N-doped carbon nanofiber embedded with TiN nanoparticles: A type of efficient microwave absorbers with lightweight and wide-bandwidth

Abstract

In this work, TiN-embedded in N-doped carbon nanofiber (TiN/NCNF) composites were synthesized by the electrospinning method and heat treatment process subsequently. The TiN/NCNF composites possess different TiN nanoparticles (TiNNPs) content, which can acquire by tuning the percentage of TiNNPs in the polyacrylonitrile precursor solutions. The study shows that TiN/NCNF composites hold more intense and tunable electromagnetic wave (EMW) absorption capabilities, as the embedded TiNNPs with more defects lead to enhanced electrical conductivity and cause room-temperature ferromagnetic. As a result, TiN/NCNF composites can achieve the well-matched impedance and contribute to significant electromagnetic wave attenuation capabilities due to their more interfacial polarization, defect dipole relaxation polarization, enhanced conductance loss, and magnetic loss caused by the defect, resulting in excellent microwave absorbing performance. When the mass fraction of the TiN/NCNF composites (S2 sample with nominal 3 wt% TiNNPs content) was only 30% in the absorbing coating, the optimal reflection loss (RL) value was achieved in − 45.19 dB at 15.6 GHz with a thickness of 1.91 mm, corresponding efficient absorption bandwidth (RL≤−10 dB) of 4.93 GHz. This work provides a novel method of realizing lightweight, wide-bandwidth, and efficient microwave absorbing characteristics of carbon fiber absorbents, using obtained particles from defect engineering strategies as loaded ones. As may be expected, the TiN/NCNF composites would have a significant potential application prospect as microwave absorbing materials.