Tuning the Energy Storage Efficiency in PVDF Nanocomposites Incorporated with Crumpled Core–Shell BaTiO₃@Graphene Oxide Nanoparticles

Ferroelectric poly(vinylidene fluoride) (PVDF)-based polymer nanocomposites have garnered considerable attention for film capacitor applications. However, the addition of highly polarized inorganic fillers with a large proportion into PVDF leads to poor processability and high energy loss, which significantly destroy the structural integrity of the film and restrain the practical application of film capacitors. Herein, we constructed core–shell BaTiO3 (BTO)@graphene oxide (GO) architectures via an aerosolization method and incorporated them into the PVDF matrix, which not only provided a highly insulating GO layer to improve the breakdown strength and suppress the dielectric loss but also improved the dispersion of fillers to realize a high interfacial interaction. The 0.4 wt % BTO@GO/PVDF film exhibited a high discharged energy density of 2.9 J cm–3 at 200 MV m–1, 70% higher than that of the PVDF film, a charge–discharge efficiency of 86%, and a depressed dielectric loss of 0.07 at 1 kHz. Moreover, the ultralow content of fillers can greatly improve the processability and reduce the defects with the structural integrity as well as the performance stability of the film during stretching. This work sheds light on the improvement of energy storage performance of polymer nanocomposites for film capacitors.