Reduced graphene oxide/Fe2O3 hollow microspheres coated sponges for flexible electromagnetic interference shielding composites

Abstract

In this work, the low-density, compressible and porous composites are fabricated by simply coating polyurethane (PU) sponge with reduced graphene oxide (rGO) and hematite (Fe2O3) hollow microspheres for the application of absorption-dominant electromagnetic interference (EMI) shielding composites in X-band (8.2–12.4 GHz). By coating rGO on the skeleton of PU sponge, the composites possess high EMI shielding effectiveness of 37.45 dB. By further incorporating Fe2O3 hollow microspheres as the coating material along with rGO, the absorption of the electromagnetic waves enhances from 72.6% to 94.5% owing to the enhanced dielectric loss and better impedance matching at the air/shield interface. Moreover, the porous structure of the coated sponge facilitates absorption-dominant EMI shielding effectiveness owing to low density, conduction loss, multiple reflections and scattering of EM waves. In addition, the layered structure can further improve the absorption of the electromagnetic waves up to 97.3% by selectively stacking the rGO coated and rGO/Fe2O3 coated sponges, which serve as reflection and absorption layers, respectively.