Rational design of core-shell Co@C nanotubes towards lightweight and high-efficiency microwave absorption

Abstract

Rationally engineering on nanostructure of electromagnetic absorbers provides massive potential for eliminating the pollution caused by electromagnetic radiation. In this work, a series of core-shell Co@C nanotubes were produced via facile pyrolysis of cobalt carbonate hydroxide hydrate/dopamine precursor. Thanks to the well introduction of core-shell and nanotube structure, Co@C composite shows more superior microwave absorption than pristine Co nanoparticles. The unique microstructure provides abundant heterostructures and conductive paths to induce interfacial polarization and conductive loss for boosting dielectric loss. Through regulating the graphitization layer of C shell, the dielectric property could be further enhanced. Coupled with the favorable magnetic loss from the embedded Co nanoparticles, the products exhibit an optimal absorption intensity of −48 dB under low filler content of 30%. And effective absorption frequency bandwidth is up to 5.2 GHz at small thickness of 1.8 mm. Such excellent achievements demonstrate that the core-shell Co@C nanotube composites can be applied as a promising candidate for lightweight and thin electromagnetic absorption.