Surface Size- and Structure-Optimized Design of Two-Dimensional MXene Nanosheets for Electromagnetic Wave Absorption

Abstract

As a two-dimensional material, Ti3C2Tx-Mxene nanomaterial has been extensively studied for its applications in electromagnetic wave absorption (EMI) due to its extremely high surface area, excellent hydrophilicity, and metallic-like conductivity. However, the surface size and sandwich structure of two-dimensional (2D) MXene nanomaterials are the key factors affecting their absorption properties, but no studies have been carried out. Therefore, in this work, a single layer of Ti3C2Tx-Mxene nanosheet material is fabricated by modification and its physical properties are characterized and analyzed. Then, the absorption properties of monolayers Ti3C2Tx-Mxene nanomaterials with different surface sizes are investigated both by numerical simulations and experiments, respectively, and surface sizes are optimized by orthogonal tests. Finally, the interlayered two-dimensional Ti3C2Tx-Mxene nanomaterials are optimized by particle swarm optimization (PSO) algorithm based on nanometer and millimeter size space. The results show that the best wave absorption performance is achieved with a surface size of 0.8 μm length and 0.6 μm width, resulting in a reflectivity of −98.59 dB. When ethanol is used as the matching material in the middle layer, the sandwich structure has better absorption properties than the air layer. The reflectivity of the PSO-optimized 2D Ti3C2Tx-Mxene sandwich structure in the nanometer size is observed in the range of −109.58 to −90.43 dB in the frequency range of 2–18 GHz. In addition, the reflectivity on the millimeter size fluctuates between −2.9 and −28.86 dB in the frequency range of 2–18 GHz, and the effective absorption bandwidth reaches 7.21 GHz. The optimized material shows the characteristics of low reflectivity and wide effective absorption frequency band, indicating that the optimized surface size and sandwich structure can better enable Ti3C2Tx-Mxene nanosheets to be applied to ethylene methyl acrylate (EMA) materials.