Ultrafast Discharge and High-Energy-Density of Polymer Nanocomposites Achieved via Optimizing the Structure Design of Barium Titanates

Electrostatic capacitors have been applied into high-power-density pulsed power systems comprising moderate energy density and ultrafast charging/discharging in the order of magnitude with a few milliseconds. In this article, different BaTiO 3 nanostructures (e.g., nanoparticles, nanofibers, nanotubes, core–shell structure nanofibers) were synthesized and used to prepare polymer composite films in the poly(vinylidene fluoride) (PVDF) matrix. The effects of BaTiO 3 nanostructures on the dielectric constant, dielectric loss, alternating current conductivity, breakdown strength, energy density, and mechanical properties of nanocomposites were investigated systematically. The largest dielectric constant of 17.14 was found in the 4 vol % BaTiO 3 nanotube/PVDF nanocomposites. The BaTiO 3 @Al 2 O 3 nanofiber/PVDF nanocomposites show the highest energy density of 12.37 J cm –3 at 450 MV m –1, ultrafast discharge speed (0.32 μs), and good mechanical properties. This article could open up a convenient and effective way for practical application of power pulsed capacitors by tuning the filler nanostructure into polymer nanocomposites.