High-efficiency and wide-bandwidth microwave absorbers based on MoS₂-coated carbon fiber

Carbon fiber (CF) is a significant multifunction material, which is extensively used in aircraft because of its superb performance. However, its microwave absorption properties (MAPs) are seriously restricted as a result of the impedance mismatch issue. To address this issue, an efficient strategy is conducted by a series of CF@MoS₂ and CF@MoS₂@Fe₃O₄ composites that are fabricated by in-situ grown MoS₂ nanosheets (MoS₂-NS) and Fe₃O₄ nanoparticles (Fe₃O₄-NPs) on the surface of CF. The results of microwave absorption performance (MAP) reveal that the minimum reflection loss (RL) can reach -21.4 dB with a CF@MoS₂ composite coating thickness of 3.8 mm; the effective attenuation bandwidth (RL < -10 dB, i.e., 90% microwave energy is attenuated) is up to 10.85 GHz (7.15-18.0 GHz). From a detailed analysis, it is observed impedance mismatch is the critical limiting factor for MAPs rather than attenuation. Furthermore, for CF@MoS₂@Fe₃O₄, the MAP is strongly dependent on the level of coating of magnetic Fe₃O₄-NPs on the surface of CF@MoS₂ composites. The mechanisms underlying the superb MAP and related phenomena are investigated, opening new directions for fabricating CF-based microwave absorbers with high efficiency and wide-bandwidth. Finally, the occurrence of multi-reflection phenomena of EM waves in absorbers are critically analyzed.