Triptycene improved crystallization characteristics in PVDF-based all-organic composites boosts high energy density

Abstract

Polymer composites with high breakdown strength and low loss give their potential applications in dielectric films due to the excellent energy storage performance. However, the inorganic fillers always decrease breakdown strength, impeding the enhancement of energy density and causing a drastic decline in efficiency because of the incompatibility at filler-matrix interfaces. Herein, the organic molecular triptycene (TE) was adopted as the filler to fabricate poly(vinylidene fluoride) (PVDF)-based composites. The introduction of TE significantly affects the crystallization characteristics including crystallite size and crystallinity of PVDF, and gets rid off the disadvantages caused by inorganic fillers. The PVDF/TE composites represent significant improment in dielectric properties. The PVDF-15 wt.% TE achieves the breakdown strength of 555 MV/m, and a energy density of 17.33 J/cm3 with efficiency of ~ 74 %, which is 2.81 times over pristine PVDF.