Porous Structure Induced Dielectric Loss Suppression for CB-g-PFOTES/PVDF Composites

Abstract

Polymer-based dielectrics have long been the focus of research in the field of flexible thin-film capacitors. However, the low energy storage density of polymer-based dielectrics has been an obstacle for practical applications, since the enhancement of the dielectric constant is often accompanied by an increase in the dielectric loss. In this study, a novel core–shell structured CB-g-PFOTES nanoparticles with porous carbon black (CB) as the core and 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (PFOTES) as the outer shell were successfully synthesized and further embedded into polyvinylidene fluoride (PVDF) matrix. As a result, the core–shell structured CB-g-PFOTES nanoparticles displayed notable improvements in the dielectric properties of composites. Typically, the CB-g-PFOTES/PVDF composites with a filler content of 2.5 wt% exhibited outstanding dielectric properties with a high dielectric constant of 33.2 and an extremely low dielectric loss of 0.0238 at 102 Hz. The significant suppression of dielectric loss was due to the fact that the porous structure of the CB effectively limits the interfacial charge transfer within the polymer matrix. This work provides a novel type of nanofiller for the fabrication of high dielectric nanocomposites, which is expected to further realize application in high energy storage density dielectric materials.