Largely enhanced dielectric properties of polymer composites with HfO2 nanoparticles for high-temperature film capacitors

Polymer dielectrics are preferred materials for high-energy-density capacitive energy storage. In particular, hightemperature dielectrics that can withstand harsh conditions, e.g., >= 150 degrees C, is of crucial importance for advanced electronics and electrical power systems. Herein, high-temperature dielectric polymer composites composed of polyetherimide (PEI) matrix and hafnium oxide (HfO2) nanoparticles are presented. It is found that the incorporation of HfO2 with a moderate dielectric constant and a wide bandgap improves the dielectric constant and simultaneously reduces the high-field leakage current density of the PEI nanocomposites. As a result, the PEI/HfO2 composites exhibit superior energy storage performance to the current high-temperature engineering polymers at elevated temperatures. Specifically, the nanocomposite with 3 vol% HfO2 displays a discharged energy density of 2.82 J/cm(3) at 150 degrees C, which is 77% higher than neat PEI. This work demonstrates the effectiveness of incorporation of the nanofiller with a medium dielectric constant into the polymer on the improvement of high-temperature capacitive properties of the polymer composites.

Automated summary

Polymer dielectrics, particularly high-temperature polymer composites with hafnium oxide nanoparticles, show improved dielectric properties and energy storage performance at elevated temperatures. The incorporation of HfO2 enhances the dielectric constant and reduces leakage current density, leading to superior energy storage compared to conventional engineering polymers. This study demonstrates the effectiveness of incorporating nanoparticles with a medium dielectric constant in improving the high-temperature capacitive properties of polymer composites.