Self-Healing in Dielectric Capacitors: a Universal Method to Computationally Rate Newly Introduced Energy Storage Designs

Abstract

Metal-film dielectric capacitors provide lump portions of energy on demand. While the capacities of various capacitor designs are comparable in magnitude, their stabilities make a difference. Dielectric breakdowns - micro-discharges - routinely occur in capacitors due to the inevitable presence of localized structure defects. The application of polymeric dielectric materials featuring flexible structures helps obtain more uniform insulating layers. At the modern technological level, it is impossible to completely avoid micro-discharges upon device exploitation. Every micro-discharge results in the formation of a soot channel, which is empirically known to exhibit semiconductor behavior. Because of its capability to conduct electricity, the emerged soot channels harm the subsequent capacitor performance and decrease the amount of stored energy. The accumulation of the soot throughout a dielectric capacitor ultimately results in irreversible overall failure. In the context of the dielectric breakdown, self-healing designates a range of chemical processes, which spontaneously rearrange the atoms in the soot channels to partially return their insulative function. We developed a universal method capable of rating new capacitor designs including electrode and polymer material and their proportions. We found the best-performing designs produce abundant volatile by-products after micro-discharge, whereas the soot samples exhibit lower electronic conductivities. We proved the capability of the theoretical method to rate the empirical performance of the known capacitors. The method relies on various electronic-structure simulations and potential landscape explorations. The reported advance opens an impressive avenue to computationally probe thousands of hypothetical capacitor designs.