Enhanced permittivity and energy density of P(VDF-HFP)-based capacitor using core-shell structured BaTiO3@TiO2 fillers

As the electronic industry developed rapidly, greater demands are required on the performance of dielectric composites, such as high permittivity, low dielectric loss, and high-energy density. Improving the compatibility of fillers in polymer matrix and uniform distribution of the electric field could increase the permittivity of such composites. Therefore, BaTiO 3 nanoparticles were coated by TiO 2 sol to fabricate BaTiO 3 @TiO 2 core-shell structured fillers in this paper. BaTiO 3 @TiO 2 fillers with gradient permittivity were firstly modified by dopamine in order to disperse in the composites homogeneously and adhere to poly(vinylidene fluoride- co -hexafluoropropylene) (P(VDF-HFP)) matrix tightly. At 1 kHz, the permittivity of the composite with 20 vol% BaTiO 3 @TiO 2 was 32.15, obviously larger than that of pure P(VDF-HFP) (6.92), and the dielectric loss was just 0.052. Consequently, the discharged energy density of the composite was enhanced to 0.23 J/cm 3 at 40 kV/mm, which was two times higher than that of pure P(VDF-HFP). This work provides a feasible approach to prepare high-performance dielectric composites.