High‐Temperature Dielectric Polymer Composites for Energy Storage Capacitors

ABSTRACT Dielectric energy storage capacitors are essential components in modern electronic and power systems, enabled by rapid charging and discharging and intrinsically high power density. The deployment of smart power transmission, photovoltaic power conversion modules, pulsed power electronics, new energy and hybrid vehicles, and advanced defense systems is intensifying the demand for reliable energy storage under high temperature and high electric field conditions. Relative to batteries and supercapacitors, dielectric capacitors offer distinct advantages in operating voltage, power density, and safety, and are therefore central to emerging ultrahigh power platforms. This review consolidates recent representative advances in high temperature dielectric polymer composites for energy storage. We first summarize the fundamental mechanisms governing energy storage and polarization in dielectrics, and then analyze the dominant conduction and loss processes that limit performance at elevated temperatures. Next, we categorize high temperature energy storage materials, including all organic dielectrics, nonpolar ceramics, organic inorganic composites, and polymers engineered through molecular structure design. Finally, we identify urgent scientific and technological bottlenecks and outline prospective research directions toward practical high temperature capacitive energy storage.