Grow defect-rich bamboo-like carbon nanotubes on carbon black for enhanced microwave absorption properties in X band

Abstract

• By in-situ growing bamboo-like CNTs on CB, a developed conductive network was constructed and plentiful CB/CNT interfaces were introduced to improve the electromagnetic wave loss ability. • Defect-rich CNTs with open atomic edges can endow nanocarbons with a better balance between good impedance matching and strong loss capacity, causing an effective microwave absorption. • The minimum reflection loss and effective absorption bandwidth of CB-CNT with the CNTs growth time of 40 min reach to −53.6 dB and 4.1 GHz with the matching thickness of 2.7 mm, respectively. Due to the limited electromagnetic wave (EMW) loss capacity and agglomeration, carbon black (CB) gradually fails to meet the increasingly harsh demanding conditions. Herein, defect-rich bamboo-like carbon nanotubes (CNTs) were grown on CB by the process of chemical vapor deposition. CNTs prepared in situ on CB can assist it to build a developed multilevel conductive network and introduce plentiful CB/CNTs nano-interfaces. What's more, the defects that accompany the growth of CNTs endow CNTs with a moderate conductivity and good impedance matching, thereby causing an effective microwave absorption (MA). Meanwhile, the high-density defects on CNTs can induce dipole polarization to further strengthen the EMW loss ability. The influence of CNTs with different growth time on MA performance has been explored. Profiting from the structural merits, the synthesized CB-CNT with CNTs growth time of 40 min exhibits the optimal absorbing property, which has the minimum reflection loss of -53.6 dB and maximum effective absorption bandwidth of 4.1 GHz with the thickness of 2.7 mm, covering almost the entire X band. The introduction of defect-rich CNTs significantly enhances the EMW loss ability of CB, which provides a rational strategy for the design of high-efficient microwave absorption materials.