▎ 摘　　要

In situ polymerization between aniline and ammonium persulfate (APS) under acidic conditions is described for the preparation of graphene-based polyaniline hybrids with investigation of their electromagnetic properties. Samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), transition electron microscopy (TEM) and vector network analysis. The results revealed that the graphene-based PANI hybrids formed a uniform PANI particle coating on the graphene sheets. Such special structures lead to pi-pi interactions between graphene and PANI, and thus the electromagnetic absorption properties are significantly improved versus pure conducting polymers. The maximum reflection loss reaches -32.1 dB at 5.45 GHz with a thickness of 4 mm. The bandwidth (RL < -10 dB) reaches an amazing 5.62 GHz with a thickness of 2 mm. In particular, first-principles calculations based on density function theory (DFT) were carried out to uncover the relationship between dielectric properties and electronic structures.