Structure, dielectric, ferroelectric, and energy density properties of polyethersulfone-based composite for energy storage application

In recent years, the explore on the storage energy material of dielectric capacitor exhibits an explosive research boom. However, the smaller energy storage density and lower charge–discharge efficiency of primitive polymer dielectrics restrict the development of dielectric capacitors. Various methods have been proposed to achieve an excellent-overall performance of composite dielectric with good flexibility, great insulation strength, high energy storage density and energy storage efficiency. In this article, the polyethersulfone (PESU) composite material containing copper calcium titanate (CCTO) is prepared by the casting method. The linear dielectric of PESU was selected in this work as the matrix of composite dielectric, thus the dielectric properties of composite can be optimized, for example the dielectric strength of dielectric composite can be improved and dielectric loss can be reduced. Moreover, the polarization of it is also supposed to explore, and the relationship and mechanism between the micro-structure and the macro-performance of composite via the introduction of with different contents of inorganic fillers (wt%) also can be completely studied. Finally, an appropriate doping ratio of inorganic fillers in the polymer-based composite dielectric with excellent breakdown strength and energy storage performance was successfully obtained. Interestingly, the discharge energy density of the 2 wt% CCTO/PESU dielectric composite reaches 13.5 J/cm³ under 500 kV/mm, and the charge–discharge efficiency of it is up to 78%. This work opens up a new direction for the product research and development of energy storage materials in field of dielectric capacitors with great energy storage density, high efficiency and excellent breakdown strength.