A novel multi-dimensional structure of graphene-decorated composite foam for excellent stealth performance in microwave and infrared frequency bands

Abstract

Microstructure design is an effective strategy to realize multifunctional integration as well as broaden practical engineering application fields of microwave absorbing materials. Herein, a novel Co_1.29Ni_1.71O₄/reduced graphene oxide/calcined melamine (Co_1.29Ni_1.71O₄/rGO/CF) composite foam with a unique dual three-dimensional continuous phase (d-3D-CP) structure has been designed and successfully constructed via a convenient foaming and calcination method. Superior microwave absorption is observed in the Co_1.29Ni_1.71O₄/rGO/CF composite foam whose minimum reflection loss (RL) is up to −53.45 dB at a thickness of 3.0 mm and the effective absorption bandwidth (EAB) (RL < −10 dB) can reach 7.45 GHz (10.55–18.0 GHz). And the EAB can be broadened to 12.45 GHz (5.55–18.00 GHz) through adjusting the thickness, realizing broadband microwave stealth performance. Besides, the composite foam also exhibits outstanding infrared stealth properties at human body temperature as well as the surface temperature (∼56 °C) of operating electronic devices. Furthermore, the strong hydrophobic characteristics also provide stable property guarantee for the composite foam when being applied in various environments. The broadband stealth performance of the graphene-decorated composite foam also makes it possible for achieving comprehensive stealth protection at short and long distances, such as preventing operating electronic equipment from being captured by radar/infrared malicious detection.