Poly(vinylidene fluoride) nanocomposites with a small loading of core-shell structured BaTiO^sub 3^@Al^sub 2^O^sub 3^ nanofibers exhibiting high discharged energy density and efficiency

BaTiO3@Al2O3 core-shell nanofibers (BT@Al2O3 NF) have been successfully synthesized. Homogeneous nanocomposites consisting of BT@Al2O3 NF and a Poly(vinylidene fluoride) (PVDF) polymer matrix have been prepared by the solution casting method. A systematic study was investigated on the effect of BT@Al2O3 NF filler introduction on the discharged energy density performance of the nanocomposite. Al2O3 shell dramatically reduces the leakage current by prevent the contact between BT NF fillers in nanocomposites and minimize the Maxwell-Wagner-Sillars interfacial polarization, which results in the enhancement of the breakdown strength of nanocomposites films. Simultaneously, the nanocomposites have higher maximum polarization and lower the remnant polarization than that of PVDF films under the same electric field. The maximum discharged energy density of the nanocomposites with 2.5 vol% BT@Al2O3 NF reaches 7.1 J/cm3 at 3800 kV/cm with an efficiency of above 65.1%. This work may provide an effective solution for enhancing the discharged energy density of nanocomposites films.