Tuneable conductivity at extreme electric fields in ZnO tetrapod-silicone composites for high-voltage power cable insulation
Journal article, 2022
Resistive Field Grading Materials (RFGM) are used in critical regions in the electrical insulation system of high-voltage direct-current cable systems. Here, we describe a novel type of RFGM, based on a percolated network of zinc oxide (ZnO) tetrapods in a rubber matrix. The electrical conductivity of the composite increases by a factor of 108 for electric fields > 1 kV mm-1, as a result of the highly anisotropic shape of the tetrapods and their significant bandgap (3.37 eV). We demonstrate that charge transport at fields < 1 kV mm-1 is dominated by thermally activated hopping of charge carriers across spatially, as well as energetically, localized states at the ZnO-polymer interface. At higher electric fields (> 1 kV mm-1) band transport in the semiconductive tetrapods triggers a large increase in conductivity. These geometrically enhanced ZnO semiconductors outperform standard additives such as SiC particles and ZnO micro varistors, providing a new class of additives to achieve variable conductivity in high-voltage cable system applications.
Author
Helena Greijer
Hitachi, Ltd.
Nicola Mirotta
Institute for organic syntheses and photoreactivity (ISOF-CNR)
E. Treossi
Institute for organic syntheses and photoreactivity (ISOF-CNR)
Filippo Valorosi
Institute for organic syntheses and photoreactivity (ISOF-CNR)
Fabian Schütt
University of Kiel
Leonard Siebert
University of Kiel
Yogendra Kumar Mishra
University of Southern Denmark
Rainer Adelung
University of Kiel
Vincenzo Palermo
Institute for organic syntheses and photoreactivity (ISOF-CNR)
Chalmers, Industrial and Materials Science, Materials and manufacture
Henrik Hillborg
Hitachi, Ltd.
Scientific Reports
2045-2322 (ISSN) 20452322 (eISSN)
Vol. 12 1 6035-Subject Categories
Materials Chemistry
Other Electrical Engineering, Electronic Engineering, Information Engineering
Condensed Matter Physics
DOI
10.1038/s41598-022-09966-4
PubMed
35410428