Tunable electromagnetic wave absorbing properties of carbon nanotubes/carbon fiber composites synthesized directly and rapidly via an innovative induction heating technique

Carbon nanotubes (CNTs) can create a larger specific surface area and space conductive network with its in-situ growth on the carbon fiber (CF) felt, which have the potential to be an excellent electromagnetic (EM) wave absorbing materials. Herein, we reported a fast and effective induction heating method to in-situ grow CNTs on the CF matrix to prepare carbon nanotubes/carbon fiber (CNTs/CF) composites. The CNTs/CF composites prepared by rapid induction heating have light weight and excellent flexibility. Due to the dense space conductive network formed by CNTs, the EM wave absorbing properties of CNTs/CF composite features 1% filling amount, thin absorption thickness, and width absorption bandwidth. The minimum reflection loss (RL) and peak location can be tailored by controlling the dopant ratio of ferrocene, range from −44.46 dB at 14.16 GHz (the effective bandwidth below −10 dB was achieved in a wide range from 10.48 to 17.92 GHz at the thickness of 3 mm) to −40.615 dB at 5.36 GHz (the bandwidth below −10 dB is narrowed from 4.80 to 6.24 GHz at the thickness of 4.7 mm). Due to its extremely light weight, excellent EM wave absorbing property and flexibility, CNTs/CF composites have the potential to be used in the chip-shielding field.