Enhancing Energy Density of BaTiO3-Bi(M)O3@SiO2/PVDF Nanocomposites via Filler Component Modulation and Film Structure Design

The low energy density (Ud) of polymeric dielectrics is unfavorable for the integration and miniaturization of electronics, thus limiting their application prospects. Introducing high-εr(dielectric constant) ceramic nanofillers to polymer matrices is the most common strategy to enhance theirεr,and hence theirUd. By comparison, enhancing breakdown strength (Eb) is a more effective strategy to enhanceUd. Herein, 0.6BaTiO3-0.4Bi(Mg0.5Ti0.5)O3and 0.85BaTiO3-0.15Bi(Mg0.5Zr0.5)O3nanofibers coated with SiO2were utilized as fillers in PVDF-based nanocomposites. The combination of experimental and simulation results suggests that the intrinsic properties of nanofillers are the determining factor of theEbof polymer-based nanocomposites, and SiO2coating and film structure design are effective strategies to enhance theirEb, and consequently theirUd. As a result, the sandwich-structured PVDF/6 wt% 0.85BaTiO3-0.15Bi(Mg0.5Zr0.5)O3@SiO2nanofiber within PVDF/PVDF nanocomposite films achieved a maximumUdof 11.1 J/cm3at anEbof 458 MV/m, which are 2.15 and 1.40 times those of pristine PVDF, respectively.