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 (ε) 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 Havriliak-Negami 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-ɛ 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 ε and Eb but low loss for promising applications.