Molecular dynamics simulation of electrical properties and surface binding energy of PVDF/ BNNS composites based on ReaxFF

Dielectric capacitor is an efficient energy storage and conversion device. In order to adapt to the operation environment of high voltage, high temperature and other extreme impact, energy storage dielectric materials with excellent properties is required. Polyvinylidene fluoride (PVDF) has good high temperature resistance and dielectric properties, while boron nitride nanosheet (BNNS) has high breakdown field strength and good thermal conductivity, which is an ideal reinforced body for composite material. In this paper, PVDF was taken as the matrix, by doping different mass fraction of BNNS, PVDF matrix and different doping ratio of PVDF/BNNS composite model were built respectively. The dielectric constant and breakdown strength of each model were calculated and analyzed at different temperatures. The surface binding energy at the junction of PVDF and BNNS was calculated, so as to reveal and the micro-mechanism of doping process from the perspective of energy. The results showed that, doping BNNS in PVDF can indeed improve the energy storage performance of the composites under high temperature conditions. This study provides a theoretical basis for improving the energy storage performance of PVDF material and developing dielectric energy storage materials for high temperature applications.