Two‐dimensional Ti₃C₂T_x/poly(vinylidene fluoride) metacomposites with weakly negative permittivity

Abstract In recent years, random metacomposites with tunable negative permittivity have aroused widespread attention because of their distinctive properties and broad potential prospects. It is indicated that an enormously negative permittivity with a large value is not conducive to performance optimizing and impedance matching. In this article, the 2D Mxene Ti₃C₂T_x was selected as the conductive phase instead of metal and carbon materials to fabricate Ti₃C₂T_x/poly(vinylidene fluoride) metacomposites. The results of dielectric properties indicated that the conductive Ti₃C₂T_x networks were formed by Ti₃C₂T_x contacting with each other near the percolation threshold (ƒ_c). The as‐obtained metacomposites containing 75 wt% Ti₃C₂T_x generated percolating phenomenon. Additionally, when the fraction of Ti₃C₂T_x was below ƒ_c, the frequency dispersion behaviors of conductivity were in accordance with the Jonscher's power law, which proved that conducting mechanism was dependent on hopping conduction. While above ƒ_c, the conductivity conformed to the Drude model and Lorentz model, which demonstrated a conductive behavior. Furthermore, the real part of permittivity transformed to negative value at 75 wt%, which can be explained as the existence of the low‐frequency plasma oscillation and electric‐dipole‐induced resonance. The dielectric loss of the metacomposite was also analyzed by the imaginary permittivity spectra. Small negative permittivity values in the range of −550 to −400 were observed, owing to the low free carrier concentration in composites. The appearance of weakly negative permittivity opened up a new direction in negative dielectric materials by 2D layered Ti₃C₂T_x nanomaterials.