Preparation And Properties Of Two-dimensional Barium Titanate/polyvinylidene Fluoride Composite Dielectric

In the context of promoting the development of new energy,the research of dielectric materials is closely related to the integration of power storage and conversion equipment.The rapid development of energy storage technology can no longer be satisfied by materials with single performance,and the composite of two or more materials has become one of the hot spots in the field of energy storage research.Ceramic/polymer composite dielectric has the advantages of both ceramic materials and polymer matrix,with high dielectric constant,high dielectric strength,which has an important application prospect in the field of energy storage.In this paper,the two-dimensional barium titanate filler was first prepared by the molten salt method,and then polyvinylidene fluoride(PVDF)was used as the matrix.The composite dielectric with barium titanate volume fraction of 0.5%?1%?3%?5%?7%and 10%were prepared by solution casting method.The influence of barium titanate content on the dielectric properties and energy storage properties of the composite dielectric was studied by testing.Establish a composite dielectric simulation model,and use the multiphysics coupling simulation software COMSOL Multiphysics to calculate the electric field distribution of different forms of barium titanate,random orientation and horizontal regular orientation of barium titanate in the matrix,three-layer structure,etc.The influence of these factors on the electric field distribution in composite dielectric is analyzed.The test results show that the dielectric constant of the composite medium increases gradually with the increase of the volume fraction of barium titanate,and shows a decreasing trend with the increase of frequency;the tan?of the composite dielectric decreases first and then increases in the frequency range of 100-10~6Hz,as the frequency increases,the conductivity of the composite dielectric also increases,the greater the volume fraction of barium titanate,the greater the conductivity of the composite dielectric,but its breakdown field strength is getting smaller and smaller;In the 130k V/mm electric field,the maximum energy storage density of the composite dielectric with barium titanate volume fraction of 3%is 6.43J/cm~3.The simulation results show that,compared with zero-dimensional barium titanate filler,the electric field distribution in the composite dielectric is more uniform when the two-dimensional barium titanate is used as the filler,and the closer it is to the horizontal arrangement in the matrix,the smaller the distortion of the electric field.