Carbon Nanotube Aqueous Dispersion With Shear-Thinning Gel Network
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing dispersions of single-walled and double-walled carbon nanotubes face challenges in achieving high stability during storage and transportation while maintaining low viscosity during processing, which is necessary for producing high-quality lithium-ion battery electrodes.
Innovation Solution
A dispersion comprising single-walled and/or double-walled carbon nanotubes and a gelling agent, characterized by a specific weight ratio and rheological properties, forms a pseudoplastic fluid with high viscosity at rest and low viscosity under processing conditions, achieved through a production method involving alternating stages of mechanical processing and resting periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbon nanotubes are allowed to agglomerate into long and thick bundles to ensure high electrical conductivity, then electrical conductivity of the electrode is improved, but stability of the dispersion deteriorates with higher rate of sedimentation
Solution Approach 1:
The patent applies parameter changes by modifying the surface properties of carbon nanotubes through oxidation treatments, introducing functional groups that alter interfacial interactions. This changes the aggregation behavior from strong bundling to controlled dispersion, achieving both conductivity and stability through modified surface chemistry parameters
Solution Approach 2:
The patent introduces surfactants and dispersing agents as intermediary substances that mediate between carbon nanotubes and the dispersion medium. These intermediaries prevent excessive agglomeration while maintaining conductive networks, resolving the contradiction between bundle formation for conductivity and dispersion stability
2Stability of the object's composition
If dispersing agents and surfactants are used to prevent agglomeration of carbon nanotubes, then stability of the dispersion is improved, but electrical conductivity deteriorates due to reduced long bundles
Solution Approach 1:
The patent modifies the parameters of dispersing agents by selecting specific types with optimized molecular structures and concentrations. This allows maintaining dispersion stability while preserving sufficient nanotube bundling for electrical conductivity through parameter optimization
Solution Approach 2:
The patent applies partial action by using controlled amounts of dispersing agents that prevent excessive agglomeration but do not completely eliminate bundle formation. This partial intervention maintains both stability and conductivity by allowing some bundling while preventing sedimentation
3Strength
If concentration of nanotubes and bundles is increased to improve electrical conductivity, then electrical conductivity of the electrode is improved, but viscosity of the dispersion increases making processing difficult
Solution Approach 1:
The patent changes the rheological parameters of the dispersion by introducing viscosity modifiers and optimizing nanotube concentration. This allows maintaining high electrical conductivity through sufficient nanotube content while managing viscosity for processability through parameter control
Solution Approach 2:
The patent introduces viscosity-reducing agents as intermediaries that facilitate processing of high-concentration nanotube dispersions. These intermediaries reduce friction and resistance to flow, enabling easy processing while maintaining high nanotube content for conductivity
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 dispersion ensures long-term storage and transportation stability with minimal agglomeration, while allowing for efficient processing into electrode slurries and electrodes, enhancing the quality and performance of lithium-ion batteries.
Implementation Method 1
the dispersion contains gel particles formed by agglomerates of gelling agent molecules physically bound into a weak gel network by single-walled and/or double-walled carbon nanotubes
Implementation Method 2
characterized by a specific weight ratio and rheological properties, forms a pseudoplastic fluid with high viscosity at rest and low viscosity under processing conditions
Implementation Method 3
a production method involving alternating stages of mechanical processing and resting periods
Implementation Method 4
causes higher rate of sedimentation of dispersed carbon nanotube agglomerates
Data Source
AI summary
A dispersion containing water, a gelling agent, and 0.3 to 2 wt. % of single-walled and/or double-walled carbon nanotubes with a weight ratio of the single-walled and/or double-walled carbon nanotubes to the gelling agent at least 0.05 and not more than 10, wherein the dispersion contains gel particles formed by agglomerates of gelling agent molecules physically bound into a weak gel network by single-walled and/or double-walled carbon nanotubes. Also disclosed a method for producing a dispersion, a method for producing cathode and anode slurries, cathode and anode slurries, and a cathode and an anode are provided. The problems of obtaining an aqueous dispersion of single-walled and/or double-walled carbon nanotubes with both high stability during storage and transportation and low viscosity under various processes of its application, and producing electrode slurries and then lithium-ion battery electrodes, are addressed.