Outstanding discharge energy density and efficiency of the bilayer nanocomposite films with BaTiO3-dispersed PVDF polymer and polyetherimide layer

Abstract

Dielectric polymer nanocomposite films have been widely studied because of their high polarization and electric breakdown strength, leading to high discharge energy density (Ud). However, nanocomposites with high Ud often show low discharge energy efficiency (η). In order to achieve both high Ud and η simultaneously, a series of novel bilayer polymer nanocomposite films composed of pure polyetherimide (PEI) layer and BaTiO3-dispersed poly(1,1-difluoroethylene) (BT/PVDF) layer were prepared by hot-pressing method in this work. The bilayer composites exhibit high η > 84% at 600 MV⋅m−1, which are much larger than most reported values (η < 70%). Specially, the highest η of 84.48% and Ud of 8 J·cm−3 at 600 MV·m−1 were obtained for the bilayer films composed of PEI and 3 vol% BT/PVDF layers, which is promising for pulsed power applications.