High Dielectric Constant and Low Dielectric Loss via Poly(vinyl alcohol)/Ti₃C₂T _x MXene Nanocomposites

As a new class of two-dimensional materials, the MXene family has triggered attention because of its unique electrical and mechanical properties. MXene's excellent electrical conductivity and hydrophilicity make it an ideal option for polymer nanocomposite fabrication. For the first time, polymer nanocomposites of polyvinyl alcohol (PVA)/Ti₃C₂T _x (MXene) were used for charge storage applications in the X-band frequency range (8.2-12.4 GHz). By implementing solution casting and vacuum-assisted filtration (VAF), flexible thin films with exceptional dielectric properties (solution casting @ 10.0 wt % MXene: ε' = 370.5 and tan δ = 0.11 and VAF @ 10.0 wt % MXene: ε' = 3166 and tan δ = 0.09) were fabricated. The reported dielectric constants in this study are among the highest values obtained in X-band frequency with low dielectric losses. This outstanding performance originates from the high electrical conductivity of synthesized Ti₃C₂T _x MXene (σ ≈ 1.4 ± 0.077 × 10⁶ S/m; the highest reported value for Ti₃C₂T _x MXene to date in the literature), great dispersion state, and the nacre-like structure of the polymer nanocomposites. Combining the exceptional properties of MXene with the effective nacre-like structure, PVA/MXene nanocomposites can be used as a novel charge storage material, fulfilling the requirements of flexible electronics and energy storage devices.