Meixi Zhang a b, Qingsong Li a, Xinchi Zhang a, Mingsen Zheng a, Zhiyuan Jiang a, Zhimin Ye b, Jinhui Zhang c, Zhaoxiong Xie a

DOI: 10.1016/j.carbon.2025.120949

https://doi.org/10.1016/j.carbon.2025.120949

Abstract

       The multifunctional coupling effect of multi-scale composite materials opens up a highly promising path for the development of radar/infrared compatible stealth materials. However, scale mismatch and limited in-situ characterization techniques make it difficult to obtain a quantitative explanation for the stealth mechanism of multiscale composite systems, which seriously restricts the development of related materials and the further improvement of their performance. In this study, polyimide/carbon black/graphene sheets (PI/CB/GSs) composite foams are successfully prepared, and the stealth enhancement mechanisms of structures and components at different scales are decoupled and revealed by experiments and simulations. The linear, nanoscale distribution of CB nanoparticles within the matrix reduces the heat accumulation from infrared absorption, thereby facilitating infrared stealth. The presence of large-diameter GSs achieves effective thermal management by delaying temperature rise and evenly distributing heat. Electric field reconstruction formed by microwave-induced electronic anisotropy drives excellent microwave attenuation. As a result, the PI/CB/GSs-III foam exhibits a low infrared emissivity of 0.39 in the 8–14 μm wavelength band and a broad effective absorption bandwidth of 15 GHz with a minimum reflection loss of −48.74 dB. This work breaks through the previous qualitative understanding of the stealth mechanism of carbon materials in composite systems and reveals their stealth enhancement mechanism in a semi-quantitative manner, providing key support for quantitative research in this field.

Graphical abstract