Facile fabrication of Hildewintera-colademonis-like hexagonal boron nitride/carbon nanotube composite having light weight and enhanced microwave absorption

Abstract Hildewintera-colademononis-like hexagonal boron nitride carbon nanotubes (BN@CNT) composites can be fabricated via two steps: a composite structure predesign in a solvent and a subsequent thermal treatment process at high temperature. The as-obtained hildewintera-colademononis-like BN@CNT composites contain porous h-BN microrods as stems and CNTs as spines. The densities and specific surface area of these BN@CNT composites can be tuned by adjusting the relative amounts of CNTs in the composites, which can reach 0.072 ± 0.0046 g/cm3 and 583.63 m2/g, respectively. These BN@CNT composites based absorbers show excellent microwave absorption (MA) properties which have effective frequency absorption width (≤-10 dB) from 2.8 to 18 GHz when the absorber thicknesses are in the range of 1.0–6.0 mm, and the minimum RL values can reach up to −48.45 dB for BN@CNTs-3 based absorber with an absorber thickness only of 1.4 mm. Moreover, the widest absorption bandwidth of 4.24 GHz (12.96–17.20 GHz) can be obtained for BN@CNTs-2 based absorber when the absorber thickness is 1.6 mm. Therefore, these hildewintera-colademononis-like BN@CNT composites are expected to be used as microwave absorption materials as they are lightweight and have broad absorption bands and strong absorption with thin thickness. This facile and controllable fabrication process offers a new strategy for designing and fabricating diverse h-BN/carbon based composites for different applications.