Tuneable conductivity at extreme electric fields in ZnO tetrapod-silicone composites for high-voltage power cable insulation

Abstract

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.

Nucleation of electro‐active β and γ‐phases in P(VDF−HFP) for manufacturing energy harvesting device and self powered weight measuring device

“…After the salt filler CuCl 2 , 2H 2 O is introduced in prominent peaks at 1234 (δ[CH 2 ] + o[CH 2 ]) and 1274 cm −1 ( ν s [CF 2 ]– ν s [CC] + δ [CCC])appeared in the doped sample which represents that γ and β‐phases appeared in the doped sample respectively (Figure 3(A)) [ 2,37 ] . Apart from this, the existence of both the β and γ‐phases are indicated by the peaks at 841 ( r [CH 2 ]– ν s [CF 2 ]) and 509 cm −1 also (Figure 3(A)) [ 2,37–42 ] . From the Figure 3(A) it is seen that almost all the α‐phases disappeared due to doping of the Cu‐salt fillers and doping has transformed crystallographic phases.…”

“…In our present work, P(VDFÀHFP) is taken to be the host polymer. There are several methods like stretching, poling, and adding nano-particles to improve piezoelectricity in P(VDFÀHFP) [38][39][40] . CuCl 2 , 2H 2 O are added to this polymer to induce electro-active phases that increase piezoelectric performance of the material without any poling or stretching.…”

Ternary Siloxane Copolymers Based Tough Elastomer under Ultralow Temperatures Condition

“…With the continuous exploration of the Earth and extraterrestrial space, human beings are exposed to increasingly extreme environments, among which ultralow temperature conditions are one of the main challenges. − Silicone elastomers, characterized by exceptional resistance to high and low temperatures, − radiation, , and ultraviolet light, , as well as insulation, − air permeability, , and physiological inertness − properties, find widespread application in various fields, including electronic/electrical, aerospace, petrochemical, construction, transportation, and daily chemical industries. Notably, ethyl silicone rubber has attracted increasing attention as the elastomer material with the lowest known glass transition temperature. , Derived from the cross-linking of linear polydiethylsiloxane (PDES), with −Si–O–Si– as the main chain and –CH 2 CH 3 as the side group, ethyl silicone rubber exhibits a glass transition temperature of −145 °C.…”

Gas-Sensing Properties and Mechanisms of 3D Networks Composed of ZnO Tetrapod Micro-Nano Structures at Room Temperature

“…Fortunately, due to its unique structure and exceptional performance, ZnO-T has garnered significant interest from users and scientists alike. It is widely utilized in various fields such as insulation materials [ 33 ], medical treatments [ 34 ], photocatalysis [ 35 ], photoluminescence [ 36 ], and gas detection [ 37 ]. In fact, it can be considered the most important structure from an application perspective [ 38 ].…”