Synthesis of Co@N-doped carbon with yolk-shell heterostructures for efficient electromagnetic wave absorption

Regulating the composition and microstructure of nanomaterials is a major challenge in the development of highperformance materials for electromagnetic wave (EMW) absorption. This paper introduces a new lightweight EMW-absorbing material Co@N/C with a yolk-shell structure and compositions of ferromagnetic metal and carbon materials. The minimum reflection loss (RLmin) of the as-designed Co@N/C nanospheres with a filler loading of 25 wt% reaches -67.68 dB and the effective absorption bandwidth of a 1.9 mm thickness is 5.3 GHz. The exceptional absorption performance of the EMW absorption is primarily achieved through the synergistic effect between the Co-carbonaceous material and the yolk-shell structure, which optimizes the impedance matching. The polarization loss, conductivity loss, magnetic loss, and multiple scattering mainly contribute to the excellent EMW-absorption ability of the materials. The proposed method for regulating the structure and morphology of Co@N/C can efficiently construct high-performance EMW absorbers.