Hollow Porous Bowl-like Nitrogen-Doped Cobalt/Carbon Nanocomposites with Enhanced Electromagnetic Wave Absorption

A unique hollow porous bowl-like nitrogen-doped cobalt/carbon nanocomposite (HBN-Co/C) composed of Co nano-particles anchored in N-doped porous carbon was designed for enhancing electromagnetic microwave absorption (EMA). The inner cavities of the HBN-Co/C could be regulated to match the impedance and permittivity between the absorber and air, leading to a precise adjustment of the EMA performance. More importantly, the existence of inner cavities decreases the extra multi-interface promoted interfacial polarization and overall density. The synergetic effects of the multicomponents, multiple reflections, and scatterings promoted strong interfacial polarization and facilitated impedance matching. As a result, the HBN-Co/C nanocomposites displayed excellent EMA performance, for which the minimum reflection loss was -42.3 dB at 13.3 GHz with a thickness of only 1.9 mm. The effective absorption bandwidth below -10 dB was up to 5.1 GHz (12.9-18.0 GHz) when the thickness was 1.7 mm. This work provides a facile design and synthesis strategy of novel lightweight electromagnetic wave absorbers with broadband and strong absorption.

Automated summary

A unique hollow porous bowl-like nitrogen-doped cobalt/carbon nanocomposite (HBN-Co/C) with Co nano-particles anchored in N-doped porous carbon was designed to enhance electromagnetic microwave absorption (EMA). The internal cavities of the material could be adjusted to match the impedance and permittivity between the absorber and air, resulting in precise adjustment of EMA performance through synergistic effects of multiple components, reflections, and scatterings. This design strategy led to excellent EMA performance with strong absorption and broad bandwidth.