Sulfur-Doped MXene-Based Nanocomposites for Efficient Electromagnetic Wave Absorbers via Polarization and Magnetization

Ti3C2T (x) (MXene)materials with multilayered structures have been widely investigatedas promising absorption materials. However, the electromagnetic waveabsorption performance of a single Ti3C2T (x) MXene has always been limited by interfacemismatches due to high reflectivity. In this work, sulfur-doped MXene-basednanocomposites were constructed by a mild doping and calcination methodand performance was regulated by manipulating chemical composition,loading ratio, electromagnetic parameters, or impedance matching.Here, sulfur-doped MXene and titanium dioxide produced via high-temperaturecalcination (S-MXene (TiO2)) provided abundant defectsand functional groups, resulting in dipole polarization relaxation.The introduction of Ag improved the electrical conductivity, and theCoNi alloy could enhance the magnetic loss and improve impedance matching.The electromagnetic wave absorption ability was enhanced thanks tothe combined effects of suitable conductivity, dipole polarization,interface polarization, and magnetic loss. The S-MXene (TiO2)/Ag/CoNi nanocomposites exhibited a high reflection loss of -63.1dB at a thickness of 2.1 mm and a wide effective absorption bandwidthof 5.2 GHz at a thickness of 2.0 mm. Moreover, by adjusting the massratio of nanocomposites' components, the minimum reflectionloss value was up to -80.9 dB at only 1.5 mm. This mechanismof increasing material loss through doping is of great significancefor improving the electromagnetic wave absorption of MXene-based nanocomposites.