Modulation of layer thickness-dependent dielectric polarization of Ti₃C₂T_x MXene through moderate ultrasonic cavitation effect and water molecule intercalation

Two-dimensional MXene materials have garnered widespread attention in the fields of electromagnetic wave (EMW) absorption, owing to their exceptional electrical conductivity, structural versatility, and inherent hydrophilicity. In this study, we design a mild exfoliation strategy, specifically controlling the ultrasonic temperature and duration to exfoliate middle multi-layer Ti₃C₂T_x MXene materials through cavitation effect and water molecules intercalation, obtaining Ti₃C₂T_x MXene materials with varying layer thicknesses, which are expected to serve as excellent EMW absorption materials. The dipolar relaxation polarization provided by surface terminal groups (−F, −OH, −O) and polar water molecule (H₂O), the interface polarization formed between layers, and the transition from interface polarization to conduction loss driven by the nanosheet thickness and size, all contribute to the exceptional EMW properties. Finally, the 25 °C-3 h sample reaches a minimum reflection loss (RL_min) of −41.01 dB, corresponding to an effective absorption bandwidth (EAB) of 4.64 GHz. The radar cross section (RCS) simulation validates the feasibility of the material in practical scenarios, giving the values of RCS_min and RCS_ave as 0.16 and –28.80 dB·m². Simulations conducted on a JF-17v1 fighter result in an effective radar stealth performance. This work proposes a mild exfoliation strategy for Ti₃C₂T_x MXene materials and develops ultra-light aerogels with excellent wave-absorbing properties and radar stealth effects, aiming to expand their potential for future practical applications.