Controllable heterogeneous interfaces of cobalt/carbon nanosheets/ rGO composite derived from metal-organic frameworks for high-efficiency microwave attenuation

Abstract

Structural design and composition control are crucial in determining the EM wave attenuation of an absorber; however, the balancing of the EM parameters has always been a formidable challenge. Here, we successfully designed a 3D hierarchical Co/carbon nanosheets (CNS)/rGO magnetic-dielectric composite with controllable composition and microstructure as a high-efficiency absorber by using a three-step route. Benefiting from the synergetic effect and heterogeneous interfaces, the hierarchical Co/CNS/rGO composite displayed strong microwave attenuation and broad absorption frequency band. Furthermore, the nanocomposite with porous structure promoted multiple reflection and scattering, thereby improving the attenuation capacity. The hierarchical Co/CNS/rGO composite exhibited strong microwave absorption capabilities when the filler loading was 20 wt%. Specifically, the maximum reflection loss (RL) was up to −65.5 dB at 12.4 GHz with a matched thickness of 2.5 mm and the corresponding absorption bandwidth was 8 GHz. Such excellent results not only serve as an inspiration for the enhancement of interfacial polarization of an absorber, but they also provide a novel avenue to synthesize high-efficiency microwave absorber with controllable structural design and composition regulation.