Highly enhanced discharged energy density of polymer nanocomposites via a novel hybrid structure as fillers

Electrostatic capacitors with a high dielectric constant and breakdown strength are desired for dielectrics to achieve a higher discharged energy density. Here, we propose that an artificial polymer nanocomposite combining a novel hybrid structure of one-dimensional Ag@BaTiO3@polydopamine@Ag nanofibers (1D ABPAs) as fillers and poly(vinylidene fluoride-hexafluoropropylene) [P(VDF-HFP)] as the matrix demonstrated a remarkably comprehensive performance. A large displacement (9.84 μC cm−2 at 480 MV m−1) was observed so as to obtain a high discharged energy density (∼17.25 J cm−3) of the composite films with 3 vol% 1D ABPAs, which was 2.22-times that of pristine P(VDF-HFP) (∼7.74 J cm−3). This discharged energy density is among the highest under an equivalent electric field strength reported so far. The corresponding composite films exhibited a superior charge/discharge speed of 139 ns and excellent reliability in energy storage performance by consecutive cycling. This work could provide an effective way to design and improve the performance of polymer-based nanocomposites for capacitive energy-storage applications.