Multilevel Structural Design and Heterointerface Engineering of a Host–Guest Binary Aerogel toward Multifunctional Broadband Microwave Absorption

Abstract

The design of aerogels featuring high-performance electromagnetic wave absorption, multifunctionality, and high mechanical strength is of great interest for applications in complex and extreme environments. To satisfy the above requirements, novel multifunctional microwave absorption aerogels based on a multilevel structural design and host–guest heterointerface engineering strategy are reported herein, in which a freeze–thaw-assembled reduced graphene oxide (rGO) aerogel as a host is confined in an in-situ-generated guest, bridged polysilsesquioxane (BPSi) aerogel. The resulting host–guest rGO-BPSi aerogel achieves a minimal reflection loss of −51.2 dB with a broad effective absorption bandwidth of 8.4 GHz at a low filling ratio (6.2 wt %), which is attributed to the enhanced impedance matching of the gradient composition, various dielectric losses, and multiple scattering occurring within hierarchically porous structures. Furthermore, the excellent structural robustness and machinability, as well as the superhydrophobicity, thermal insulation, and antifreezing performance, guarantee the stable and durable microwave absorption application of the aerogel and resistance against deformation, water, humidity, and cold and hot environments. This design integrates multiple functionalities into a host–guest aerogel-in-aerogel system, providing valuable insights for the creation of advanced functional aerogels for diverse applications.

Microstructural evolution and electromagnetic wave absorbing performance of single-source-precursor-synthesized SiCuCN-based ceramic nanocomposites

“…Therefore, it is critical to put forward perspectives on excellent electromagnetic wave (EMW) absorbing materials which can be used at high temperatures [4][5][6][7][8]. Polymerbased composites have visible advantages such as low density and excellent absorption response, but they cannot be used at high temperatures due to limited thermal stability and degraded mechanical properties [9].…”

“…Nevertheless, their magnetic characteristics disappear immediately at temperatures higher than their Curie points [7,10]. Therefore, ceramic-based EMW absorbing materials which can attenuate EMW energy via electrical conduction loss or dielectric loss mechanisms J u s t A c c e p t e d attract much attention in recent years due to their potential to be used at high temperatures [4][5][6][7][8].…”

Bridged polysilsesquioxane‐derived SiOCN ceramic aerogels for microwave absorption

“…[1][2][3] Currently, a variety kinds of microwave absorption materials have been developed. Carbon-based materials, such as graphene-based materials [4][5][6] and biomass-derived carbon, 7,8 are widely used in microwave absorption due to their low density, tunable electrical conductivity, and excellent dielectric loss capability, while limited by their poor anti-oxidance properties at high temperatures. Magnetic materials, including magnetic metals and ferrites, process high electromag-netic wave absorption efficiency attributed to the magnetic loss as well as compatible dielectric loss.…”

Carbonized Kevlar Nanofiber/Carbon Nanotube/Magnetic Nanoparticle Hybrid Aerogel Fibers for Microwave Absorption

“…The KCF-750 has the characteristics of large porosity and low density, which means that 3D conductive networks can be efficiently formed under low content of conductive nanomaterials. 3D networks can enhance conductivity loss and eddy current loss, inducing current and rapidly converted it into Joule heat . Meanwhile, the aerogel framework also inhibits the uneven dispersion and agglomeration of the nanomaterials in the matrix phase.…”

“…3D networks can enhance conductivity loss and eddy current loss, inducing current and rapidly converted it into Joule heat. 12 Meanwhile, the aerogel framework also inhibits the uneven dispersion and agglomeration of the nanomaterials in the matrix phase. Furthermore, a large specific surface area and pore volume can promote microwave absorption, due to the enhanced interfacial polarization and the abundant sites for microwave absorption, transmission, and scattering.…”