Dielectric behaviors and high energy storage density of nanocomposites with core–shell BaTiO3@TiO2 in poly(vinylidene fluoride-hexafluoropropylene)

Abstract

Nanocomposites comprising a P(VDF-HFP) polymer matrix and core–shell structured nanoparticle fillers were prepared, in which a crystalline, ultrathin TiO₂ shell layer encapsulates BaTiO₃ nanoparticles. A large dielectric constant (>110) was obtained, which was unexpectedly more than 3 times higher than that of the nanocomposite without the TiO₂ shell layer. The significant improvement in electric polarization is attributed to the highly interactive interfaces among the multiple dielectric materials with the introduction of the intermediate TiO₂ layer, which also improves the breakdown field (>340 MV m⁻¹). Thus a resulting dielectric energy density of 12.2 J cm⁻³ is achieved, among the highest energy densities for polymer–ceramic composites.