Interfacial electronic properties of ferroelectric nanocomposites for energy storage application

Abstract

The integration of ferroelectrics and organic polymer has been showing potential in the dielectric energy storage application. To explore the interfacial interaction mechanism of PVDF-HFP/BaTiO3 nanocomposites, first-principles calculations were performed. Significant charge transfer and redistribution were observed at PVDF-HFP/BaTiO3 interfaces. BaO-terminated BaTiO3/PVDF interface (Interface-I) showed large Ti ionic displacement along the direction vertical to interfaces, while TiO2-terminated BaTiO3/PVDF interface (interface-II) showed large Ti ionic displacement along the direction parallel to interfaces. The interfacial polarization of Interface-I along the direction vertical to the interface is higher than that of interface-II, while the interfacial polarization of interface-II along the direction parallel to the interface is higher than that of interface-I. The formation mechanism of the interfacial interaction of BaTiO3/PVDF-HFP interfaces is analyzed. From analysis of density of states, the appearance of PVDF-HFP at the interfaces induced the hybridization among Ti 3d, O 2p, C 2p and F 2p orbitals at the interface, which increased the bandgap on the topmost layer, clarifying the formation mechanism of the interface reconstruction, charge distribution, ionic displacement and interfacial polarization.