A Meta‐Analysis of Conductive and Strong Carbon Nanotube Materials

Abstract

A study of 1304 data points collated over 266 papers statistically evaluates the relationships between carbon nanotube (CNT) material characteristics, including: electrical, mechanical, and thermal properties; ampacity; density; purity; microstructure alignment; molecular dimensions and graphitic perfection; and doping. Compared to conductive polymers and graphitic intercalation compounds, which have exceeded the electrical conductivity of copper, CNT materials are currently one‐sixth of copper's conductivity, mechanically on‐par with synthetic or carbon fibers, and exceed all the other materials in terms of a multifunctional metric. Doped, aligned few‐wall CNTs (FWCNTs) are the most superior CNT category; from this, the acid‐spun fiber subset are the most conductive, and the subset of fibers directly spun from floating catalyst chemical vapor deposition are strongest on a weight basis. The thermal conductivity of multiwall CNT material rivals that of FWCNT materials. Ampacity follows a diameter‐dependent power‐law from nanometer to millimeter scales. Undoped, aligned FWCNT material reaches the intrinsic conductivity of CNT bundles and single‐crystal graphite, illustrating an intrinsic limit requiring doping for copper‐level conductivities. Comparing an assembly of CNTs (forming mesoscopic bundles, then macroscopic material) to an assembly of graphene (forming single‐crystal graphite crystallites, then carbon fiber), the ≈1 µm room‐temperature, phonon‐limited mean‐free‐path shared between graphene, metallic CNTs, and activated semiconducting CNTs is highlighted, deemphasizing all metallic helicities for CNT power transmission applications.

From Waste Plastics to Carbon Nanotube Audio Cables

“…CNT-based cables show plenty of promise with individual CNT electrical conductivity besting copper, while also having the benefit of lower mass density, owing to the hollow cylindrical nature of the nanotubes [6]. Despite there being several different attempts at making long cables out of individual CNTs [7][8][9][10][11][12][13], the primary issue remains that the starting material with the CNTs is generally a mixed bag when it comes to both the general purity being questionable-owing to the presence of contaminants, such as residual catalyst and amorphous carbon-as well as containing a mix of single-and multi-walled CNTs of different chiralities [14,15] to where there is a sliding scale of metallic to semiconducting CNTs in use.…”

Influence of Carbon Nanotube Attributes on Carbon Nanotube/Cu Composite Electrical Performances

“…Among the samples considered here, MW-CNT/Cu wires show lower electrical conductivites and temperature stabilities than SW-CNT/Cu composites (wires and pillars). The poorer performance of MW-CNT/Cu vs. SW-CNT/Cu could boil down to intrinsically lower conductivities of MW-CNTs and their aggregates [36] as well as geometric factors. For comparable nanotube vol %, small-diameter SW-CNTs afford a higher surface to volume ratio.…”

Carbon-Based Fiber Materials as Implantable Depth Neural Electrodes

“…The second type of CNTFs are f loating catalyst CNT f ibers (fCNTFs), which were spun from the CNT membrane grown with a floating catalyst CVD method using a liquid source of carbon and an iron nanocatalyst ( Zhou et al, 2021 ) (see Supplementary Methods for details). Compared to aCNTFs, fCNTFs have higher content of iron contamination and also higher electrical conductivity ( Bulmer et al, 2021 ). The aCNTFs and fCNTFs used in our work had twisted angles of 25° and 10°, respectively.…”