Enhancing high-temperature capacitive performance of polyetherimide composites through hydrogen bonding

High-temperature and electric field stability are critical for the long-term performance of advanced dielectric materials. Polymer-based dielectric materials possess benefits such as high energy density, charge-discharge efficiency, and environmentally friendly processing, but they tend to suffer from increased energy loss and reduced breakdown strength at elevated temperatures. This article presents a series of composite films made from polyetherimide (PEI) and poly (ether naphthylamide) (PEENA) in varying compositions, designed to mitigate beta-relaxation through intermolecular hydrogen bonds. These hydrogen bonds significantly improve breakdown field strength and lower leakage current at elevated temperatures. Notably, the 30 wt% PEENA/PEI composite maintained a dielectric loss below 0.01 from room temperature to 200 degrees C, demonstrated a breakdown field strength of 596 MV m-1 at 150 degrees C, along with a discharge energy density of 4.78 J cm-3 under electric field strengths of 500 MV m- 1, with a charge-discharge efficiency surpassing 90 %. These results highlight the significant impact of hydrogen bonding on improving the dielectric characteristics of polymer composites, making them potentially useful in high-temperature environments.