High electromagnetic wave absorbing performance of activated hollow carbon fibers decorated with CNTs and Ni nanoparticles

Activated hollow carbon fibers (ACHFs) decorated with carbon nanotubes (CNTs) and nickel nanoparticles (CNTs-Ni-ACHFs) were prepared by thermal reduction and chemical vapor deposition technique. Microwave reflection loss, permittivity and permeability of CNTs-Ni-ACHFs composites as novel electromagnetic wave absorbents were studied in the frequency range of 2-18 GHz. It was demonstrated that CNTs-Ni-ACHFs absorbents possessed the best microwave absorbing performances whose minimum reflection loss was −43.457 dB at 13.10 GHz with a thickness of 2.0 mm, which is much better than those of Ni-ACHFs and ACHFs samples. The dielectric polarizations and magnetic loss derived from the effect of the porous structures, Ni nanoparticles, and defects in the CNTs-Ni-ACHFs composites are playing an important role for the excellent microwave absorbing performances.