Graphene oxide/Ni/carbon nanocoils synergizing dielectric/magnetic/chiral multiple losses for weather-resistant electromagnetic protective application

Abstract

Coupling carbon-based materials with magnetic nanoparticles is one of effective methods to enhance their electromagnetic wave absorption (EWA) performance. However, magnetic nanoparticles with highly chemically active surfaces are prone to be oxidized and corroded in air, severely hindering their long-term serviceability. Herein, Ni/carbon nanocoils (Ni/CNCs) were coated with ultrathin graphene oxide (GO) via a simple electrostatic self-assembly method to improve simultaneously their EWA and stability. The GO coating enhances interfacial polarization through the introduce of heterogeneous interfaces and significantly improves the oxidation resistance of Ni nanoparticles by shielding them from air. Furthermore, as a representative chiral material, CNCs provide an additional enhancing mechanism for EWA by inducing cross-polarization loss. The uniform distribution of Ni nanoparticles on CNCs introduces magnetic loss and improves impedance matching. Benefiting from the synergistic effect of dielectric, magnetic, and chiral properties, GO/Ni/CNCs composite exhibits superior EWA performance, with a minimum reflection loss of –56.62 dB at an ultrathin thickness of 1.6 mm. Notably, the oxidation temperature of Ni nanoparticles is increased by approximately 100 °C. To enhance weather resistance, GO/Ni/CNCs are further embedded in a polytetrafluoroethylene (PTFE) matrix. The resulting PTFE/GO/Ni/CNCs film demonstrates excellent photothermal, hydrophobic, and corrosion-resistant properties. Moreover, by adjusting the filling loading of GO/Ni/CNCs, PTFE/GO/Ni/CNCs undergo a controllable transformation from EWA to electromagnetic interference (EMI) shielding. An absorption-dominated shielding film with absorption coefficient of 0.63 was further designed and fabricated based on the asymmetric gradient double-layer structure of two PTFE/GO/Ni/CNCs films. This work provides a valuable inspiration for designing advanced electromagnetic protective materials with enhanced environmental stability.