Development of high-performance materials for electromagnetic wave absorption has attracted extensive interest, but it still remains a huge challenge especially in reducing density and lowering filler loading. Herein, a hierarchical all-carbon nanostructure is rationally designed as follows: the defect-rich hollow graphite capsules (GCs) controlled by the size/density of ZnO templates are synthesized on the surface of helical carbon nanotubes (HCNTs) to form a hybrid nanocomposite, denoted as GCs@HCNTs. As a result, the GCs@HCNTs demonstrate a strong and wide absorption performance with a very low filler loading of 10 wt %. The minimum reflection loss reaches -51.7 dB at 7.6 GHz, and the effective bandwidth (below -10 dB) ranges from 8 to 14 GHz, covering the whole X or Ku bands. The hierarchical nanostructure and homoatomic heterogeneous interface are beneficial to impedance matching and bring additional dipole polarization enhanced by the structural defects, which may enlighten the design of ultralight and broadband high-performance electromagnetic wave absorption materials.
Keywords: EM wave absorption; defects; graphite capsules; helical carbon nanotubes; homoatomic heterogeneous interface.