Materials & Design, 2018, vol 140pp. 114-122
Poly(vinylidene fluoride) (PVDF) based composites incorporating conductive fillers enable quick achievement of ultrahigh dielectric constant based on percolation theory; however, the accompanying drawbacks high dielectric loss and poor insulation have impeded their practical applications. A novel ternary Bi2S3-BaTiO3/PVDF nanocomposite architecture has been constructed via hot stretching process, where oriented Bi2S3 nanorods arranged as numerous microcapacitors with homogeneously distributed high-k BaTiO3 nanoparticles embedded in PVDF as dielectric media. The series connected numerous microcapacitors provide high dielectric constant which is testified by microcapacitor model simulation while the alignment of one-dimensional microcapacitors along stretching direction greatly reduces the dielectric loss caused by semiconductor Bi2S3. Numerical simulations reveal the positive effect brought by one-dimensional nanofiller orientation in breakdown strength enhancement. This study provide an alternate strategy to reach a balance between high dielectric permittivity, low dielectric loss and high breakdown strength in dielectric composites with conductive filler, which are promising for extensive applications in flexible electronic devices and electrostatic energy storage devices.