Effect of shape of inorganic particles on dielectric properties of polymer composites with high energy density

Abstract

The formation of two-phase composite materials by adding inorganic ceramic particles in the organic matrix is a hot and difficult point in the current study of high energy storage density. The electrostatic energy storage characteristics of the material are determined by its internal electric field distribution. For pure polymer materials, the internal electric field is uniformly distributed in a uniform external electric field environment, but when the inorganic particles are filled to form a composite material, the local electric field of the material will be distorted, which will affect the dielectric properties of the composite material. In this paper, the electric response properties of particles with different shape, including sphere, fiber and disk and its special arrangement has been systematically studied. The results show that both the shape and the spatial arrangement of the particles in the polymer matrix affect the local distribution of electric field. For spherical particles, there will exist be field concentration up and below the particle. For fibers, the field caused by the terminal surface bound charge should not be neglected when the aspect ratio is not large enough. At last, three three-dimensional simulation models of composites with spherical, fiber and disk particles have been established. It is indicated that composites with fiber particle possess the highest effective permittivity, while the disk particle is the lowest under the same concentration. The investigation of this paper is of great significance to understand the microscopic mechanism of energy storage.