Ultralight and flexible SiC nanoparticle-decorated carbon nanofiber mats for broad-band microwave absorption

Light-weight and flexible microwave absorbers are in increasing demand because of the electromagnetic (EM) pollution. Carbon fiber mats are promising as they have high flexibility and conductivity. However, the high permittivity of the carbon fibers leads to a strong impedance mismatch with free space. Thus, SiC was introduced to carbon fibers as it has an outstanding impedance match with free space. After the decoration of SiC nanoparticles, incident microwaves could penetrate into the SiC decorated carbon (C-SiC) nanofiber mats and be converted into internal energy instead of being reflected. Conductive loss and polarization relaxation loss from the SiC nanoparticles and conductive carbon nanofiber matrix consumed the EM energy. Additionally, the highly flexible carbon fiber matrix could bear the load of bending and twisting, leading to excellent flexibility and reliability. The C-SiC nanofiber mats exhibited a resistance change less than 20% after 200 times bending, and had excellent EM absorbing properties with the RLmin of -53.7 dB at the thickness of 2.15 mm and the effective bandwidth of 7.11 GHz at the thickness of 2.6 mm. The proposed strategy may facilitate the design of highly reliable and flexible carbon based two dimensional (2D) EM absorbers for the broadband wave absorbing. (C) 2020 Elsevier Ltd. All rights reserved.