Electrical properties and applications of carbon nanotube composites

Many types of electromagnetic (EM) absorbers have been developed to convert EM energy into heat and to absorb EM waves. However, multilayer EM absorbers are complicated to design, fabricate and dispose of. In this work, we present a simple and scalable design method to achieve a single-layer electromagnetic absorber with a high absorption coefficient in a wide range of frequency bands. On the basis of the design, we develop two types of non-woven fabrics with high porosity in which the fibres are coated with multi-walled carbon nanotubes (MWCNTs). The absorption coefficients exceed 0.9 for the 5-mm-thick MWCNT-coated non-woven fabric measured in the 50-67 GHz range. An absorption coefficient of 0.94 at 5.8 GHz is expected to be obtained by using 50-mm MWCNT-coated fabric with a lower MWCNT content. The present MWCNT-coated non-woven fabrics will be useful materials for high-performance EM absorbers.