(420e) Dielectric Polymers Under Elevated Temperatures and High Electric Fields

With unique features including excellent electrical insulating properties, lightweight, mechanical flexibility and scalability, dielectric polymers are universally used for insulation on wires and cables and also enable the development of high-energy-density capacitors for electrical energy storage. However, with exponential increase of electrical conduction under elevated temperatures and high applied electric fields, dielectric polymers are limited to relatively low working temperatures, and thus fail to meet the rising demand for electricity under the extreme conditions present in applications such as advanced microelectronics, electric vehicles and aerospace power electronics. This talk will describe our most recent results on the dielectric polymers and nanocomposites designed for high-temperature applications. Specifically, the introduction of inorganic wide bandgap nanofillers into the polymers yields significantly reduced high-field conduction, and consequently, great improvements in the charge-discharged efficiency and discharged energy density at high temperatures. The origins of the marked improvement in the high-temperature capacitive performance of the crosslinked polymers are traced to efficient charge-trapping by a range of the molecular trapping centers resulting from the crosslinked structures. This talk will discuss fundamental insights into the tradeoff between dielectric constant and high-field energy loss in dielectrics and the mechanisms that control electrical conduction in polymers at high temperatures under the applied fields, which is relevant to a variety of flexible organic energy materials and devices.