An In-Situ  Uv-Curable Polyacrylate Dielectric Material with High Energy Density for High-Temperature Capacitor

Abstract

Dielectric polymers typically have low discharge energy density and poor charge-discharge efficiency in high-temperature applications due to conduction losses and degraded breakdown strength. It makes necessary to include costly heat exchangers in high temperature applications such as electric vehicles and underground oil and gas exploration. Many scholars have paid attentions to the development of high-temperature energy storage capacitor films. In this study, an all-organic cross-linked polyacrylate (XL-PUA) dielectric film with a discharge energy density of 2.2 J/cm3 and a charge-discharge efficiency of 68% at 150 ℃ has been designed by in-situ UV polymerization. The conductive mechanism of cross-linked polymers under high temperature and electric field is also investigated. It is demonstrated that higher crosslinking density can deepen the charge trap depth and thus inhibit the high temperature conductivity of the polymer. The design of the two-component soft and hard segments allows the material to be fabricated into high-quality films of varying flexibility with uniform dielectric and capacitive properties. This is critical for its successful commercialization and practical application in high-temperature flexible circuits.

Keywords: dielectric film, polyacrylate, UV-cure, high-temperature capacitor, Energy storage