Shell engineering afforded dielectric polarization prevails and impedance amelioration toward electromagnetic wave absorption enhancement in nested‐network carbon architecture

Abstract

3D reduced graphene oxide (rGO) aerogel has exhibited immense potential as electromagnetic (EM) wave absorbing materials (EWAMs) due to its unique structural advantages, but there still remains a challenge to balance the relationship between impedance matching and EM attenuation capability. Herein, a novel shell engineering strategy is proposed to fabricate 3D rGO-based aerogel with nested-network architecture by coating a dense and continuous heterogeneous layer composed of numerous N-doped porous carbon nanocubes (NPCNs). The formation of heterogeneous layer more or less increases the stability of aerogel structure and suppresses the re-stacking of rGO nanosheets. More importantly, NPCNs on the pore walls of rGO aerogel are amorphous, and thus they not only optimize impedance matching of rGO aerogel, but also induce powerful interfacial polarization thanks to the dielectric difference with rGO aerogel. As a result, the final rGO@NPCNs aerogel produces good EM absorption performance, especially for an effective absorption bandwidth (EAB) of 5.1 GHz with a thickness of merely 1.3 mm. The value of EAB can be further extended up to 12.1 GHz by gradient multilayer architecture design. Numerical simulation technique vividly demonstrates that this shell engineering strategy contributes to the penetration of incident EM wave into rGO@NPCNs aerogel as compared with individual rGO aerogels, and facilitates the generation of adequate heterogeneous interfaces to reinforce interfacial polarization loss. Moreover, rGO@NPCNs aerogel also displays good thermal insulation, waterproof functionality, and radar stealth properties, which fully addresses its bright prospects as an excellent candidate for high-performance EWAMs in the future.