High Energy Storage of Polymer Blend at Elevated Temperature

The capacitive energy storage of polymer dielectrics degrades significantly at high temperatures mainly due to dramatically enhanced conduction. To enable enhanced dielectric energy storage at elevated temperature, a blend strategy is developed here using polyimide/ polycarbonate (PI-PC) with various PI content. The energy storage behavior of polymer blend can be effectively tuned by changing PI concentration. The optimized blend with a composition of 0.90PI-0.10 PC exhibits a large breakdown strength of 709.4 MV m⁻¹ and a high discharged energy storage density of 7.9 J cm⁻³ at 150 °C. Meanwhile, the blend shows a discharged energy density of 0.72 J cm⁻³ with a high charge-discharge efficiency at 150 °C and 200 MV m⁻¹, exceeding a benchmark biaxially oriented polypropylene under the same condition. This work provides a scalable approach for developing dielectric materials for energy storage applications.