Enhanced discharged energy density and efficiency of poly(vinylidene fluoride) nanocomposites through a small loading of core-shell structured BaTiO3@Al2O3 nanofibers

Nanocomposite based on poly(vinylidene fluoride) (PVDF) polymer filled with surface functionalized core-shell structure BaTiO3@Al2O3 nanofibers (BT@Al2O3 NF) were prepared via the solution casting method. Experimental results clearly demonstrate that the nanocomposites with BT@Al2O3 NF exhibit enhanced discharged energy density under high electric field compared to those of BT NF. The maximum discharged energy density in the nanocomposite with 2.5 vol% BT@Al2O3 NF is 7.1 J/cm3 at 3800 kV/cm with an efficiency of above 65.1%. According to the results of complex impedance analysis, coating Al2O3 layers on the surface of BT NF reduces the Maxwell-Wagner-Sillars interfacial polarization, which might be the reason of the improvement of the discharged energy density and discharged efficiency. This work may provide an effective solution to enhance discharged energy density in polymer-based nanocomposites.