Dielectric Properties of Flexible Poly(vinylidene fluoride) Nanocomposite Films with Two-Dimensional Nb2CTx MXene Filler

Two-dimensional transition metal carbides (MXenes) have shown great promise for developing flexible polymer nanocomposites with high dielectric constant. A critical challenge lies in balancing high dielectric constant with low dielectric loss, which is governed by the electrical conductivity of the nanofiller. This study investigates two-dimensional Nb2CTx MXene as a promising low-conductivity filler for achieving this balance. Nanocomposites of poly(vinylidene fluoride) (PVDF) containing 5–30 wt.% Nb2CTx were prepared and characterized by x-ray diffraction, scanning electron microscopy, and simultaneous thermal analysis (TGA-DSC). The dielectric properties were studied by impedance spectroscopy over a temperature range from −50°C to 130°C. The nanocomposite with 30 wt.% Nb2CTx exhibited a high dielectric constant (ε’ ≈94) with a concurrently low dielectric loss tangent (tan δ ≈0.2) at 10 kHz. While the dielectric constant values were comparable to those of nanocomposites with previously studied MXene fillers, such as Ti3C2Tx or V2CTx, the dielectric losses were significantly lower, highlighting the advantage of the two-dimensional Nb2CTx filler. The temperature-dependent dielectric response was primarily dominated by the PVDF matrix, regardless of filler concentration. These findings underscore the potential of two-dimensional Nb2CTx MXene for designing advanced flexible dielectric films with tailored dielectric properties. © 2025 Elsevier B.V., All rights reserved.