Trap Engineering-Based Optimization via Polyetherimide with Molecular Semiconductor for Capacitive Energy Storage at High Temperatures

Polyetherimide (PEI)/molecular semiconductor-based all-organic dielectric composites have garnered significant attention due to their exceptional energy storage performance at elevated temperatures. In this work, the high-electron-affinity semiconductor 5,6,12,13-tetrachloro-2,9-bis(2-ethylhexyl)anthra[2,1,9-def:6,5,10-d′e′f]diisoquinoline-1,3,8,10(2H,9H)-tetraone (TCEHAQ) is employed as a filler to enhance the dielectric energy storage performance of PEI. It is believed that TCEHAQ can immobilize electrons and reduce charge transport in dielectric composites. The results demonstrate that the breakdown strength of PEI with only 0.5 wt% of TCEHAQ increased from 450 MV/m to 600 MV/m at room temperature, while the maximum discharge energy density (Ud) reached 5.99 J/cm3, and the discharge efficiency (η) was 96.5%. Meanwhile, the breakdown strength of the 0.5 wt% TCEHAQ/PEI blend at 150 °C was 500 MV/m, and the maximum Ud and η were 3.68 J/cm3 and 81.0%, respectively. This is a straightforward and effective method for fabricating large-area, high-quality dielectric energy storage films suitable for use in harsh environments.