One-dimensional barium titanate coated multi-walled carbon nanotube heterostructures: synthesis and electromagnetic absorption properties

Abstract

One-dimensional barium titanate (BaTiO₃)@multi-walled carbon nanotube (MWCNT) core–shell heterostructure composites are prepared via a sol–gel route combined with a thermal treatment process. Field emission scanning electron microscopy and transmission electron microscopy measurements show that the BaTiO₃@MWCNT core–shell heterostructure composites have a BaTiO₃ film thickness of ∼10 nm, and that the BaTiO₃ film uniformly encapsulates the surface of the MWCNT core. The measured electromagnetic parameters show that the BaTiO₃@MWCNT composites exhibit remarkable and improved electromagnetic wave absorption properties, compared to both pristine MWCNTs and BaTiO₃. Notably, more than 99% of electromagnetic wave energy can be attenuated by the BaTiO₃@MWCNT composites with the addition of only 40 wt% in the paraffin matrix. In addition, the microwave absorption mechanism of the BaTiO₃@MWCNT core–shell heterostructure composites is proposed. The various polarizations including dielectric and interfacial polarization which originate from the heterogeneous structures and interfaces in the composites are responsible for their excellent microwave absorbing performances.