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

Abstract

Carbon nanotube (CNT)/copper composites offer promise as lightweight temperature-stable electrical conductors for future electrical and electronic devices substituting copper. However, clarifying how constituent nanotube structures influence CNT/Cu electrical performances has remained a major research challenge. Here, we investigate the correlation between the CNT/Cu electrical performances and nanotube structure by preparing and characterizing composites containing nanotubes of different structural attributes. We prepared three types of composites—single-wall (SW)-CNT/Cu wires, SW-CNT/Cu pillars, and multi-wall (MW)-CNT/Cu wires. The composites were fabricated from the corresponding CNT templates by two-step Cu electrodeposition, which retains template nanotube attributes through the fabrication process. The nanotube characteristics (diameter, G/D, alignment, etc.) in each template as well as the internal structure and electrical performances of the corresponding composites were characterized. SW-CNT/Cu wires and pillars outperformed MW-CNT/Cu wires, showing ≈ 3× higher room-temperature four-probe conductivities (as high as 30–40% Cu-conductivity). SW-CNT/Cu also showed up to 4× lower temperature coefficients of resistances i.e., more temperature-stable conductivities than MW-CNT/Cu. Our results suggest that few-walled small-diameter nanotubes can contribute to superior temperature-stable CNT/Cu conductivities. Better CNT crystallinity (high G/D), fewer nanotube ends/junctions, and nanotube alignment may be additionally beneficial. We believe that these results contribute to strategies for improving CNT/Cu performances to enable the real-world application of these materials as Cu substitutes.

Investigation of using CNT and Cu/CNT Wires for Replacing Cu for Power Electronics and Electrical Applications

“…MWCNT density of 40%-45% in Cu/CNT composite provides excellent electrical properties with lower density. 58,59 Cu/MWCNT fibre has the approximate diameter 22 nm and 500 μm long. These fibres are bundled together and made in to long conductive wires with required higher thickness.…”

“…Figure 4a shows the SEM image of the Cu/MWCNT composite. 58,59 The Figs. 4b and 4c shows the Cu/MWCNT fibre and the wire respectively.…”

“…CNT concentration is approximately 45% in Cu/CNT composite. 58,59 The calculated values of Table II are obtained through the Eqs. 1 to 11.…”

Correlation of structure development and electric characteristics within high pressure torsion processed copper

“…ii) to manufacture copper-based composites with additions of strengthening elements (e. g. powder-based copper composites with chromium, alumina, or carbon and its nanotubes, copper clad composites with aluminum, magnesium and aluminum, niobium, high entropy alloys, etc. [3][4][5][6][7][8]. iii) to use optimized thermomechanical (deformation) treatment (e. g. via rotary swaging, or methods of severe plastic deformation) [9][10][11][12].…”