Relaxor Ferroelectric Polymer–Poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) Terpolymer High Electric Energy Density and Field Dependent Dielectric Response

Abstract

Besides the high electrostriction in the relaxor P(VDF-TrFE-CFE) terpolymers, the high dielectric constant (> 50) and high breakdown field lead to a high electric energy density (∼10 J/cm3), which is attractive for the high efficiency charge storage capacitors. This paper presents charging and discharging behavior, as well as the discharged energy density as a function of the field. The field dependence of the polarization response and the polarization saturation at very high field result in a nearly linear increase of the discharged energy density with field. For the field dependent polarization response in the low to medium field range, Rayleigh's law has been introduced in the past to describe the field dependent behavior (with loss) in this field range. We examine the relationship between the Rayleigh's law and the complex dielectric constant notation used widely in the scientific and engineering community and show that a modified complex notation can describe the field dependent dielectric response with loss in the low and medium field range quite well. Keywords: Relaxor ferroelectricpolymercharging and dischargingdielectric response Acknowledgment The authors deeply appreciate many stimulating discussions with Prof. Newnham over many years. We appreciate greatly the financial support of the works reported here by ONR under Grant No. N00014-05-1-0455 and Grant No. N00014-05-1-0541 (MURI).