Superior Microwave Absorption Properties Derived from the Unique 3D Porous Heterogeneous Structure of a CoS@Fe3O4@rGO Aerogel

A novel CoS@Fe3O4@rGO aerogel with a unique 3D porous heterostructure was prepared via the solvothermal method, in which cobalt sulfide (CoS) microspheres embedded with Fe3O4 nanoparticles were randomly scattered on reduced graphene oxide (rGO) flakes. The introduction of magnetic Fe3O4 nanoparticles and rGO regulated the impedance matching, and the excellent electromagnetic wave (EMW) absorption capability of the CoS@Fe3O4@rGO aerogel could be attributed to optimal dielectric loss and abundant conductive networks. The results demonstrated that the minimum reflection loss (RL) value of CoS@Fe3O4@rGO aerogel was −60.65 dB at a 2.5 mm coating thickness with an ultra-wide bandwidth of 6.36 GHz (10.24–16.6 GHz), as the filler loading was only 6 wt%. Such a lightweight CoS@Fe3O4@rGO aerogel with an outstanding absorbing intensity and an ultra-wide effective absorption bandwidth could become a potential EMW absorber.