XLPE/h-BN Nanocomposites with Enhanced DC Insulation Properties

Nanocomposites have been developed as the third-generation insulating materials. This article introduces the crosslinked polyethylene (XLPE) nanocomposite dielectric doped with a small amount of nano-hexagonal boron nitride (h-BN), which exhibits excellent insulation properties under high dc voltage. The test results show that XLPE/h-BN nanocomposites possess significant improvements in dc breakdown strength and 0.1 wt% nano h-BN doping can actually increase the dc breakdown strength by 39%. The space charge properties of the XLPE/h-BN obtained by the pulsed electro-acoustic (PEA) measurements and the direct current integrated charge [DCIC-Q(t)] measurements show that the positive homocharge injection under dc voltage is obviously suppressed, and the electrical conductivity under relatively high electric field decreases. The thermally stimulated current results show that the nano h-BN doping introduces only deep charge traps (above 1 eV) to the XLPE matrix. The trap energy is deeper than that of the original traps, and this is the main factor leading to the improvement of the dc insulation properties. Besides, the doping of h-BN does not introduce impurities or change the crystallinity of XLPE. This article presents the novel XLPE/h-BN nanocomposites with excellent dc insulation properties and indicates the large potential of the nano h-BN-doped insulation materials.