Enhanced low-frequency microwave absorbing property of SCFs@TiO₂ composite

It has been rarely reported that the microwave absorption materials can exhibit excellent low-frequency EM wave absorbing properties. In this paper, we synthesized steady short carbon fibers (SCFs)@TiO₂ composites by using simple one-pot hydrothermal process. The conductive short carbon fibers could be separated by TiO₂ nanoparticles from each other and reduced the conductivity of composite materials as a whole, meeting the requirements of impedance matching. With the introduction of SCFs content, SCFs@TiO₂ composites showed improved tanδ_E values at low frequencies, implying the enhanced microwave attenuation ability at low and medium frequency. We unexpectedly found that the SCFs@TiO₂ composites exhibited very strong absorbing peaks (i.e., −46.3 dB) at low frequencies with relatively thin matching thickness. Interestingly, when the thickness of the SCFs@TiO₂ composite was only 1.0 mm, the absorbing bandwidth with a RL value less than −10 dB was over 14.3–16.7 GHz (i.e., absorbing frequency bandwidth is 2.4 GHz).