The influence of crystalline transformation of Ba0.6Sr0.4TiO3 nanofibers/poly(vinylidene fluoride) composites on the energy storage properties by quenched technique

Flexible Poly(vinylidene fluoride) (PVDF) composites with high storage density have attracted considerable research interests in the past years. The dielectric and energy storage properties of PVDF composites are highly influenced by the crystalline phase. The effect of an quenched technique on the crystalline phase, dielectric constants and energy storage density in PVDF composites consisting of 2.5 vol% surface-modified Ba0.6Sr0.4TiO3 nanofibers (BST NF) by 3-aminopropyltriethoxysilane (APS) has been investigated. The results show that the untreated PVDF composites are dominated by the β-phase, while the quenched PVDF composites are primarily in the α-phase. The quenched PVDF composites containing of 2.5 vol% of APS modified BST NF exhibited energy density as high as 6.8 J/cm3 at 3800 kV/cm, which is more than 4.2 times larger than that of untreated PVDF composites. This work may provide a route for using the quenched technique to enhance the dielectric energy density in ceramic–polymer composites.