Defect-Enhanced\nElectromagnetic Wave Absorption Property\nof Hierarchical Graphite Capsules@Helical Carbon Nanotube Hybrid Nanocomposites

Abstract

Development of high-performance materials\nfor electromagnetic wave\nabsorption has attracted extensive interest, but it still remains\na huge challenge especially in reducing density and lowering filler\nloading. Herein, a hierarchical all-carbon nanostructure is rationally\ndesigned as follows: the defect-rich hollow graphite capsules (GCs)\ncontrolled by the size/density of ZnO templates are synthesized on\nthe surface of helical carbon nanotubes (HCNTs) to form a hybrid nanocomposite,\ndenoted as GCs@HCNTs. As a result, the GCs@HCNTs demonstrate a strong\nand wide absorption performance with a very low filler loading of\n10 wt %. The minimum reflection loss reaches −51.7 dB at 7.6\nGHz, and the effective bandwidth (below −10 dB) ranges from\n8 to 14 GHz, covering the whole X or Ku bands. The hierarchical nanostructure\nand homoatomic heterogeneous interface are beneficial to impedance\nmatching and bring additional dipole polarization enhanced by the\nstructural defects, which may enlighten the design of ultralight and\nbroadband high-performance electromagnetic wave absorption materials.