work was supported by Natural Science Foundation Outstanding Youth Fund Project of Henan Province (Grant No. 242300421009), the Joint Fund of Research and Development Program of Henan Province (Grant No. 222301420002), the National Natural Science Foundation of China (Grant Nos. U21A2064, 52502079), Natural Science Foundation of Henan Province (Grant No. 242300421056), China Postdoctoral Science Foundation (Grant No. 2024M760816), Henan Province Science and Technology Research Project (Grant No. 252102231066), the Youth Research Funds Plan of Zhengzhou University of Aeronautics (Grant No. 25ZHQN01020), Royal Society Wolfson Visiting Fellowship (Grant No. RSWVF\25\R1\1008).

Conflict of interest:

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

See the article:

Yayu Zhao, Limeng Song, Linan Wang, Xiaoqin Guo, Hailong Wang, Rui Zhang, Peng Liang, Xiaohan Wang, Ye Yuan, Yanqiu Zhu, Bingbing Fan, Biomass‑derived anisotropic silicon carbide aerogels with orientation‑dependent electromagnetic absorption and high‑temperature insulation performance, Defence Technology, Volume 61, July 2026, Pages 1-14, https://doi.org/10.1016/j.dt.2025.10.014