Facile synthesis of Ni/PANI/RGO composites and their excellent electromagnetic wave absorption properties

• A ternary composite of Ni/polyaniline (PANI)/reduced graphene oxide (RGO) was synthesized via a two-step method.
• The morphology, microstructure, magnetic and electromagnetic properties were characterized.
• The maximum reflection loss of the ternary composites can reach −51.3 dB at 4.9 GHz with the thickness of 3.5 mm.
• The absorption bandwidth exceeding −10 dB is 3.1 GHz with the thickness of 3.5 mm.

A ternary composite of Ni/polyaniline (PANI)/reduced graphene oxide (RGO) was synthesized via a two-step method, a facile hydrothermal route (Ni/RGO) in first step and followed by the in situ polymerization of PANI on the surface of Ni/RGO. The morphology and microstructure of as-prepared Ni/PANI/RGO composite were characterized by XRD, TEM and XPS. The results show that Ni nanoparticles with a diameter around 20–30 nm are grown on the RGO sheets and the coating layer of PANI covers over the surface of Ni/RGO composite. The as-prepared Ni/PANI/RGO composite shows enhanced electromagnetic absorption properties compared with Ni/RGO, which is mainly due to the synergistic effect of dielectric loss and magnetic loss and the enhanced interfacial effects. The maximum reflection loss of the ternary composite can reach −51.3 dB at 4.9 GHz and the absorption bandwidth with the reflection loss less than −10 dB is 3.1 GHz (from 3.3 to 6.4 GHz) with the thickness of 3.5 mm. When the thickness varies from 3 to 5 mm, all the maximum reflection losses are less than −20 dB. It is believed that such composite can serve as an attractive candidate for the new type of high performance microwave absorbing material.