8 - Electrospinning Functional Fillers/Polymer Composites With High Energy Storage

Abstract

There is a rapid need for a kind of capacitor with smaller size, higher performance, and better processability, which requires the corresponding dielectric materials with high energy storage density. Conventional dielectric materials include inorganic ceramic materials and polymer materials. Common inorganic ceramic materials such as barium titanate (BaTiO3), calcium copper titanium oxide (CCTO), etc. have very high dielectric permittivity, but their preparation process is complex, and the dielectric breakdown strength is low. Common polymer materials like polyethylene, polypropylene, polytrifluoroethylene, and epoxy resin are flexible, low dielectric loss, easy to process, but their dielectric permittivity and thermal conductivity is relatively low. A single dielectric material has been difficult to meet the needs of industrialization. Due to good processability and compatibility with the electronic circuit integrated system of the polymer materials, the majority of high dielectric composite materials tend to choose polymer-based nanocomposites. People can choose different types of fillers and polymer composites to be satisfied with the dielectric properties and meet the needs of industrial processing, which makes the polymer-based composite energy storage materials of wide concern. Fillers are a key factor restricting the performance of polymer matrix composites. The common high dielectric permittivity fillers are BaTiO3, CCTO, etc. The traditional nanoparticles require a high content of composites, but that will lead to lower processing performance. The inorganic ceramic nanofibers with a high aspect ratio have a lower percolation threshold and lower surface energy than nanoparticles, which makes nanofibers reach the percolation threshold easily and prevent agglomeration in matrix. Electrospinning technology is a simple and convenient way to prepare nanofibers whose morphology and microstructure can be controlled. In particular, various composite fibers can be prepared by adding the components directly into the electrospinning solution, which overcomes the shortcomings of traditional synthesis methods. The purpose of this chapter is to introduce the application of electrospinning technology in the preparation of multifunctional fillers and polymer composites with high energy storage density in recent years. After a brief introduction of electrospinning technology, this chapter will focus on the single structure of inorganic fillers and heterostructured nanofibers prepared by electrospinning, as well as the dielectric properties of the nanocomposites using the electrospun fillers and polymer fibers.