MXene-Driven Metacomposites With Low-Dispersion Negative Permittivity and Epsilon-Near-Zero Properties

Metacomposite development faces significant challenges in achieving epsilon-near-zero (ENZ) permittivity within radio frequencies while overcoming severe dispersion limitations. To address this, Ti 3 C 2 T x MXene/polyimide nanocomposites were fabricated through mechanical mixing and pressure molding. By varying MXene content, a 3D conductive network was engineered, achieving electrical percolation. Below the threshold, dielectric behavior followed Debye relaxation, while above it, negative permittivity exhibited Drude-type dispersion. Notably, near the percolation threshold (∼78 vol%), ENZ properties emerged at 501 MHz with a unique Debye–Drude coexistence. Equivalent circuit analysis revealed a capacitive-to-inductive transition, further elucidating the low-dispersion behavior. This study introduces a novel Debye–Drude copolarization model, providing a theoretical framework for designing low-dispersion negative permittivity materials with broad electromagnetic applications.