Sustainable Wood-Derived Ultralight Porous Carbon Aerogel Modified by CoNi Nanoparticles for Infrared Stealth and Multiband Microwave Absorption

With the increasing concern over electromagnetic (EM) pollution and the need for military camouflage, there is growing interest in the search for materials with efficient microwave absorption (MA) and infrared stealth performances. This study reports the synthesis of lightweight compressible metal–organic framework/wood-derived CoNi nanoparticle-deposited carbon aerogel, which involves freeze-drying and pyrolysis processes. The presence of CoNi nanoparticles within the carbon matrix significantly improves the impedance matching, leading to stronger MA. The optimum reflection loss of the wood carbon@CoNi aerogels could reach −70.6 dB, while the bandwidth achieved was 7.44 GHz at a thickness of 2.16 mm. The maximum effective absorption bandwidth could cover the whole Ku band (10.72–18 GHz), X band (7.04–12.48 GHz), and 60% of the C band (5.6–8 GHz) when the thickness was adjusted to 2.11, 2.93, and 3.63 mm, respectively. Moreover, the porous nature of the aerogel facilitates thermal insulation, making it an excellent candidate for infrared stealth. This work presents a sustainable and effective approach to the synthesis of advanced materials for microwave attenuation and infrared stealth, showing great potential in fields of managing EM pollution and thermal camouflage.