Sandwich-structured all-organic composites with high breakdown strength and high dielectric constant for film capacitor

Currently, energy storage capacitors with high breakdown strength and dielectric constant are highly desired in microelectronics and electric power systems. All-organic film capacitors have been studied owing to their high breakdown strength and low dielectric loss. In this study, poly(vinylidene fluoride) (PVDF) with high breakdown strength was used as outer layers and poly(vinylidenefluoride-ter-trifluoroethylene-ter-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) with high dielectric constant was used as the interlayer to prepare sandwich-structured composites. These PVDF/P(VDF-TrFE-CTFE)/PVDF composites with various contents of terpolymer were manufactured through a layer-by-layer solution-casting method. At 1 kHz, the maximum dielectric constant of the sandwich-structured composites reaches up to 18.61 when the content of terpolymer is 45 vol%. The discharged energy density increases with the increasing content of terpolymer at the same electric filed. At 660 kV/mm, the composite with 25 vol% terpolymer delivers the maximum discharged energy density, which is 20.86 J/cm³.