Two-dimensional Ti3C2Tx/carbonized wood metacomposites with weakly negative permittivity

In recent years, random composites with negative permittivity have been widely concerned owing to their unique properties and broad application prospects. In this paper, Ti3C2Tx/carbonized wood (CW) composites with weakly negative permittivity were prepared by using CW as matrix and two-dimensional layered Ti3C2Tx as the functional filler. The results of dielectric properties indicated that when the content of Ti3C2Tx was 42.5 wt%, three-dimensional conductive networks were formed universally on the surface and inside the CW matrix. Meanwhile, the conduction mechanism changed from jumping conduction to metal-like conduction. Besides, the permittivity values of Ti3C2Tx/CW composites changed from positive to negative and significantly reduced to the range of −65 to −35. This unique phenomenon was owing to the total electron concentration in the Ti3C2Tx/CW composite being diluted equivalently, resulting in the decrease of plasma frequency, thus showing a weakly negative permittivity. This work provides a new strategy to determine the suitable content of conductive filler using percolation theory. Furthermore, the original fantastic structure properties of Ti3C2Tx and wood also opened a new way for designing metacomposites, which has very important research value and far-reaching research significance.Graphical abstractWeakly negative permittivity achieved in two-dimensional Ti3C2Tx/carbonized wood metacomposites.