Ultralight MXene-Coated, Interconnected SiCnws Three-Dimensional Lamellar Foams for Efficient Microwave Absorption in the X-Band

Two-dimensional (2D) few-layered TiCT MXene (f-TiCT ) has been proved to be one of the most promising electromagnetic interference (EMI) materials, but its electromagnetic (EM) absorption properties and loss mechanism have not been studied so far. Herein, for the first time, ordered lamellar f-TiCT /SiCnws hybrid foams with ultralow density are synthesized by a combination of self-assembly and bidirectional freezing processes. The freestanding foams exhibit excellent EM absorption properties superior to most of the current foam-based counterparts. The effective absorption bandwidth is always able to cover the whole X-band, when the sample thicknesses of f-TiCT /SiCnws hybrid foams distribute in any value between 3.5 and 3.8 mm, and the minimum reflection coefficient reaches -55.7 dB at an ultralow density of only about 0.029 g·cm. The fundamental mechanism associated with optimized impedance matching, enhanced polarization loss, and conductive loss is discussed in detail. Our results evidence that 2D flexible f-TiCT MXene has great potential in EM absorption field like graphene.