LAUSR

Polymer dielectrics possess significant advantages in electrostatic energy storage applications such as high breakdown strength (Eb ) and efficiency (η), while their discharged energy density (Ud ) at high temperature is limited by the decrease in Eb and η. Several strategies including introducing inorganic components and crosslinking have been investigated to improve the Ud of polymer dielectrics, but new issues will be encountered, e.g., the sacrifice of flexibility, the degradation of the interfacial insulating property and the complex preparation process. Herein, we introduce three-dimensional rigid aromatic molecules into aromatic polyimides to form physical crosslinking networks through the electrostatic interaction between their oppositely charged phenyl groups. The dense physical crosslinking networks strengthen the polyimides to boost the Eb and the aromatic molecules trap the charge carriers to suppress the loss, allowing the strategy to combine the advantages of inorganic incorporation and crosslinking. We demonstrate that this strategy is well applicable in a number of representative aromatic polyimides and ultrahigh Ud of 8.02 J cm-3 (150 °C) and 5.12 J cm-3 (200 °C) is achieved. Furthermore, the all-organic composites exhibit stable performances during ultralong 105 charge-discharge cycles in harsh environments (500 MV m-1 and 200 °C) and prospects for large-scale preparation. This article is protected by copyright. All rights reserved.