High-Temperature Scalable Polymer Nanocomposites with Large Energy Density and High Charge-Discharge Efficiency Enabled Via Utilizing Al2o3 Nanofillers

Scalable polymer-based dielectric capacitors with excellent elevated-temperature capacitive performances are highly demanded in next-generation electronic power systems. Here, we design an effective and low-cost way to fabricate high-temperature polymer capacitors via adding Al2O3 nanoparticles (NPs) into polyetherimide (PEI) nanocomposites. Good thermal stability, high thermal conductivity of Al2O3 NPs and high glass transition temperature of PEI can cause the Joule heat, which is easy to generate under the condition of high temperature and large electric field, dissipate quickly, and therefore is conductive to the suppression of the dielectric loss and achievement of superior high-temperature capacitive properties. Consequently, even at 150 °C, the Al2O3 NPs/PEI nanocomposite delivers still slim electric displacement-electric field ( D - E ) loops, small remnant electric displacement ( D r ), and large maximum electric displacement ( D max ), thus resulting an ultra-high discharged energy density ( U e ) of 6.68 J cm -3 , which far exceeds the state-of-the-art polymer and polymer composites, and high efficiency ( η ) of 84.77% at 150 °C. This work addresses the paradox that large U e and high η can't be simultaneously achieved in high-temperature polymer composites and provides a good foundation for the mass production of polymer-based dielectric capacitors with outstanding high-temperature capacitive properties