Doped Carbon Nanotube Wire Structure for Copper-Level Conductivity

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Carbon nanotube composites exhibit higher resistivity compared to copper and aluminum, limiting their effectiveness as wire materials, especially in high-temperature environments, and existing doping methods do not adequately address conductivity and temperature resistance issues.

Innovation Solution

A carbon nanotube composite with a higher ratio of double-walled or triple-walled carbon nanotubes and strategically introduced elements, such as iodine, arranged in specific configurations to enhance conductivity and reduce temperature-induced lattice vibrations, achieving resistivity comparable to copper or aluminum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If carbon nanotube composite is used as wire material, then lightweighting is achieved, but resistivity is higher than copper and aluminum

Engineering Contradiction:
Improvewire massVSAvoidelectrical conductivity
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent changes the structural parameters of carbon nanotubes by using double-walled or triple-walled structures with specific outer diameter ratios, and modifies the electrical parameters through doping treatments with alkali metals or alkaline earth metals, achieving resistivity comparable to copper and aluminum while maintaining lightweight properties

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure by combining multiple carbon nanotubes with specific wall structures into bundles, and further composites them with dopant materials, achieving synergistic effects that improve electrical conductivity while maintaining the inherent lightweight advantage of carbon nanotubes

Inventive Principle:
Principle #40Composite materials

2Reliability

If doping treatment is applied to carbon nanotube, then conductivity is improved, but temperature resistance is insufficient

Engineering Contradiction:
Improveelectrical conductivityVSAvoidtemperature resistance
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent optimizes the doping concentration parameters within specific ranges (0.1-5.0 at% for alkali metals, 0.05-3.0 at% for alkaline earth metals) and controls the structural parameters of carbon nanotubes, achieving a balance between conductivity enhancement and temperature resistance that prevents excessive lattice vibration at elevated temperatures

Inventive Principle:
Principle #35Parameter changes

3Reliability

If cross-sectional area of aluminum wire is increased to match copper wire conductivity, then electrical properties are improved, but wire mass is still lighter than copper

Engineering Contradiction:
Improveelectrical conductivityVSAvoidwire mass
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent fundamentally changes the material parameters by using carbon nanotubes with inherently lower density than aluminum, combined with structural optimizations and doping treatments that achieve copper-level conductivity, resulting in wires that are significantly lighter than both copper and aluminum wires while maintaining superior electrical properties

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution significantly improves electrical conductivity and resistance stability in high-temperature environments, achieving lower resistivity and better performance than conventional carbon nanotube composites, with enhanced carrier generation and doping effects.

Implementation Method 1

a doping treatment is performed by sputtering, spraying, immersing, or gaseous phase introduction, to produce a carbon nanotube wire having a dopant containing iodine, silver, chlorine, bromine, fluorine, gold, copper, aluminum, sodium, iron, antimony, arsenic, or a combination thereof

Methodology Applied
Scientific EffectDoping: Dopants

Implementation Method 2

a carbon nanotube simple substance exhibits higher conductivity than that of copper... a method for controlling the network structure (chirality) of carbon nanotubes which are constitutional units and subjecting the carbon nanotubes to a doping treatment is proposed as one of methods for improving the conductivity of a carbon nanotube aggregate

Methodology Applied
Scientific EffectLattice vibration:

Data Source

PatentEP3434644B1Carbon nanotube composite and carbon nanotube wire
Publication Date: 2024.05.22 FURUKAWA ELECTRIC CO LTD
  • EP3434644B1 patent drawingFigure 1A~1F
  • EP3434644B1 patent drawingFigure 2
  • EP3434644B1 patent drawingFigure 3A~3B

AI summary

Provided is a carbon nanotube composite which can achieve a resistance even lower than that of a conventional carbon nanotube composite and achieve resistivity equivalent to that of copper or aluminum, and can greatly improve electrical properties even in high temperature environments. A CNT composite (11) includes: a CNT bundle (11A) including a plurality of CNTs (11a), (11a), ..., that are bundled, each having a double-walled structure; and a group of elements of other type (12) introduced in an aligned manner into a gap portion (11B) between the plurality of CNTs (11a), (11a), ....