Highly Reliable Polymer Dielectric Materials for High‐Temperature Energy Storage Capacitors

ABSTRACT Film capacitors with superior high‐temperature energy storage and breakdown self‐healing properties are urgently demanded for advanced power systems. Currently, the excellent thermal stability of most polymer dielectrics depends on the aromatic conjugated backbone in the molecular structure. However, conjugation effects lead to a dramatic increase in conduction loss, deteriorating the high‐temperature energy storage performance. Meanwhile, aromatic dielectric materials form severe carbon deposition defects after electrical breakdown, losing their self‐healing ability. Here, the conduction loss mechanism that leads to the deterioration of the high‐temperature energy storage performance of polymer dielectrics is explored, and corresponding strategies to improve the energy storage performance are proposed. We further describe the breakdown self‐healing behavior and the gas‐condensation phase self‐healing features of polymer dielectrics, as well as strategies for designing polymer dielectrics with excellent high‐temperature energy storage and self‐healing ability. Finally, the future directions and opportunities for the development of highly reliable polymer dielectric materials for film capacitors are highlighted.