Simultaneously enhanced energy density and discharge efficiency of layer-structured nanocomposites by reasonably designing dielectric differences between BaTiO₃@SiO₂/PVDF layers and BNNSs/PVDF-PMMA layers

The enhancement of the energy density and efficiency for polymer-based nanocomposites is advantageous for promoting their practical application in miniaturization and integration of dielectric capacitors. In this work, a class of newly designed layer-structured polymer-based nanocomposites based on BaTiO₃@SiO₂/PVDF dielectric layer as the central layer and BNNSs/PVDF-PMMA layers as the outer layers were prepared. By reasonably adjusting the dielectric properties of a BaTiO₃@SiO₂/PVDF dielectric layers and BNNSs/PVDF-PMMA insulating layers, the layer-structured nanocomposites exhibits simultaneously high discharge density of 20.1 J/cm³ and high efficiency of 76% under an electric field of 507 MV/m. A series of dielectric analyses and simulation results indicate that the appropriate dielectric differences redistribute the electric filed in the layer-structured nanocomposites, which relieves the electric field strength in the dielectric layer and enhances the electric breakdown strength of nanocomposites. This work can provide an effect strategy to design polymer-based nanocomposites with significantly energy storage performance.