Solid-state reaction induced defects in multi-walled carbon nanotubes for improving microwave absorption properties

Abstract Dielectric polarization performance induced by the defect engineering approach has been proved to be an effective way for improving the microwave absorption property of carbon-based materials. Assisting by the solid-state reaction, the structural integrity of multi-walled carbon nanotubes (MWCNTs) would be broken along with the volume expansion and etching process of cobalt oxides. Therefore, the defects could be obtained and result in the enhancement of microwave absorption property. Ascribing to the broken wall structures, the defect-distances (LD) and concentrations (nD) have been optimized to be 9.80 nm and 3.37 × 1011 cm−2. The minimum reflection loss (RL) had reached -54.6 dB at 4.5 GHz with a thickness of 4.13 mm and the corresponding effective absorption bandwidth (EAB