Layered composites composed of multi-walled carbon nanotubes/manganese dioxide/carbon fiber cloth for microwave absorption in the X-band

In this paper, multi-layered composites are fabricated for their application in electromagnetic interference (EMI) shielding. Composites of multi-walled carbon nanotubes/manganese dioxide (MnO 2 )/epoxy are used as a microwave absorption layer, and a commercial carbon fiber cloth is used as a reflection layer. When the electromagnetic (EM) waves impinge on such layered composites, the absorption layer can absorb most of the EM waves, and the transmitted EM waves from the absorption layer will be reflected back by the reflection layer and absorbed by the absorption layer. Based on the rational design, the composites with four absorption layers and one reflection layer (with a total thickness of 2.85 mm) show a high EMI shielding effectiveness of 41.24 dB, while the average reflection loss of 13.62 dB can be attained in the X-band (8.2-12.4 GHz). Moreover, the layered composites can absorb nearly 95% of the EM waves at the operating frequency, and provide an absorption dominant EMI shielding which are favorable for commercial and military applications. Multi-layered composites of MWCNTs/MnO 2 /epoxy show high microwave absorption ability due to interface reflection and synergetic effects of MWCNTs and MnO 2 .