Recently, a research team led by Prof. HUANG Zhulin from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, successfully synthesized a flexible nanofiber felt with ultralow thermal conductivity and exceptional electromagnetic wave absorption properties.
The findings were published in the Journal of Materiomics.
With the rapid advancement of modern technologies, there is growing demand for materials that can efficiently absorb electromagnetic waves while also being lightweight, heat-resistant, and durable under extreme conditions. However, current carbon-based materials, though widely used, often suffer from poor impedance matching and limited performance in harsh environments.
To overcome these challenges, the researchers designed a novel ZrO₂/ZrB₂/C (zirconia/zirconium diboride/carbon) nanofiber felt. By incorporating ZrO₂ and ZrB₂ into carbon fibers, they successfully addressed the issue of excessive electromagnetic wave reflection caused by the high conductivity of pure carbon. This multi-component composite structure greatly improved impedance matching and enhanced the material' s ability to absorb electromagnetic waves across a broad frequency range.
The new material achieved a maximum reflection loss of -54 dB and a broad absorption bandwidth of 3.1 GHz, indicating excellent microwave absorption capabilities. In addition, theoretical calculations revealed that the ZrO₂/ZrB₂ components promote electron transfer at the interfaces, boosting interfacial polarization—key mechanisms for efficient electromagnetic wave attenuation.
Further simulations also demonstrated the material' s radar stealth capability, showing its ability to reduce radar wave scattering—an essential feature for stealth applications.
Beyond its electromagnetic performance, the material also showed exceptional thermal insulation properties. Its complex multi-interface structure acts as a barrier to heat flow while its surface properties enhance heat radiation dissipation. As a result, the material achieved an ultralow thermal conductivity of just 0.016 W·m⁻¹·K⁻¹ at 1100 °C, which is among the lowest reported for such materials.
This study paving a novel pathway for designing multifunctional microwave-absorbing materials suitable for complex and extreme environments, according to the team.
Reflection loss diagrams for four sample groups with varying ZrO₂/ZrB₂ loading contents, and correlations between simulated thickness and peak frequency for the four sample groups. (Image by Yang Chengwan)
