In this paper, the one-dimensional (1D) Al2O3 nanofibers (Al2O3 NFs), CaCu3Ti4O12 nanofibers (CCTO NFs), and core–shell CaCu3Ti4O12@Al2O3 nanofibers (CCTO@Al2O3 NFs) were prepared via electrospinning technique. The surface modification with dopamine (PDA) was employed for the above three kinds of nanofibers before being filled the PVDF matrix, which can improve their dispersion and compatibility with the matrix. The microstructure, dielectric properties, leakage current density, breakdown strength, and energy storage performance of composites with three kinds of filler, CCTO NFs/PVDF, Al2O3 NFs/PVDF, and CCTO@Al2O3 NFs/PVDF, were systematically investigated. By comparing the three composites, it can be found that energy storage density of CCTO@Al2O3 NFs/PVDF were enhanced compared to that of pure PVDF, which can be attributed to improvement of polarization and electric breakdown strength. The energy density of 8.46 J/cm3 at 340 kV/mm was obtained for 4 vol % CCTO@Al2O3 NFs/PVDF nanocomposites, which is 230% larger than that of PVDF (3.68 J/cm3 at 330 kV/mm). This study provides a method for preparing high energy storage PVDF-based composite film which can be used for the next generation of dielectric capacitors.

No abstract

No abstract

Design of core-shell structure for ceramic filler is an effective way to improve the electric insulation property of polymer matrix. However, it still faces the disadvantage of a low dielectric constant, inhibiting the increase in energy storage density. Herein, we propose an effective strategy for regulating shell thickness to induce dielectric polarization, which simultaneously improves dielectric constant and breakdown strength of polyvinylidene difluoride (PVDF)-based nanocomposite incorporated by core-shell structured BaTiO 3 @-SiO 2 (BT@SO) nanoparticles. The results show that BT@SO fillers with a moderate SiO 2 shell thickness of 15 nm and a low content of 1.0 vol% enhances dielectric constant and breakdown strength of PVDF-based nanocomposite to 14.7 and 500.5 MV/m, respectively. Compared with pure PVDF, the dielectric constant and breakdown strength of PVDF/BT@SO are increased by 82.2% and 61.3%, respectively. Comprehensively, its discharge energy density is enhanced by 352%, up to 12.2 J/cm 3 , which is attributed to the high induced polarization of charge confinement and the multi-function combined effects of SiO 2 shell as a deep trap, barrier and adsorption layer. This study provides more insight into the interface control mechanism of core-shell nanostructure, and offers a theoretical basis for designing polymer nanocomposites with high energy storage density.