High Ampacity Carbon Nanotube Materials

Abstract

Constant evolution of technology is leading to the improvement of electronical devices. Smaller, lighter, faster, are but a few of the properties that have been constantly improved, but these developments come hand in hand with negative downsides. In the case of miniaturization, this shortcoming is found in the inherent property of conducting materials—the limit of current density they can withstand before failure. This property, known as ampacity, is close to reaching its limits at the current scales of use, and the performances of some conductors such as gold or copper suffer severely from it. The need to find alternative conductors with higher ampacity is, therefore, an urgent need, but at the same time, one which requires simultaneous search for decreased density if it is to succeed in an ever-growing electronical world. The uses of these carbon nanotube-based materials, from airplane lightning strike protection systems to the microchip industry, will be evaluated, failure mechanisms at maximum current densities explained, limitations and difficulties in ampacity measurements with different size ranges evaluated, and future lines of research suggested. This review will therefore provide an in-depth view of the rare properties that make carbon nanotubes and their hybrids unique.

Fabrication of High Specific Electrical Conductivity and High Ampacity Carbon Nanotube/Copper Composite Wires

“…where I max is the maximum current before failure and A cs is the cross‐section area of the wire. Figure 5b presents SEC versus ampacity which compares our results with other published work on CNTs/Cu wires, [ 96,98 ] polycrystalline metals such as Cu, Au, Ag, and Al, [ 8,126,127 ] individual multi and single‐walled carbon nanotubes [ 7,8,128 ] and our measurements of commercially available super‐acid spun CNTs filaments DEXMAT CO., and pure Cu wires (ϕ 0.05 mm, the scientific wire co. Essex, UK).…”

A Meta‐Analysis of Conductive and Strong Carbon Nanotube Materials

“…Electromigration is the diffusion of metal ions due to momentum transfer from charge carriers at high currents; it was confirmed by the movement of scratch marks on a gold wire subjected to high current densities. [62,242,244] Electromigration results in the formation of voids and hillocks in conducting pathways, and can cause failure well before the conductors' melting points (fusing currents) are reached. [245,246] These electromigration effects become significant in sub-micrometer interconnects due to their narrow channel widths and thicknesses, increasing chances of failure.…”

“…There are many useful literature reviews on CNT-based materials, including general review of CNT cables [1,11,58] and transparent conductive films, [59] mechanical properties and composites, [60,61] metal CNT composites, [23] thermal conductivity and ampacity, [62] thermoelectrics, [63] fiber production, [20,21,[64][65][66][67] transport mechanisms and intrinsic properties, [68][69][70][71][72] armchair CNTs, [73] double-wall CNTs (DWCNTS), [74,75] electronic and helicity sorting, [76] and doping. [77] There are also useful reviews on carbon fiber, [78] graphitic intercalation compounds, [32,35,79,80,81] conductive polymers, [82,83] and Lewis super-acids.…”

Copper–CNT interfacing with Cu-doped polydopamine in CNT carpet: copper nucleation and resistance decrease upon soft annealing

“…[3][4][5] Still, these results are controversial for such a material, acknowledging that the most recent literature discloses ampacity gains/losses ranging from 30% loss to 36% gain. [6][7][8] Such a large range of results demands further investigation related to the mechanisms governing the conductivity and ampacity of these materials. Among the critical parameters governing the conductivity and the ampacity of such composites, the electronic interactions of copper and CNT orbitals are instrumental.…”