Ultralight multifunctional aerogels with in situ enhanced chitosan networks at micro-/macroscale for super-efficiency...

Concurrently achieving lightweight, multifunctionality, excellent environmental adaptability, and broadband microwave absorption represents the inevitable trend in the development of microwave absorbing materials. Herein, an ultralight, elastic, multifunctional chitosan-based aerogel enhanced by carbon nanotubes (CNTs) and carbon fibers (CF) at micro-/macroscale is reported, and its super-efficiency microwave absorption is realized by the electromagnetic metastructure absorbers (EMAs) design. The resulting CF-C/C aerogel demonstrates ultra-low shrinkage (6.3 %), low density (19.64 ± 1.06 mg/cm³), low thermal conductivity (27.43 ± 0.68 mW·m^-1·K^-1), as well as exhibits self-extinguishing properties, robust fatigue mechanical performance and good dielectric properties. In response to the challenge of low-frequency microwave absorption, laser etching technology was used to shape the CF-C/C aerogel into periodic metastructures, achieving ultra-wideband (37.9 GHz within S - Ka bands), wide-temperature range (-20-200 °C), and wide-angle (5-70° incidence angle) microwave absorption characteristics. These exceptional properties highlight the practical potential of aerogel metastructure absorbers in complex electromagnetic environment.