Selective localization of carbonized polymer dots in amorphous phase towards high breakdown strength and energy density of PVDF-based dielectric composites

In a general way, there is a contradictory between dielectric constant () and breakdown strength () in dielectric materials, and improving the discharge energy density () of dielectric polymers has become a great challenge. The semicrystalline ferroelectric polymer polyvinylidene fluoride (PVDF) is favored for its high , but its relatively weak in amorphous regions makes it still difficult to obtain appreciable . In response to the fact that the current method of introducing rigid chain amorphous polymers into the amorphous regions of PVDF has limited capability to enhance its , in this work, due to the crystallization induced phase separation, carbonated polymer dots (CPDs) as well as PMMA were introduced into the amorphous region of PVDF, and CPDs/PVDF/PMMA composites were prepared towards high and . It is confirmed that, CPDs significantly increase the entanglement density of molecular chains in amorphous regions of PVDF; in addition, CPDs rely on their inorganic carbon cores with unique electrical properties to resist carrier migration in amorphous regions of PVDF under high electric fields. In brief, CPDs are used as a reinforcing agent for the amorphous region of PVDF to further enhance its and . The composite loaded with 0.1 wt% CPDs exhibits the superior of 12.4 J/cm3 at the of 652.0 MV/m. This work provides new understanding on the dielectric response of ultrasmall-sized CPDs on polymer dielectrics, which could help us design new dielectric polymer composites with suppressed segmental motions for high breakdown strength and high energy density applications.