Synthesis of graphene/thorns-like polyaniline/α-Fe2O3@SiO2 nanocomposites for lightweight and highly efficient electromagnetic wave absorber.

α-Fe2O3@SiO2 nanoparticles have been successfully enveloped in graphene nanosheets/thorns-like polyaniline matrix (RGO/thorns-like PANI/α-Fe2O3@SiO2 nanocomposites) by some facile strategies. The measured electromagnetic parameters indicate that the interfacial polarization, the charge transfer, the multiple reflections and scatterings, the Debye dipolar relaxation processes, the magnetic loss, the quarter-wavelength matching and the well-matched characteristic impedance all play significant roles in improving the electromagnetic wave absorption performance. The maximum reflection loss of RGO/thorns-like PANI/α-Fe2O3@SiO2 nanocomposites reaches -50.06 dB at 14.4 GHz with a matching thickness of only 2.3 mm, and the absorption bandwidth with reflection loss less than -10 dB is in the 4.0-18.0 GHz range for the absorber thickness of 1.5-5.5 mm. Moreover, the adding quantity of nanocomposites in the paraffin matrix is only 16.7 wt%. Consequently, it is believed that the nanocomposites could be used as an excellent electromagnetic wave absorber with lightweight, thin thickness, broad bandwidth and strong absorption.