Enabling High Dielectric Response in PVDF/V₂C MXene–TiO₂ Composites Based on Nontypical V–F–Ti Bonding and Fermi-Level Overlapping Mechanisms

Abstract

High dielectric constant and breakdown strength are crucial for high-energy-density polymer/ceramic composites. Anatase-TiO2 with low dielectric constant and V2C MXene with high work function are not satisfactory fillers. In the present work, V2C–TiO2 hybrid filler was in situ synthesized, followed by fabricating poly­(vinylidene fluoride) (PVDF)/V2C–TiO2 composites via solution cast. Compared with PVDF/TiO2 and PVDF/V2C composites, PVDF/V2C–TiO2 composites have an improved high dielectric constant, depressed low dielectric loss, and maintained high breakdown strength. High overall electric traits are ascribed to the synergy of conductive V2C and semiconductive TiO2. Outer and inner surfaces of V2C were ornament-combined by anatase-TiO2 particles having surface point defects as electron traps, contributing to low interface leakage conduction. Through density functional theory (DFT) calculations, nontypical V–F–Ti-bonding-induced dipole enhancement and Fermi-level (E F) overlapping-induced high electron localization mechanisms improve the dielectric response. Ternary composite with 10 wt % hybrid filler exhibits a dielectric constant of ∼99, a dielectric loss of ∼0.24 at 1 kHz, and a breakdown strength of ∼189 MV/m. This work might enable large-scale preparation of promising polymer/MXene composite dielectrics.

Composite of two‐dimensional vanadium carbide MXene and cellulose nanocrystals for detection of analytes

“…[13] It was observed that for the V 2 C sample, a strong peak that appears at 2θ $ 7.5 corresponds to the 002 plane. [17,28] When V 2 AlC was exposed to the LiF/HCl mixture during synthesis, the 002 peak of V 2 AlC shifted to lower 2θ angles. The shift of the 002 peak from 13.5 to 7.5 corresponds to a dspacing increase from $6.58 to $11.8 Å.…”

“…The PVDF/V 2 C‐TiO 2 composite has been used to show an improved dielectric constant. [ 17 ] In this regard, cellulose nanofibers (CNFs) are considered as an ideal material for the development of environmentally friendly composites. [ 18 ] Properties like renewability, sustainability, and biocompatibility make CNF a potential candidate for various applications.…”

Multifunctional Ternary Composites with Silver Nanowires and Titanium Dioxide Nanoparticles for Capacitive Sensing and Photocatalytic Self-Cleaning Applications

“…Thus, carbon nanotubes (CNTs), 14,15 graphene, 15,16 or carbon black 17,18 are used for mechanical reinforcement and for increasing the electrical conductivity; ionic liquids 19,20 are used to improve the ionic conductivity or induce a thermochromic response, for example; magnetic nano-and microparticles 21,22 are used to induce a magnetic response to the polymer matrix; and metal−organic frameworks 23,24 mechanical or dielectric properties and absorption capabilities, among others. Many advances have been achieved in the enhancement of the dielectric response, 25 electrochemical properties, 26 and electrical conductivity 27 in PVDF-based composites. However, these studies mainly focus on improving or inducing a single functionality in the sample.…”

“…Many advances have been achieved in the enhancement of the dielectric response, electrochemical properties, and electrical conductivity in PVDF-based composites. However, these studies mainly focus on improving or inducing a single functionality in the sample.…”

Sandwich-Structured Polymer Composites with Core–Shell Structure BaTiO3@SiO2@PDA Significantly Enhanced Breakdown Strength and Energy Density for a High-Power Capacitor

“…The continuous development of electric vehicles, defense industry, and smart grids have caused high energy storage devices to attract more and more attention. − Among various energy storage methods, polymer film capacitors have become the ideal type due to their inherent mechanical properties, ease of processing, low cost advantages, and excellent dielectric properties. , Since the polymer film stores and releases energy by static polarization and depolarization, it has the advantages of high charge–discharge efficiency and environmental protection. − However, the dielectric constant of dielectric materials used in commercial film capacitors is usually low, such as 2.25 for biaxially oriented polypropylene (BOPP), which results in a low discharge energy density of only 3 J/cm 3 . Therefore, the preparation of thin film materials with high permittivity and breakdown strength has been a hotspot and nodus recently.…”