Fluorinated Polyimides incorporated with heterogeneous ZrO₂@KNbO₃ as multiple carrier transport barriers for Ultra-High energy storage

Advanced electronic devices and electrical power systems require high capacitor energy storage, fast charge–discharge speed and high temperature stability. Inorganic and organic nanocomposite film can achieve this great goal, but the major obstacle is the easy failure of breakdown in harsh environments. Here, we report a seires of inorganic–organic composite films prepared by blending a novel core–shell heterogeneous ZrO₂@KNbO₃ with fluorinated polyimide (FPI). The ZrO₂@KNbO₃ forms a distinctive sandwich-like microstructure, which delivers the p-n-p heterojunction interfaces. Multiple energy barriers, arisen at the interfaces, block the charge carrier transport. As a result, the 0.3 ZrO₂@KN/FPI nanocomposite film achieves ultrahigh energy densities of 11.62 J cm⁻³ and 7.9 J cm⁻³ under electric fields of 665.6 MV m⁻¹ and 550 MV m⁻¹ at 25°C and 150°C, respectively, giving rise to a concurrent enhancement in breakdown strength and electrical displacement. Additionally, the 0.3 ZrO₂@KN/FPI composite film exhibits superior charge–discharge cycling stability, enduring up to 100,000 cycles. This research provides a cutting-edge perspective to regulate the charge transport path, especially to inhibit charge transport at the interfaces, demonstrating a great potential for high-temperature dielectric capacitor applications.