Enhanced properties of CoS2/Cu2S embedded N/S co-doped mesh-like carbonaceous composites for electromagnetic wave absorption

CoS2/Cu2S embedded N/S co-doped mesh-like carbonaceous composites with enhanced electromagnetic wave absorbing performance was successfully prepared using carboxymethyl cellulose hydrogel spheres as starting materials by freeze-drying and high-temperature carbonization, in which thiourea as a source of N/S was favorably achieved. This newly designed three-dimensional mesh-like structures embedded with CoS2 and Cu2S nanoparticles was confirmed by various techniques, while the N/S co-doped carbonaceous matrix, would contribute to the enhancement of electron transport, interfacial polarization, dipole polarization, ferromagnetic resonance, and magnetic coupling. This unique three-dimensional mesh structure facilitates multiple reflections and scattering of electromagnetic waves within the single matrix. By adjusting the dosage ratio between components and the filling amount of filler, the composite material exhibited a good impedance matching, which promotes the synergy between conductive loss, dielectric loss, and magnetic loss, and improves the electromagnetic wave loss. When the composite is filled with 25 wt%, there is a minimum reflection loss value of −51.68 dB at 5.20 GHz, and when the coating thickness is 4.5 mm, the effective absorption bandwidth is 3.84 GHz when the coating thickness reaches 2.0 mm. The experimental results illustrated that the synthesized composites might be alternative materials for low-frequency band electromagnetic wave absorption.