Electric Field Grading Material Based on Thermally Reduced Graphene Oxide

Abstract

Silicone rubber filled with low amounts of thermallyreduced graphene oxide exhibit non-linear conductivitywith exposed to increased electric fields. Such materialcan be interesting as electric field grading material inHVDC cable accessories. In this study graphene oxidewas thermally reduced (rGO) at 120 and 180 °C during12 hours in a hot air oven. The reduction was confirmedby TGA and FTIR. 3 wt.% rGO was then dispersed in asilicone rubber matrix and homogenous dispersion wasdemonstrated by the scanning electron microscopy. TherGO-filled silicone rubber (120 and 180 °C reduced)exhibited a non-linear resistivity when exposed to anincreasing electric (DC) field. The conductivitydecreased from 10^14 to 10^11 Ohm m when the electricfield increasing from 0.2 to 6 kV/mm. The onset of thenon-linear conduction occurred in the range of 1 – 2kV/mm. The long-term stability of the conductivity ofthe silicone rubber composite was tested. After 47 daysageing at 120 °C, therGO/silicone rubber compositeexhibited a slight increase in the onset of non-linearconduction, as well as a minor increase in resistivity.