Broadband and Lightweight Microwave Absorber Constructed by in Situ Growth of Hierarchical CoFe2O4/Reduced Graphene Oxide Porous Nanocomposites

A broadband and lightweight microwave absorber has attracted soaring research interest because of the increasing demand for electronic reliability and defense security. Lightweight ferrites/graphene porous composites with abundant interfaces are potential high-performance absorbers owing to their balanced attenuation ability and impedance matching. Herein, we synthesized hierarchical CoFe2O4/reduced graphene oxide (CFO/rGO) nanocomposites with a porous structure via an in situ solvothermal method. The electromagnetic parameters of CFO/rGO nanocomposites can be well-adjusted by modulating the weight fraction of rGO. The hierarchical porous structure and proper electromagnetic parameters result in the enhancement of impedance matching and attenuation ability. Benefiting from the controllable composition, hierarchical porous structure, and strong synergetic effect between CFO and rGO sheets, as expected, CFO/rGO nanocomposites exhibit superior microwave absorption performance with an ultrabroad bandwidth reaching 5.8 GHz (8.3–14.1 GHz) with a thin thickness of 2.8 mm. Meanwhile, a strong reflection loss of −57.7 dB at the same thickness is achieved. Considering the outstanding microwave absorption performance, the hierarchical CFO/rGO porous nanocomposites can be employed as a high-performance microwave absorber.