Preparation and electromagnetic wave absorption properties of CoNi@SiO₂ microspheres decorated graphene–polyaniline nanosheets

In this work, we successfully parepared the quaternary composites of CoNi@SiO₂@graphene@PANI via a four-step method. The structures, chemical composition and morphologies of obtained composites are analyzed in detail. The electron microscopy results show spherical CoNi@SiO₂ particles evenly dispersed into the surface of graphene@polyaniline nanosheets. The electromagnetic parameters indicate that CoNi@SiO₂@graphene@PANI exhibits enhanced electromagnetic absorption properties compared to CoNi@SiO₂, which can be mainly attributed to the improved impedance matching and multi-interfacial polarization. The maximum reflection loss of CoNi@SiO₂@graphene@PANI can reach − 43 dB at 15.4 GHz and the absorption bandwidth with the reflection loss exceeding − 10 dB is 5.7 GHz (from 12.3 to 18 GHz) with the thickness of 2 mm. Our results demonstrate the quaternary composites composed of CoNi@SiO₂ microparticles and rGO–PANI nanocomposites can serve as light weight and high-performance EM absorbing material.