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 (ε_r) and breakdown strength (E_b) 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 ε_r of ~12.7, low tanδ of ~0.017, and exceptional E_b of ~357 kV/mm. This strategy supplies a novel paradigm for the application of fabricating dielectric films with excellent comprehensive performance.