Optimization And Improvement Of Barium Titanate Composite Materials And Research On Dielectric Energy Storage Performance

Dielectric materials are widely used in electronic components and power systems.More specifically,a capacitor having a high dielectric constant and an energy storage density(Ue)is very desirable to meet the demand for miniaturization of electronic devices and power systems.Both high dielectric constant and breakdown strength are prerequisites for high energy density.At the same time,the voltage breakdown strength(Eb)mainly guarantees the reliability of electronic and electrical components.The purpose of this study is to further improve the dielectric constant and breakdown strength of barium titanate polymer composites.The specific study is as follows:1.Barium titanate(BT)is attached to a cellulose structure and sintered at high temperature to form a three-dimensional structure of inorganic fillers.Polyvinylidene fluoride(PVDF)with high dielectric constant and high breakdown strength is added to the epoxy resin to form a polymer blended substrate.Finally,the composite material is cured in a vacuum.It is systematically studied between the influence of the volume fraction of fillers in 3D BT/PVDF-epoxy on the composites'structure and the final dielectric energy storage performance.The ultra-high dielectric constant and low dielectric loss composites were obtained at 31 vol%.dielectric constant is greater than290,low dielectric constant is less than 0.1(from 1 KHz to 1 MHz),and large energy storage densities have been achieved for PVDF-epoxy composites containing 3D BT networks.2.The good compatibility of barium titanate@graphene oxide nano dots/polyvinylidene difluoride composites film(BT@GOND/PVDF)is prepared by electrostatic adsorption.Graphene oxide nanodots improve the electrical properties of nanofillers by its quantum effects.Compared with the traditional PVDF/BT nanocomposites,the BT@GOND/PVDF nanocomposites show obvious advantages in overcoming the challenges of particles agglomeration,separation phase and preventing the breakdown strength decreased by minute quantity nanodots.A series of nanocomposites are prepared based on different loadings of BT@GOND and PVDF.Compared with the BT-PVDF,the dielectric constant,dielectric loss and electrical conductivity of BT@GOND/PVDF change in the desired direction.The maximum energy density of the nanocomposites with 3 wt%BT@GOND is 8.4 J/cm~3 which is about 1.83 times of pure PVDF and improved about 43%compared with same content BT nanocomposites.It is demonstrated that BT nanoparticles combined with GOND is potential route to prepare and improve dielectric energy nanocomposites.