Ultrathin ceramic nanowires for high interface interaction and energy density in PVDF nanocomposites

Abstract Dielectric nanocomposites with ceramic fillers have a crucial role in energy storage applications. Therefore, poly(vinylidene fluoride) ( PVDF ) based nanocomposites filled with 20 nm diameter, surface hydroxylated BaTiO ₃ nanowires ( BT nws) were produced by solution‐casting method in this work, in which BT nws were synthesized via solvothermal method. The dielectric constant of BT nws/ PVDF nanocomposites was 24 when the content of fillers was 10vol% at 100 Hz and the breakdown strength could increase up to 417 kV/mm before decreasing. The nanocomposites showed enhanced energy density performance and the maximum energy density could reach to 8.1J/cm ³ at 320 kV/mm with 10vol% BT nws, nearly tripled that of pure PVDF at 300 kV/mm. Finite element and molecular dynamic simulation results revealed that thin BT nws could create dielectric homogeneity in the nanocomposites and have strong interface interaction with PVDF molecular. The ultrathin BT nws provided the possibility that single PVDF molecular could wrap on its surface, but this molecular wrapping pattern would not occur when the diameter of BT nws was large. Besides, the wrapping pattern could be reinforced by interactions between surface hydroxyl groups of BT nws and F atoms of PVDF molecular. Such contributions could induce good interface compatibility and lead to the improvement of energy density.