A novel donuts-like CoO hollow nanostructure intertwined with MWCNTs as a high-efficiency electromagnetic wave absorber

Abstract

Rational construction of nanocomposites with special hollow structure is still a considerable challenge in developing high-performance electromagnetic wave absorption materials. In this work, a novel donuts-like CoO hollow nanostructure intertwined with multiwall carbon nanotubes (MWCNTs) was designed and fabricated by a facile and simple strategy to acquire the excellent EM wave performances for the first time. Benefitting from the special nanostructures of donuts-like CoO intertwined with MWCNTs, which cause rich interfacial polarization, multiple scattering centers, reduced specific gravity, three dimensional conductive networks, and proper impedance matching, the CoO/MWCNTs nanocomposites with proper carbon content display superior microwaves absorption performance. With a filler loading of 25 wt%, CoO/MWCNTs nanocomposites with 7 wt% MWCNTs has a strong absorption of −72.57 dB at a 2.0 mm thickness, and its effective absorption bandwidth (EAB) reaches 4.18 GHz. Even with an ultrathin thickness of 1.5 mm, it possesses strong absorption of −42.1 dB with an EAB of 3.3 GHz. Additionally, the EAB of 14.5 GHz with respect to 1.5–5.0 mm thickness range can be obtained. In light of the above advantages, the CoO/MWCNTs nanocomposites can be an effective absorber with lightweight, ultrathin thickness, broad bandwidth, antioxidation, and strong absorption.