High-Temperature Dielectric Energy Storage Performance of MgO/PEI Nanocomposites

High temperature polymer dielectrics, which are expected to perform well under harsh conditions such as high field strength and high temperature, have attracted increasing interest in recent years. Among these, polyetherimide (PEI) dielectric films have attracted attention due to their reliable temperature resistance and excellent dielectric performance, making it a promising candidate for application in high-temperature capacitor films. Nevertheless, to further improve its capacitive performance, a simple yet effective inorganic doping modification has been proposed in this study. By filling PEI with small amounts of MgO nanoparticles, the energy storage performance of the nanocomposite is improved. The results show that the inorganic MgO fillers are uniformly dispersed in the PEI matrix, and the dielectric constant and energy storage density of the nanocomposites are improved even at a low filler content of 1 vol%. An effective method for further improving the dielectric energy storage in polymer capacitor films has been developed in this study.