Simulation of the Energy Storage Properties of Polyetherimide Nanodielectrics at High Temperatures

Linear polymer dielectrics have become the ideal materials for high-energy-density capacitors because of their high breakdown strength and lightweight, but the low-energy storage density greatly limits their practical application. The charge injection and transport are closely related to the energy storage performance. In order to clarify the key factors affecting the energy storage performance of the linear polymer dielectrics, we constructed an energy storage and energy release model of the nanocomposite dielectrics, and simulate the energy storage performance of the polyetherimide nanocomposite (PEI PNCs) dielectrics with different hopping distances and hopping barriers at different temperatures and different electric fields. Applied a triangular voltage to the PEI PNCs, the electric displacement-electric field ( ${D}$ - ${E}$ ) loops are computed, and then, the energy storage densities and the energy efficiencies are obtained. The changing trends of the simulation results are consistent with those of experiments. The changes of charge hopping barrier and average hopping distance in PEI PNCs have an impact on the carrier mobility and current density, and then affect the discharged energy density and energy efficiency of dielectric capacitors. A higher hopping barrier and a smaller average hopping distance can improve the energy storage performance of the dielectrics, especially at high temperatures. This research can provide theoretical and model support for the insulation design and performance improvement of nanocomposite dielectrics.