Polymer dielectrics for capacitive energy storage: From theories, materials to industrial capacitors

The evolutionary success in advanced electronics and electrical systems has been sustained by the rapid development of energy storage technologies. Among various energy storage techniques, polymeric dielectric capacitors are gaining attention for their advantages such as high power density, fast discharge speed, cost-effectiveness, ease of processability, capability of self-healing, and tailorable functional properties. Great advances have been made in this field over the past decade, involving the discovery of new dielectric polymers, innovation of basic processing technologies, as well as the extension toward up-and-coming material computations and design strategies. This review provides a comprehensive understanding of polymeric dielectric capacitors, from the fundamental theories at the dielectric material level to the latest developments for constructing prototypical capacitors, with an emphasis on synergetic strategies for enhancing dielectric and energy storage properties. To begin with a brief introduction and description of the fundamentals, the subsequent sections cover intrinsic polymers, blended polymers, polymer nanocomposites, multilayer polymers, metacapacitors, and their properties. Then, we discuss corresponding fabrication techniques and highlight the challenges of commercialization, from polymer dielectric materials to film capacitors in developing commercial prototypes. Finally, we comment on the current state and future requirements for the development of polymer dielectric capacitors to high-performance devices.