Electromagnetic oscillation induced graphene-based aerogel microspheres with dual-chamber achieving high-performance broadband microwave absorption

Abstract

Graphene-based aerogels have indeed generated significant interest in manufacturing microwave absorbers with ultra-low density and high efficiency. Nevertheless, unitary loss mechanism and impedance mismatch hinder corresponding application. Furthermore, it is essential to address the challenges related to structure control strategy and explanation of the loss mechanism. Dual-chamber graphene-based aerogel microspheres (AMs) with heterogeneous interfaces were fabricated through electrospinning-freeze drying and subsequent calcination. Significant differences are observed in reflecting and scattering of shell and dual-chamber structure against electromagnetic wave (EMW), enabling electromagnetic oscillation, sequential absorption and multi-level coupling of EMW. In addition, the dual-chamber construction is a pivotal role in optimizing impedance matching. In this regard, dual-chamber structure graphene-based AMs with 5 wt% loading were synthesized and exhibited excellent loss ability to EMW in the range of 5–18 GHz, which manifest −28.12 dB at 15.62 GHz, and accordingly, the fE is 6.0 GHz at 2.2 mm thickness, achieving full coverage dissipation of Ku-band. The results demonstrate that the dual-chamber graphene-based AMs achieve the effect of multi-frequency compatible and broadband microwave absorption at low thickness. The integration of the ideation of heterogeneous dual-chamber AMs with electromagnetic-oscillation and sequential loss provides a unique and innovative strategy for modulating lightweight and broadband efficiency absorbers.