Molecular-Scale Carrier Localization Boosts High-Temperature Energy Storage and High-Entropy Energy Harvesting.

Abstract

High-temperature insulation/energy storage applications boost the rapid development of polymer dielectrics such as polyimide (PI) with excellent thermal stability. However, PI exhibits significant leakage current due to intra- and inter-chain charge transfer complexes (CTCs), which seriously increases the risk of thermal runaway. Although single charge transfer inhibition strategies have been developed, the results remain unsatisfying due to the "short-board effect in carrier suppression." Herein, a "carrier localization" approach is introduced that synergistically regulates both intramolecular and intermolecular CT suppression. Thanks to molecular engineering and a directional intercalation structure, the all-organic polyimide dielectric materials with multidimensional carrier migration suppression achieve an exceptional breakdown strength of 878.9 kV mm^-1 and U_d of 8.93 J cm^-3 at 150 °C and energy density of 5.64 J cm^-3 at 200 °C (η > 90%), outperforming many reported systems. The all-organic polyimide dielectric materials also enable to possess high charge density (215 µC m^-2) when integrated into a self-excited triboelectric nanogenerator, which is highly desirable for the harvesting of low-frequency, irregular mechanical energy from a high-entropy environment. Collectively, this work provides a solid foundation for advanced energy storage and conversion applications.