Analyzing and Enhancing the Insulation and Dielectric Properties of Layered Polymer Nanocomposite

Polymer-based dielectric films are favored and widely used in important fields such as aerospace, energy vehicles, medical equipment, wind power, and photovoltaic energy systems because of their advantages, such as lightweight, green environmental protection, strong processability, and high power density. However, due to their low relative dielectric constant and low breakdown strength, they cannot meet the demand for high energy density of energy storage systems. In this work, multicomponent polymer nanocomposites with a layered structure were constructed and prepared by the solution casting method, in which PMMA, as the intermediate layer accounted for 30 vol%, and the outer layer is polyvinylidene-hexafluoropropylene (P(VDF-HFP)) with high-dielectric inorganic BaTiO3 nanoparticles (BT NPs) added. The high breakdown field strength and low electrical conductivity of PMMA, as an intermediate layer, can effectively prevent the penetration of charges. Meanwhile, the low dielectric loss suppresses the overall loss of the multicomponent polymer nanocomposites. The interfacial coupling between the BT NPs and the P(VDF-HFP) macromolecular chain in the outer layer enhances the polarization value. Moreover, improved breakdown strength was confirmed in the designed nanocomposite by a Weibull decomposition distribution. It is found that under a high electric field of 425 MV/m, the energy storage density of the nanocomposite with optimized nanofiller content (5 wt %) is increased to 15.5 J/cm3, overcoming the energy storage density in most previous references and ferroelectric polymer P(VDF-HFP). This contribution provides a practical approach that can make the polymer-based nanocomposites have excellent energy storage performance.