Carbon Nanotube Composite Particles for Uniform Electrode Dispersion
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Solution Overview
Problem
Existing electrically conductive materials, such as carbon nanotubes, are difficult to uniformly disperse in electrode coating films due to their small primary particle size and strong cohesive force, leading to uneven distribution and poor electrical conductivity, which affects the performance of lithium ion secondary cells.
Innovation Solution
The use of carbon nanotubes and dispersants in a specific ratio and particle size distribution, along with a method involving wet pulverization, dispersion medium removal, and classification, to create electrically conductive material composite particles with a maximum particle size of 150 µm or less and a dispersant content between 1 to 200 parts by mass, ensuring uniform dispersion and improved electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon nanotubes are used as electrically conductive material, then electrical conductivity is improved, but uniform dispersibility deteriorates due to small primary particle size and strong cohesive force
Solution Approach 1:
A dispersant is introduced as an intermediary substance between carbon nanotubes and the dispersion medium. The dispersant adsorbs onto the carbon nanotube surface, providing steric or electrostatic repulsion that prevents aggregation and enables uniform dispersion while maintaining the high electrical conductivity of the carbon nanotubes.
Solution Approach 2:
The invention creates a composite structure consisting of carbon nanotubes combined with dispersant molecules. This composite approach allows the carbon nanotubes to maintain their conductive properties while the dispersant component provides compatibility with the dispersion medium and prevents aggregation through surface modification.
2Stability of the object's composition
If electrically conductive material dispersion paste is used to improve dispersibility, then uniform distribution is improved, but environmental load increases due to large amount of organic solvent required
Solution Approach 1:
The invention changes the concentration parameter of the dispersant relative to carbon nanotubes (specific ratio range) to achieve effective dispersion with minimal organic solvent. By optimizing the dispersant-to-carbon nanotube ratio, the system achieves stable dispersion using smaller amounts of environmentally harmful organic solvents.
3Stability of the object's composition
If electrically conductive material dispersion paste is used, then dispersibility is improved, but long-term stability deteriorates due to sedimentation and reaggregation properties
Solution Approach 1:
The dispersant acts as a protective intermediary that continuously adsorbs onto carbon nanotube surfaces, preventing sedimentation and reaggregation over time. This intermediary layer maintains colloidal stability and prevents the carbon nanotubes from settling or re-aggregating, ensuring long-term stability of the dispersion.
4Reliability
If carbon nanotubes are directly used in electrode coating film, then electrical conductivity is improved, but uniform distribution deteriorates leading to poor cell performance
Solution Approach 1:
The dispersant serves as a mediator that enables uniform distribution of carbon nanotubes in the electrode coating film. By adsorbing onto the nanotube surfaces, the dispersant prevents aggregation and ensures homogeneous distribution throughout the coating, which is essential for achieving uniform electrical conductivity and good cell performance.
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 composite particles effectively disperse carbon nanotubes in electrode coating films, enhancing the electrical conductivity and performance of lithium ion secondary cells by maintaining uniform distribution and stability over time.
Implementation Method 1
electrically conductive material composite particles containing a carbon nanotube and a dispersant
Data Source
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AI summary
Electrically conductive material composite particles contain a carbon nanotube and a dispersant. The electrically conductive material composite particles have a maximum particle size of 150 µm or less, and a mixing amount of the dispersant is 1 part by mass or more and 200 parts by mass or less with respect to 100 parts by mass of the carbon nanotube.