writer：Jiqi Wang, Qiang Li, Jianquan Ren, Aibo Zhang, Qiuyu Zhang, Baoliang Zhang
keywords：Bowknot-like, Convex surface, Acicular structural units, Co@C magnetic nanoparticles, Microwave absorption
source：期刊
specific source：Carbon
Issue time：2021年

Nanoparticles with high roughness and complex surface have strong reflection and scattering ability for electromagnetic wave, which can extend the propagation path of electromagnetic wave in absorbing coating, thus exhibiting better microwave absorbing performance. Constructing complex surface has been considered as an effective way to improve the microwave loss ability of microwave absorbers. In this paper, a novel bowknot-like N-doped Co@C magnetic nanoparticle constituted by acicular structural units (BNCoC) has been designed and prepared. Its precursor (BNCoCP) is synthesized by solvothermal method and converted into BNCoC by subsequent vacuum calcination. The main structure of BNCoC is Ndoped carbon with Co nanoparticles embedded in it. BNCoC contains dielectric and magnetic components that has both dielectric loss and magnetic loss capabilities. Under the synergistic effect of its unique structure, BNCoC exhibits excellent absorbing performance with a minimum reflection loss of
47.6 dB@11.0 GHz@2.7 mm. Furthermore, the effects of calcination temperature and filler content on microwave absorbing performance are investigated. The electromagnetic parameters are analyzed in depth to reveal the microwave loss mechanism. This work reports a novel high-efficiency microwave absorber with unique structure. It provides a new method for microstructure design of microwave absorbing materials.