High energy density of polymer nanocomposites at a low electric field induced by modulation of their topological-structure

Abstract

Polymer nanocomposite dielectrics are of critical importance for a number of electrical and electronic applications. It is highly desirable to achieve high energy density at a low electric field. In this contribution, PVDF-based (or PVDF–TrFE–CFE based) nanocomposite films filled with BaTiO₃@TiO₂ nanofibers are cast from solutions. Topological-structure modulated polymer nanocomposites are assembled layer-by-layer with the as-cast films via a hot-pressing process. Modulation of the topological-structure induces substantial redistribution of the local electric field among the constituent layers, giving rise to enhanced electric polarization at a low electric field and increased breakdown strength. These synergistic effects lead to an ultrahigh energy density of ∼12.5 J cm⁻³ and a high discharge efficiency of ∼70% at 350 kV mm⁻¹. High energy density at a low electric field is thus achieved by modulating the topological structure of polymer dielectric nanocomposites, which is of critical significance to make dielectric nanocomposites viable energy storage devices.