Nonlinear Conductivity and Space Charge Characteristics of SiC/Silicone Rubber Nanocomposites

Abstract

To achieve a preferable compatibility between liquid silicone rubber (LSR) and cable main insulation in a cable accessory, we developed SiC/LSR nanocomposites with a significantly higher conductivity nonlinearity than pure LSR, whilst representing a notable improvement in space charge characteristics. Space charge distributions in polarization/depolarization processes and surface potentials of SiC/LSR composites are analyzed to elucidate the percolation conductance and charge trapping mechanisms accounting for nonlinear conductivity and space charge suppression. It is verified that SiC/LSR composites with SiC content higher than 10 wt% represent an evident nonlinearity of electric conductivity as a function of the electric field strength. Space charge accumulations can be inhibited by filling SiC nanoparticles into LSR, as illustrated in both dielectric polarization and depolarization processes. Energy level and density of shallow traps increase significantly with SiC content, which accounts for expediting carrier hopping transport and surface charge decay. Finite-element multiphysics simulations demonstrate that nonlinear conductivity acquired by 20 wt% SiC/LSR nanocomposite could efficiently homogenize an electric field distributed in high-voltage direct current (HVDC) cable joints. Nonlinear conductivities and space charge characteristics of SiC/LSR composites discussed in this paper suggest a feasible modification strategy to improve insulation performances of direct current (DC) cable accessories.

Fascinating Electrical Transport Behavior of Topological Insulator Bi2Te3 Nanorods: Toward Electrically Responsive Smart Materials

“…As shown in Figure 3f, the Bi 2 Te 3 nanorods aggregates of nanorods can maintain the stable ON and OFF states to nearly constant ON/OFF resistance ratio of ≈10 3 at a reading voltage of 2.0 V. The response of the Bi 2 Te 3 nanorod aggregates for the electric field can maintain a stable response in the case of multiple switches. The good stability indicates [33,34,[41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57] the potential applications of the Bi 2 Te 3 nanorods in memory devices. Compared with other nonlinear electronic materials reported in literature, the nanorods aggregates have the highest electrical conductivity sensitivity to the electric field, as show in Figure 3i.…”

“…i) Change comparison of DC conductivity with other nonlinear electrical transport materials at different voltage differences. [ 33,34,41–57 ]…”

“…h) Change of Fermi level within the band structure of TI nanoroads after applying voltage. i) Change comparison of DC conductivity with other nonlinear electrical transport materials at different voltage differences [33,34,[41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57].…”

Electrical Insulation and Radar-Wave Absorption Performances of Nanoferrite/Liquid-Silicone-Rubber Composites

“…The process of charge transporting between these localized states is described macroscopically as percolation conductance, which will be exponentially expedited by thermal excitation, as characterized by the conductivity nonlinearity arising in the nanodielectrics with a high filler concentration. According to percolation conductance theory [ 32 ], the polarized interface layer around SrFe 12 O 19 or CIP nanofillers will overlap to form a random conductive network when the concentration of nanofillers in LSR matrix exceeds a percolation threshold, resulting in the percolation conductance which accounts for the nonlinear conductivity of SrFe 12 O 19 /LSR and CIP/LSR nanocomposites [ 33 ]. In addition, the lower compatibility and larger size of nanofiller result in more filler-introduced charge carriers and a greater percolation conductance, respectively, accounting for the higher conductivity of CIP/LSR nanocomposites than that of SrFe 12 O 19 /LSR nanocomposites.…”

Investigating the non‐linear conductivity properties of silicone rubber co‐modified with doped calcium copper titanate @ zinc oxide and grafted glycidyl methacrylate

“…Adjusting the conductivity of the reinforced insulation material increases the degree of adaptability of the reinforced insulation and the conductivity of the main insulation, and this can solve the localised electric field concentration inside cable accessories. [10][11][12][13][14] The conductivity of polymers can be modulated using inorganic fillers such as zinc oxide (ZnO) and silicon carbide (SiC). [15][16][17][18] Chi et al prepared ZnO nano-organic fillers doped with iron ions and incorporated them into EPDM rubber to create composites.…”