Surface engineering strategy for MXene to tailor electromagnetic wave absorption performance

The emerging two-dimensional material, Ti3C2Tx MXene, has attracted significant attention in the realm of electromagnetic wave absorption owing to its exceptional inherent conductivity and distinctive microstructure. However, similar to other conductive materials, MXene encounters the challenge of impedance mismatch, thereby impeding the electromagnetic wave absorption capability in single-component MXene materials. In this study, a molten chlorine-salt method was employed to gain MXene samples with varying surface-chlorine/ oxygen (Cl/O) ratios by surface engineering. Notably, among these samples, Cl/Ni-MX-6 exhibited an impressive minimum reflection loss value of -45.72 dB (1.6 mm) and an effective absorption bandwidth of 3.44 GHz (1.3 mm). This study revealed that increasing the etchant content enhances the delamination effect of MXene and leads to adjust Cl/O ratio. Importantly, the modulation of -Cl/O surface functional groups can limit the electronic conductivity, while the number and species of different kinds of surface dipoles will control the polarization effect, ultimately optimizing the electromagnetic wave absorption performance of pure MXene. These insights contribute to ongoing efforts aimed at enhancing the performance of MXene-based materials in the field of electromagnetic wave absorption as well as get a better understanding of the electromagnetic loss mechanism.