High performance electromagnetic wave absorbing material based on 3D flower-liked MXene

Two-dimensional transition-metal carbides (MXene) has been considered as a promising choice for outstanding EMW absorption material, because of the single dielectric loss caused by its high dielectric constant and the various polarization modes attributed to the abundant surface groups. However, the impedance mismatch caused by high dielectric constant and the structural design difficulties resulted from lamellar self-stacking limit the application of MXene. In this study, large-size MXene precipitation and small-size MXene were separated by a differential centrifugal method. A novel flower-like MXene (MXene-F) self-assembled from small-size MXene was obtained by an ice template method. The chemical compositions of MXene and its formation mechanism were analyzed by XRD, XPS, Raman and FTIR. Results showed that nano-scaled MXene could self-assemble into a spherical structure under the action of intermolecular hydrogen bonds. The porous structure of MXene-F was conducive to its impedance matching, and its flower-like structure could enhance the multiple reflection and scattering. Therefore, MXene-F possessed excellent absorption performance with a minimum reflection loss of −66.9 dB at a thickness of only 1.47 mm and an effective absorption bandwidth of 4.08 GHz. This work provides a novel and effective approach for the preparation of MXene EMW absorbing materials with low thickness and high reflection loss.