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The stretched PVDF films exhibit a substantial and concurrent increase in both permittivity and breakdown strength. The microstructure–property relationship is investigated to provide guidance in PVDF polymers for high-energy storage applications.

All-organic dielectric composites are drawing increased attention owing to their high operating voltage, low loss, and superior processability. However, polymers usually possess a relatively lower dielectric constant than most the other dielectrics, which seriously suppresses the improvement of their energy density. In this work, multilayer-structured composites with excellent dielectric and energy storage properties are prepared by the stacking method, and the effect of layer numbers on the performance of the composites is studied. High-κ polymers such as poly(vinylidenefluoride) (PVDF) and poly(vinylidenefluoride-ter-trifluoroethylene-ter-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) are used to prepare the composites with different layers. It is found that the dielectric constant is up to 14.45 at 1 kHz, which is increased with the volume fraction of the P(VDF-TrFE-CTFE) layer and layer number of the composites. Due to the increased dielectric constant, an ultrahigh discharge energy density of 18.12 J/cm 3 is achieved at the electric field of 620 kV/mm. This study exhibits an effective routine to prepare flexible high-performance dielectric materials.

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