Core-shell N-doped carbon nanofibers@poly(3,4-ethylenedioxythiophene): Flexible composite fibers for enhanced electromagnetic wave absorption

• The core-shell N-doped carbon nanofibers@poly(3,4-ethylenedioxythiophene) (NCNFs@PEDOT) flexible composite fibers with dual three-dimensional network were constructed. • The electromagnetic wave absorption performance and mechanism were analyzed in detail. • The maximum reflection loss reached -66.9 dB (NCNFs@PEDOT-10%), and the maximum effective absorption bandwidth reached 6.72 GHz (NCNFs@PEDOT-5%). • The radar cross section values of multilayer composites under two arrangements were simulated. The conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) is uniformly coated on the surface of N-doped carbon nanofibers (NCNFs) to construct NCNFs@PEDOT flexible composite fibers with dual three-dimensional conductive networks. The prepared samples are mixed with paraffin at different mass ratios (2%, 5%, 10%, 15%), NCNFs@PEDOT-10% exhibits a maximum reflection loss (RL) of -66.9 dB at 2.6 mm, while NCNFs@PEDOT-5% shows a maximum effective absorption bandwidth (EAB) of 6.72 GHz at 2.7 mm. The excellent electromagnetic (EM) wave absorption performance is attributed to the conduction loss in the conductive network; the interfacial polarization between NCNFs and PEDOT; and the dipole orientation polarization caused by N atom doping and graphite structural defects. Furthermore, the radar cross section (RCS) values of multilayer composites with positive and negative conductivity gradients are simulated. This work provides a reference for the research of flexible EM wave absorbers and the structural design of multilayer EM wave absorbing materials.