Core-satellite ultra-small hybrid Ni@BT nanoparticles: A new route to enhanced energy storage capability of PVDF based nanocomposites

Polymer-based composites comprising of high dielectric constant ceramic nanoparticles are widely used in dielectric capacitors due to their excellent energy storage and processing properties. In this study, ultra-small Ni nanoparticles were used to fabricate core-satellite structured hybrid Ni@BT nanoparticles. Compared with BT/PVDF composites, the Ni@BT/PVDF nanocomposites exhibited the enhanced energy storage properties due to the low electric conductivity, small dielectric loss and improved breakdown strength. The maximum discharged energy density reached 9.55 J/cm 3 for nanocomposites with 3 vol% Ni@BT at the electric field of 350 kV/mm, which was nearly eight times of commercial BOPP (1.2 J/cm 3 at 640 kV/mm) and was around 208% compared to the pristine PVDF (4.58 J/cm 3 at 340 kV/mm). The improved energy density of the nanocomposites could be attributed to the Coulomb-blockade effect of the introduced ultra-small Ni nanoparticles exactly. This work provides an effective approach to improve the energy storage property of dielectric nanocomposites.