Charge-trap engineering in polymer dielectric capacitors
Charge-trap engineering in polymer dielectric capacitors lead image
Electronics, audio equipment, industrial and medical equipment, and renewable energy systems are a few applications that depend on polymer dielectric capacitors. Although highly reliable and easy to process, the low operating temperature of the capacitors limits their effectiveness in harsh conditions exceeding 140 C, such as those encountered by electric vehicles, aerospace power electronics, and underground energy source exploration.
Increasing a polymer’s glass transition temperature, Tg, can improve its thermal and mechanical stability at elevated temperatures, but even polymers with high Tg exhibit high leakage currents when exposed to increased temperature and electric field conditions. Chen et al. investigated the use of engineered nanoscale interfaces in all-polymer, high-Tg composites to suppress charge leakage while maintaining effective processability and scalability.
“Our work involved blending two special heat-resistant plastics, polyetherimide and polyimide, in a way that creates tiny, sell-distributed ‘islands’ of one material inside the other,” said author Qiyan Zhang. “These islands act as traps for electric charges, preventing leakage and allowing more reliable energy storage even under extreme conditions.”
The innovative all-polymer capacitor design reduced leakage current over ten times versus pure polyetherimide, while demonstrating simpler processing compared to conventional filler-modified or multilayer-structured polymer films. This simple, scalable blending process led to an increase in breakdown strength, energy density, and efficiency at 150 C.
“By eliminating the need for inorganic fillers or complex multilayers, our all-polymer approach could accelerate the adoption of high-performance dielectric films in real-world applications,” said Zhang.
The research team plans to explore other high-Tg polymer pairs and stimuli-responsive polymers with self-healing properties and hopes to scale up industrial capacitor fabrication to accelerate real-world adoption.
Source: “Enhancement of high-temperature capacitive energy storage performance in all-polymer dielectric composites via microphase separation,” by Jinbao Chen, Ting Li, Yongbiao Zhai, Wugang Liao, and Qiyan Zhang, Applied Physics Letters (2025). This article can be accessed at https://doi.org/10.1063/5.0280505 .
