Experimental and theoretical study on broadband electromagnetic wave absorption of algae-like NiO/carbon nanotubes absorbers

Abstract

Rational construction of nanocomposites with special structure is still a considerable challenge in developing high-performance electromagnetic (EM) wave materials. In this work, NiO and multiwall carbon nanotubes(MWCNTs) intertwined as a new algae-like material is designed and fabricated by a facile and simple strategy to acquire high EM wave performances for the first time. Benefitting from the special nanostructures, which cause rich dipole polarization, interfacial polarization, multiple scattering centers, reduced specific gravity, three dimensional conductive networks, and proper impedance matching, the NiO/MWCNTs nanocomposites with S-6.5 wt% MWCNTs content display superior microwaves absorption capability. With 30 wt% filler loading, it possesses a strong absorption of − 58.27 dB and a wide absorbing bandwidth of 5.25 GHz at a thickness of only 1.6 mm. Additionally, the broad absorption bandwidth of 16.2 GHz can be obtained in the thickness range of 1.5–5.0 mm. To deeply expose the inner EM wave absorption mechanism, the electronic properties of the hetero-interface (NiO and CNTs) are calculated by density functional theory (DFT). The electronic properties reveal the influence of the polarization on the absorption properties at the atomic level. The combination of experimental and theoretical research clarified the EM wave absorption mechanism of NiO/MWCNTs composites, indicating that NiO/MWCNTs composites can be a high-efficiency absorber with lightweight, ultrathin thickness, broad bandwidth, antioxidation, and strong absorption.