Engineering of core@double-shell Si@SiO2@PS particles towards improved dielectric performances: Filler domain-type polarization mechanism in PVDF composites

To concurrently improve both the dielectric constants (& epsilon;) and breakdown strength (Eb), and restrain the loss of original Si (silicon)/poly(vinylidene fluoride, PVDF), herein, we prepared the core@double-shell structured Si@SiO2(silica)@PS(polystyrene)/PVDF composites. The dielectric properties of composites were investigated in terms of various fillers and frequency, and polarization mechanism was examined by fitting the HavriliakNegami expression. The results verify that the polarization in Si/PVDF is governed by electron transport via multiple adjacent fillers, i.e., essentially a domain-type polarization. The core@shell particles affect the dielectric properties of composites by fundamentally changing the filler-cluster size. The Si@SiO2@PS/PVDF shows both high-& epsilon; and Eb owe to amplified filler-cluster size and significantly suppressed loss due to inhibited charge carrier migration synchronously. Both the core@double-shell filler design strategy and filler domain-type polarization mechanism provide helpful insights into the development of percolating composites with high & epsilon; and Eb but low loss for promising applications.