Carbon Nanotube Coated Conductors

Abstract

A novel approach based on conventional solution-coating and wire-drawing processes has been employed for the production of carbon nanotube (CNT) coated conductors. The solution process employs a mesoscopic building block, a CNT fibril dispersion formed in acid from forest-grown, long-length multiwall CNTs, to help bridge the transition from nanomaterials to thick, highly aligned technical coatings. The coatings are formed onto a roughened copper wire former through dip-coating. The roughened surface provides for mechanical attachment between the CNT coating and copper wire core that allows for the composite to be wire-drawn while wet to further shape, densify, and align the CNT coating. The wet chemistry approach offered a facile integration of different CNT and dopant types in the CNT coatings. For the specific process described here, it was observed that the CNT coatings were simultaneously doped with acid and copper nanoparticles. Coated wires were produced with conductivities on par with copper but in an engineered material that is lighter than the pure metal analogue. Dense coatings up to 90 μm in thickness were made that comprised up to 60% of the wire cross-sectional area and enabled composite densities to dip below half that of copper. The CNT coated wires had overall resistivities in the range 2.1–5 μΩ·cm, with specific conductivities relative to copper as high as 108%. The ubiquitous nature of the solution coating and conventional wire drawing processes may enable a novel approach to the light-weighting of advanced conductors for a broad range of applications.

An Axially Continuous Graphene–Copper Wire for High‐Power Transmission: Thermoelectrical Characterization and Mechanisms

“…A carbon-metal composite is a promi sing alternative to conventional Cu/Al wires due to their improved current-carrying capability and enhanced chemical resistance. [5][6][7] Nano/microscale carbon materials, e.g., carbon nanotubes and graphene flakes, have been mixed within a metal matrix to develop effective carbon-metal composites for electrical applications. The general goal for these approaches [4,8] is to integrate the thermoelectrical advantages of carbon constituents, namely excellent current density limit (>10 8 A cm -2 ), electron mobility (15 000 cm 2 V -1 s -1 ), and thermal conductivity (≈5000 W m -1 K -1 ), with metals that have high charge-carrier density (8.491 × 10 28 carriers m -3 for Cu) for advanced power transmission.…”

“…Efforts have been put forth to incorporate a continuous graphene sheet as a conductive shell on a microscale Cu wire to improve electrical conductivity and oxidation resistance of the carbon-shell-Cu-core composite structure, e.g., 10% improvement is observed in carbon nanotube-coated, 1 mm-diameter Cu wires. [6] However, the fundamental mechanisms of the coupled thermal and electrical behavior of axially continuous graphene-copper composites at the microscale are not yet fully understood unlike nanoscale carbon-metal composites. [24][25][26][27] In this regard, we develop the axially continuous graphenecopper (ACGC) composite wires using microscale Cu wires with diameters ranging from 10 to 80 µm.…”

Recent Advances of Carbon-Based Flexible Strain Sensors in Physiological Signal Monitoring

“…Polymeric materials are widely used as flexible substrates for flexible sensors due to their excellent flexibility, good thermal stability, and chemical stability, for example, polydimethylsiloxane (PDMS), , Ecoflex, − polyurethane (PU), , polyethylene terephthalate (PET), , polyimide (PI), , rubber, , and so on. Conductive filled materials, such as carbon nanotubes (CNTs), − graphene (including rGO), ,,− metal nanoparticles and nanowires, − conductive polymers, and so on have been intensively studied in recent years. Using the conductive filled nanoparticles, a high sensitivity of sensors was reported to be easy to achieve.…”

Advanced Electrical Conductors: An Overview and Prospects of Metal Nanocomposite and Nanocarbon Based Conductors

“…Novel approaches for fabricating CNT conductor wires have been also investigated. [29,30] In general, electrical conductivity of CNT fibers can be improved by up to ten times via acid, [31] iodine, [32] or metal nanoparticle [24] doping. Doped nanocarbon fibers contain only a few weight percent of a metal or metal halide, [18] in contrast to metal-carbon nanocomposites that are largely metal-based.…”

“…Specific conductivity is σ / ρ = ( L / RA )/( M / LA ), which can be simplified to σ / ρ = ( L 2 / RM ). [ 29 ]…”