Recent advances in elevated-temperature flexible composite dielectrics for energy storage applications

Dielectric composites play a crucial role in meeting the growing demand for high-energy-density capacitors that can operate effectively in challenging environments. These applications include aerospace power management, underground oil and gas exploration, electrified transportation, and pulse power systems. This work provides a comprehensive overview of current research on flexible, high-temperature-resistant composite dielectrics for energy storage, emphasizing enhancing thermal stability and dielectric performance. Initially, this work examines the crucial characterization parameters that define the performance of dielectric energy storage materials at elevated temperatures and explores the mechanisms behind them. Subsequently, the recent research achievements and the primary challenges facing these flexible composite materials are summarized. Further discussions on strategies are performed for optimizing the microstructure of these materials to improve performance, where three key dimensions are analyzed, such as system selection, filler types, and structural design. Additionally, the review introduces innovative approaches to enhance the temperature resistance of flexible dielectric composites, employing machine learning algorithms and high entropy design concepts. Finally, a summary and future outlook on the potential development pathways in this field are concluded.