The preparation of carbonized silk cocoon-Co-graphene composite and its enhanced electromagnetic interference shielding performance

In this work, 3D hierarchical carbonized silk cocoon-Co-graphene composite possesses combined advantages of lightweight, porous, nitrogen-doped and environmentally friendly is prepared with silk cocoon as the precursor of biomass carbon, Co nanoparticles as a sandwich layer and graphene as outer layer via a facile soaking and carbonization method. The carbonized natural silk cocoon possesses the electromagnetic interference shielding effectiveness of 27 dB in 12.4-18 GHz (Ku band), and it is enhanced to 55 dB in 18 GHz with the presence of graphene and Co nanoparticles. The carbonized silk cocoon and the synthesized carbonized silk cocoon-Co-graphene (15.79 wt% of Co nanoparticles) not only show the superior electromagnetic interference shielding effectiveness, but has the outstanding specific shielding effectiveness of 2322 dB cm(3)/g and 664 dB cm(3)/g, respectively, both higher than the value of previous other shielding materials. Therefore, it exhibits great potential for the application in electromagnetic interference shielding materials.