Lightweight aramid nanofibers/carbon nanotubes/MnFe2O4 composite aerogel for highly efficient microwave absorption

With the booming development and wide applications of modern communication technology, wearable devices are becoming more and more popular in our life. Meanwhile, the pollution and radiation of electromagnetic wave (EMW) is becoming increasingly prominent and threating to human health, equipment operation and military security. Multi-component regulation and spatial microstructure design of microwave absorption materials is an effective strategy for solving the pollution and radiation of electromagnetic wave. Herein, aramid nanofibers/carbon nanotubes/MnFe2O4 (ACF) composite aerogel were prepared through the combination of freeze-drying technique and hydrothermal method. Impedance matching of aramid nanofibers/carbon nanotubes aerogel is improved by introducing MnFe2O4 particles, inducing to that EMW is more easily incident into aerogel and then attenuated by microwave absorber. In addition, the three-dimensional networks structure of aerogel can enhance the multiple reflection and scattering, and improve the loss capacity of EMW. ACF05 aerogel exhibits a minimum reflection loss of −64.6 dB at 12.0 GHz and broad effective absorption bandwidth of 5.0 GHz under thickness of 2.1 mm. The excellent microwave absorption (MA) performance of ACF aerogel mainly comes from the synergistic effect of three-dimensional networks structure, impedance matching, dielectric loss and magnetic loss.