Partially contacted NixSy@N, S-codoped carbon yolk-shelled structures for efficient microwave absorption

Abstract

Reasonable structure design of an absorber is important to its microwave absorption property. Herein we design a “non-standard” yolk-shelled nanostructure with a morphology mediated between core-shelled and yolk-shelled structures using NixSy sphere as yolk and N, S-codoped carbon as shell (n-NixSy@NSC). The n-NixSy@NSC possesses merits of both core-shelled and yolk-shelled nanostructures, resulted in its excellent microwave absorption performance. The optimal n-NixSy@NSC has a minimal reflection loss of −37.2 dB as the matching thickness is only 1.5 mm, superior to that of the bared NiS2 sphere and previously reported absorbers with similar structure and composition. The experimental results and density functional theory calculations indicate that the enhanced microwave absorption performance of the n-NixSy@NSC is attributed to the increased electrical conductivity and interfacial polarization relaxation as well as the improved impedance matching feature. Our results highlight an efficient strategy for design and fabrication of high-performance microwave absorbers.