Novel dielectric films with high energy density

Abstract

Capacitive energy storage devices are essential components in modern electronics for power conditioning, conversion and renewable integration. The state-of-the-art bi-axially oriented polypropylene dielectric film has a breakdown strength of >730 MV/m and low dielectric loss of <;0.0002 at 1kHz, but suffers a low dielectric constant of 2.2. Rational development of high permittivity polymers is undertaken with the guidance of a high throughput, first principles computation-based polymer design space search engine, parallelized with chemical synthesis and high field electrical characterizations. Further understanding of the correlation between materials' molecular and microscopic structures and electrical characteristics under high fields is essential to the rational design of new dielectric materials. In this paper, the electrical characteristics of a newly synthesized thiourea-etheramine copolymer with a dielectric constant of 5.5 were systematically investigated by a combination of broadband dielectric spectroscope, modified Sawyer-Tower polarization loop tester and pre-breakdown conduction measurements, to provide critical feedback for the rational design of polymers with high dielectric constant and low loss.