All-organic Energy Storage Dielectrics with Synergistic Optimization of Polarization and Breakdown Characteristics

Polymer dielectric is an important component of electrostatic capacitors, and the studies of polymer dielectrics with excellent energy storage characteristics are of great significance to the development of electrostatic capacitors. Polyvinylidene fluoride (PVDF) has attracted widespread attention because of its high dielectric constant. However, PVDF's poor insulation properties put serious constraints on its excellent energy storage density. In this research, a double-layer energy storage dielectric was prepared by introducing polyetherimide (PEl) with excellent insulation characteristics, using PVDF to provide a high polarization strength, and employing PEl to inhibit the growth of the conductive path. Through such preparations, the composite dielectric (PVDF/PEI) was endowed with both excellent polarization and high voltage resistance characteristics and obtained an all-organic composite dielectric with outstanding energy storage characteristics. The obtained PVDF/PEI composite dielectric can withstand an electric field strength of 500 MV/m, which is 2 times that of PVDF and provides an energy storage density that is 1.89 times that of PVDF. In summary, the energy storage density of PVDF has been significantly increased by the introduction of PEI.