Concurrently enhanced dielectric properties and energy density in poly(vinylidene fluoride)-based core–shell BaTiO3 nanocomposites via constructing a polar and rigid polymer interfacial layer

Abstract

The interfacial zone plays a key role in regulating the dielectric capabilities of polymer-based composites. In this article, two kinds of polar polymers were designed and selected as the shell layer of BaTiO₃ nanoparticles to investigate the influence of the chain conformation and band-gap width of an interfacial modifier on the dielectric behavior and energy storage properties of ferroelectric poly(vinylidene fluoride) (PVDF)-based nanocomposites. Compared with the polar coil-chain cyano-polymer poly[bis(2-cyanoethyl)-2-vinylterephthalate] (PECN), the polar rigid-chain cyano-polymer poly[bis(4-cyanophenyl)-2-vinylterephthalate] (PBCN) modifier with a high dielectric constant (ε_r) and low band-gap width showed a more noticeable effect on the enhanced dielectric and energy density storage of PVDF-based nanocomposites. The ε_r of PBCN@BT/PVDF nanocomposites increased from 7.8 to 16.9 at 10³ Hz with the increasing PBCN@BT content from 0 vol% to 9 vol%. In addition, the highest breakdown strength of 464 MV m⁻¹ and the maximum discharge energy density of 10.86 J cm⁻³ were achieved in 1 vol%-PBCN@BT/PVDF nanocomposites due to the higher electron affinity. This work furnishes a potential pathway for reaching the high-energy-density of polymer-based nanocomposites by taking the rigid polymer modifier with a low band-gap width.