Pressure-Mediated In Situ Fabrication of Soybean/Rice-Shaped High-Entropy Alloy/MWCNTs Aerogels Toward Ultralight Multispectral Stealth With Integrated Microwave Absorption, Thermal Insulation and Flame Retardancy

Synergistic radar-infrared dual-band camouflage is severely restricted by an inherent contradiction between microwave-derived heat release and thermal insulation, while conventional monolithic high-entropy alloys suffer from high density and poor impedance matching for integrated stealth applications. Herein, soybean-shaped and high-aspect-ratio rice-shaped FeCoNiCuMn high-entropy alloys are in situ anchored onto multi-walled carbon nanotube networks via pressure-regulated hydrothermal synthesis, yielding ultralight aerogels with an ultra-low density of 0.014 g·cm −3 . Optimized rice-structured aerogel delivers a broad effective absorption bandwidth of 5.13 GHz at merely 2.00 mm thickness, a minimum reflection loss of −70.01 dB, and an exceptional specific reflection loss of 419.2, surpassing most reported analogs. CST simulations verify 11.60 dB·m 2 radar cross-section reduction, guaranteeing outstanding radar stealth for unmanned aerial vehicle coatings. Impressively, the optimized rice-like HEAAs composite synchronously achieves ∼30 dB electromagnetic shielding, favorable infrared camouflage, fire retardancy and thermal insulation. Mechanism analysis confirms the high-aspect-ratio configuration constructs continuous conductive pathways and abundant heterogeneous interfaces to harmonize dielectric dissipation and impedance matching. This morphology-tuning strategy guides the design of next-generation multifunctional absorbers for harsh aerospace environments.