Deep Well Trapping of Hot Carriers in a Hexagonal Boron Nitride Coating of Polymer Dielectrics

Abstract

Polymer dielectrics can be cost-effective alternatives to conventional inorganic dielectric materials, but their practical application is critically hindered by their breakdown under high electric fields driven by excited hot charge carriers. Using a joint experiment–simulation approach, we show that a 2D nanocoating of hexagonal boron nitride (hBN) mitigates the damage done by hot carriers, thereby increasing the breakdown strength. Surface potential decay and dielectric breakdown measurements of hBN-coated Kapton show the carrier-trapping effect in the hBN nanocoating, which leads to an increased breakdown strength. Nonadiabatic quantum molecular dynamics simulations demonstrate that hBN layers at the polymer–electrode interfaces can trap hot carriers, elucidating the observed increase in the breakdown field. The trapping of hot carriers is due to a deep potential well formed in the hBN layers at the polymer–electrode interface. Searching for materials with similar deep well potential profiles could lead to a computationally efficient way to design good polymer coatings that can mitigate breakdown.

Enhanced Anticarbonization and Electrical Performance of Epoxy Resin via Densified Spherical Boron Nitride Networks

“…Hexagonal boron nitride (hBN) is one of the inorganic insulating materials with high thermal conductivity, , flame stability, and a relatively low dielectric constant similar to that of epoxy resin. , Du et al improved the tracking failure performance of epoxy resin by enhancing its thermal conductivity through the addition of hBN . Yin et al prepared epoxy matrix nanocomposites with flakes of dopamine-modified hBN and rigid α-Al 2 O 3 microspheres, which have carbonization resistance on the insulating surface .…”

“…Yang et al fabricated epoxy/hBN composites with nacre-inspired structures through 3D printing, while the BN shell structure acts as a barrier to prevent the flame from entering during the flame exposure . Linker et al verified that hBN mitigates the damage caused by hot carriers, thus increasing the breakdown strength . For this reason, it appears to be an ideal choice to present epoxy resin with anticarbonization and fast heat dissipation properties.…”

“…4 Linker et al verified that hBN mitigates the damage caused by hot carriers, thus increasing the breakdown strength. 12 For this reason, it appears to be an ideal choice to present epoxy resin with anticarbonization and fast heat dissipation properties.…”

Enhancing corona resistance in Kapton with self-assembled two-dimensional montmorillonite nanocoatings

“…12 Among all the polymer modification methods, micro-and nano-polymeric composites containing inorganic fillers have attracted extensive and increasing research interest due to their potential enhancement in terms of electrical discharge resistance, treeing resistance, and dielectric strength. [13][14][15][16][17] Montmorillonite (MMT), an important member of the natural inorganic 2 : 1 smectite clay family, consists of a nanodimensional layered structure that is similar to those of mica and talc. It can be fully exfoliated into single-layer nanosheets with a very high aspect ratio for the formation of highly structured nanocomposites.…”

Dynamics of an impurity ion transport in oil‐paper insulation under various electric fields

“…In addition, to simulate the ionic mobility under AC electric fields, an electric field strength of 0.074 V/Å was used [45]. It should be noted that although first-principle molecular dynamics is more accurate, which considers polarisation, higher electric fields ranging from 0.01 to 0.09 V/Å were also used to simulate charge transport in polyethylene or nanocomposites [46][47][48]. Furthermore, in recent simulations of the ageing process of alkanes, the highest electric field used in the simulation reached up to 0.2 V/Å, still significantly higher than the experimental value [49].…”