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

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)).

Nonlinear dielectric thin films for high-power electric storage with energy density comparable with electrochemical supercapacitors.

Although batteries possess high energy storage density, their output power is limited by the slow movement of charge carriers, and thus capacitors are often required to deliver high power output. Dielectric capacitors have high power density with fast discharge rate, but their energy density is typically much lower than electrochemical supercapacitors. Increasing the energy density of dielectric materials is highly desired to extend their applications in many emerging power system applications.