Enhanced electromagnetic wave absorption via optical fiber-like PMMA@Ti₃C₂T_x@SiO₂ composites with improved impedance matching

Ti3C2Tx nanosheets have attracted significant attention for their potential in electromagnetic wave absorption (EWA). However, their inherent self-stacking and exorbitant electrical conductivity inevitably lead to serious impedance mismatch, restricting their EWA application. Therefore, the optimization of impedance matching becomes crucial. In this work, we developed polymethyl methacrylate (PMMA)@Ti3C2Tx@SiO2 composites with a sandwich-like core-shell structure by coating SiO2 on PMMA@Ti3C2Tx. The results demonstrate that the superiority of the SiO2 layer in combination with PMMA@Ti3C2Tx, outperforming other relative graded distribution structures and meeting the requirements of EWA equipment. The resulting PMMA@Ti3C2Tx@SiO2 composites achieved a minimum reflection loss of -58.08 dB with a thickness of 1.9 mm, and an effective absorption bandwidth of 2.88 GHz. Mechanism analysis revealed that the structural design of SiO2 layer not only optimized impedance matching, but also synergistically enhanced multiple loss mechanisms such as interfacial polarization and dipolar polarization. Therefore, this work provides valuable insights for the future preparation of high-performance electromagnetic wave absorbing Ti3C2Tx-based composites.