Multi-scale nickel embedded carbon nanotube/boron nitride nanoribbon aerogel for integrated electromagnetic wave absorption and thermal infrared stealth

The rapid development of fifth-generation (5G) communication technology has stimulated the urgent demand for wideband and multifunctional electromagnetic wave (EMW) absorption materials. Herein, a multi-scale composite aerogel is constructed by integrating boron nitride nanoribbons (BNNRs) and in-situ grown carbon nanotubes (CNTs) catalyzed by nickel (Ni) nanoparticles into three-dimensional framework. The resulting CNT/Ni/BNNR (CNB) aerogel exhibits excellent EMW absorption performance, with a minimum reflection loss of -57.12 dB and an effective absorption bandwidth of 6.93 GHz, covering both the n79 band (4.4–5.0 GHz) for 5G communication and the Ku band. The hierarchical integration of conductive CNT networks and magnetic Ni nanoparticles within the BNNR framework optimizes electron transport pathways and magnetic-dielectric synergy, thereby facilitating multiple loss mechanisms. Subsequent polydimethylsiloxane (PDMS) impregnation obtains the CNB/PDMS composite with excellent EMW absorption performance, ultra-low thermal conductivity (0.032 W m⁻¹ K⁻¹), outstanding thermal infrared stealth, and good flame retardancy, ensuring promising application potential in harsh environment. This work presents a generalizable strategy for constructing microwave absorbers with wideband absorption and multispectral camouflage capabilities, offering strong potential for multifunctional EMW absorption materials in stealth technology.