Ni@Carbon nanocomposites with hierarchical three-dimensional network for electromagnetic waves absorption

The design of a novel magnetic carbon nanocomposite with unique structure and element doping plays an important role in the development of electromagnetic microwave absorption (EMA) materials and the improvement of its performance. In this work, the EMA properties and mechanism of N-doped Ni@carbon network (Ni@CN) nanocomposite via polydopamine-assisted pyrolysis were systematically investigated. The networked microstructure can increase the multiple scattering of electromagnetic microwaves and thus reduce the intensity of incident microwave. The surface electronic structure of carbon is effectively regulated by Ni particles, which improve the impedance matching and increase ability of eddy current loss. The doping of N atoms provides dipole polarization. These causes the Ni@CN to display remarkable EMA performance, in which the maximal absorption reaches-45 dB and the maximum effective absorption bandwidth is from 10.9 to 16 GHz (5.1 GHz). This research indicates that strategy of Ni composite carbon network provides a new way for the rational design of lightweight carbon-based EMA material.