Enhanced Dielectric Performance in PVDF-Based Composites by Introducing a Transition Interface

Polymeric dielectrics have garnered significant interest worldwide due to their excellent comprehensive performance. However, developing polymeric dielectric films with high permittivity (εr) and breakdown strength (Eb) and low dielectric loss (tanδ) presents a huge challenge. In this study, amorphous aluminum oxide (Al2O3, AO) transition interfaces with nanoscale thickness were constructed between titanium oxide (TiO2, TO) nanosheets and polyvinylidene fluoride (PVDF) to manufacture composites (PVDF/TO@AO). TO@AO nanosheets showed favorable dispersion in the polymer-based composites. Improved permittivity, suppressed dielectric loss, and enhanced breakdown strength were achieved by introducing AO coating with intermediate permittivity onto TO nanosheets to build a transition interface. The transition interface efficiently depressed the mobility of the charge carrier and electric conduction of the PVDF/TO@AO composites. As a result, the PVDF-based composite with 1 wt% TO@AO showed superior comprehensive performance, including high εr of ~12.7, low tanδ of ~0.017, and exceptional Eb of ~357 kV/mm. This strategy supplies a novel paradigm for the application of fabricating dielectric films with excellent comprehensive performance.