Chemical Compositions of Soot Samples in Gold Electrode Capacitors: Molecular Simulations

TL;DR

This study uses atomistic simulations to analyze soot composition in gold-electrode capacitors, revealing how different dielectrics influence soot properties and self-healing potential, with implications for extending capacitor lifespan.

Contribution

First atomistic simulation analysis of soot chemical composition in gold-electrode capacitors, linking soot properties to dielectric material and self-healing efficiency.

Findings

Gold atoms form clusters in soot, limiting interactions with non-metals.

Oxygen in polymers stabilizes gold via electrostatic attraction.

PP produces more gases and smaller soot particles than PI.

Abstract

Electrical breakdown in a dielectric capacitor occurs when the electric field strength across the dielectric material exceeds its breakdown strength. A conductive channel through the dielectric emerges, resulting in a sudden surge of current. Self-healing represents a phenomenon of restoration of a capacitor's performance. The efficiency of self-healing depends on the products of high-temperature decomposition of the electrode and dielectric. We report atomistic simulations of the soot's chemical composition in the case of gold electrodes and four popular dielectric polymers: polypropylene (PP), polyethylene terephthalate (PET), polycarbonate (PC), and polyimide (PI). We unravel that gold atoms form clusters within the carbon-rich soot, limiting their interactions with non-metal elements. The oxygen atoms of PET, PC, and PI act as stabilizers of gold thanks to electrostatic attraction. Compared to zinc, gold equalizes the soot conductivity in all samples but does not impact polymer gasification. The suitability of dielectrics for self-healing must be rated based on the volatile by-products: PP > PC > PET > PI. Mind that PP issues three times more gases than PI. Therefore, the size of semiconducting soot is substantially smaller in the case of PP than in the case of PI. The obtained numerical results provide unprecedented physical insights into the phenomenon of self-healing and clearly drive the efforts to extend the lifespans of the metalized film capacitors.