Abnormal high voltage resistivity of polyvinylidene fluoride and implications for applications in high energy density film capacitors

Polyvinylidene fluoride (PVDF) based fluoropolymers are promising materials for capacitors in pulsed power applications because of their high dielectric constant compared to other polymers. High energy losses, such as conduction losses or ferroelectric losses, impose great challenges for large-scale commercialization. Here, we present a systematic study on the high field electrical conduction of biaxially oriented PVDF films. The conductivity shows a surprising initial decrease, followed by a gradual increase, with increasing electric field. The unexpected decrease in conductivity arises from ferroelectric switching, and the electric field of the transition point in conductivity is consistent with the switching field for polarization reversal. This suggests that PVDF films with pre-aligned ferroelectric domains could simultaneously exhibit reduced high field conduction losses and ferroelectric losses.