In this study, we report the effect of intercalation of dimethyl sulfoxide (DMSO) and urea molecules into the interlayer space of Ti₃C₂T_x MXene on the dielectric properties of poly(vinylidene fluoride) (PVDF)/MXene polymer nanocomposites. MXenes were obtained by a simple hydrothermal method using Ti₃AlC₂ and a mixture of HCl and KF, and they were then intercalated with DMSO and urea molecules to improve the exfoliation of the layers. Then, nanocomposites based on a PVDF matrix loading of 5–30 wt.% MXene were fabricated by hot pressing. The powders and nanocomposites obtained were characterized by using XRD, FTIR, and SEM. The dielectric properties of the nanocomposites were studied by impedance spectroscopy in the frequency range of 10²–10⁶ Hz. As a result, the intercalation of MXene with urea molecules made it possible to increase the permittivity from 22 to 27 and to slightly decrease the dielectric loss tangent at a filler loading of 25 wt.% and a frequency of 1 kHz. The intercalation of MXene with DMSO molecules made it possible to achieve an increase in the permittivity up to 30 at a MXene loading of 25 wt.%, but the dielectric loss tangent was increased to 0.11. A discussion of the possible mechanisms of MXene intercalation influence on the dielectric properties of PVDF/Ti₃C₂T_x MXene nanocomposites is presented.

The development of new electrode materials for electrochemical systems for various purposes is a significant and in-demand task of scientific research. Layered transition metal carbides and nitrides, known as MXenes, show great potential for use as electrodes in electrochemical energy storage devices operating in aqueous electrolytes. In this work, a multilayer Ti₃C₂T_x MXene was obtained from a Ti₃AlC₂ precursor and studied as the electrode material of a symmetrical supercapacitor with an aqueous LiCl electrolyte. The formation of the MXene structure was confirmed by the data from X-ray phase analysis and scanning electron microscopy. The X-ray diffraction pattern showed the disappearance of the main reflections related to the Ti₃AlC₂ phase and the shift of the reflection peak (002) from 9.4° to 6.7°, which indicated successful etching of the Al layers from the Ti₃AlC₂ precursor. At electrolyte concentrations of 1, 5, 10, and 20 M, the supercapacitors demonstrated high specific capacitances of 105, 120, 126, and 151 F·g⁻¹ at a scan rate of 5 mV·s⁻¹. In addition, an increase in the LiCl concentration contributed to the expansion of the potential window from 0.7 to 1 V. It was shown that the contribution of the surface capacitance to the total capacitance of the electrode is about 40% and depends little on the scan rate. In addition, the symmetrical supercapacitor with 5 M electrolyte showed good cyclic stability with capacitance retention of 88% over 10,000 cycles. The parameters of the main components of the physical processes of supercapacitors based on Ti₃C₂T_x were determined by the method of impedance spectroscopy.

New three-phase composites, destined for application as dielectrics in the manufacturing of passive elements of flexible electronics, and based on polymer (PVDF) matrix filled with powdered ceramics of the hollandite-like (KFTO(H)) structure (5.0; 7.5; 15; 30 vol.%) and carbon (MWCNT) additive (0.5; 1.0; 1.5 wt.% regarding the KFTO(H) amount), were obtained and studied by XRD, FTIR and SEM methods. Chemical composition and stoichiometric formula of the ceramic material synthesized by the sol–gel method were confirmed with the XRF analysis data. The influence of the ceramic and carbon fillers on the electrical properties of the obtained composites was investigated using impedance spectroscopy. The optimal combination of permittivity and dielectric loss values at 1 kHz (77.6 and 0.104, respectively) was found for the compositions containing K_1.6Fe_1.6Ti_6.4O₁₆ (30 vol.%) and MWCNTs (1.0 wt.% regarding the amount of ceramic filler).

In this study, two-dimensional V₂CT_x MXenes were prepared by an accessible and rapid method, which involved aluminothermic combustion synthesis of the V₂AlC MAX phase and its further processing in an HCl/LiF mixture under hydrothermal conditions.