Graphene-based aerogel microspheres with annual ring-like structures for broadband electromagnetic attenuation

Abstract

Graphene aerogels have attracted extensive attention in electromagnetic protection due to lightweight and efficient microwave absorbing properties, but until now the design of its shape and structure is still a research hotspot. Herein, reduced graphene aerogel microspheres (CSA-RGO AMs) with annual ring structure with regular interlayer spacing are synthesized by wet spinning-chemical reduction-lyophilization. Due to the special chiral helical structure and electromagnetic cross-polarization, the impedance matching and attenuation ability of microspheres to electromagnetic waves are enhanced. The CSA-RGO AMs at a low load of 4 wt% can achieve the minimum reflection loss (RLmin) of − 63 dB with a thickness of 3.6 mm, and the effective absorption bandwidth (EAB) reaches 7.04 GHz. On this basis, we further obtain polyaniline@reduced graphene oxide microspheres (PANi@RGO AMs) with the same chiral helical structure through in-situ doping polymerization of polyaniline. Heterogeneous interfaces bring the interface polarization and enhance the reflection and scattering of electromagnetic waves. And the corresponding RLmin can reach − 48 dB when the thickness is only 2.8 mm, and the EAB remains 6.88 GHz. Therefore, the new strategy for constructing chiral structures proposed in this study provides a new idea for realizing high-performance electromagnetic wave absorption of graphene-based aerogel absorbers.