Interface modified Si@SiO₂/PVDF composite dielectrics with synchronously ameliorative dielectric and mechanical properties

To efficaciously decrease dielectric loss while still synchronously harvesting a high dielectric constant (e ') and breakdown strength (E-b), as well as good mechanical properties in silicon (Si)/poly(vinylidene fluoride) (PVDF), in this work, the core@shell structured Si@silicon dioxide (SiO2) particles were first prepared via a high temperature oxidation, and subsequently incorporated into the PVDF to generate morphology-dependent composites with a high-e ' and E-b but low loss. The SiO2 shell effects on the morphology, dielectric, and mechanical properties of PVDF composites were explored. In comparison to pristine Si/PVDF, the Si@SiO2/PVDF presents significantly suppressed loss and boosted E-b because the SiO2 interlayer not only efficiently blocks the connection between the raw Si and greatly impedes the long-range charges migration even at high filler loadings, but also obviously improves the compatibility between Si and PVDF at the interfaces which promotes fillers' uniform dispersion in host matrix, thus leading to enhanced dielectric and mechanical properties. The fitting result by the Havriliak-Negami equation theoretically elucidates the SiO2 interlayer's suppression effect on charge migration behavior in the composites. More importantly, dielectric properties can be efficiently turned via tailoring the SiO2 shell thickness. The Si@SiO2/PVDF with simultaneously enhanced dielectric and mechanical performances shows promising uses in the electrical and microelectronics industries.