Low-Defect Carbon Nanotube Sludge for Conductive Battery Slurries
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for dispersing single-walled and double-walled carbon nanotubes in polymer matrices or electrode slurries often destroy their inherent electrical conductivity and structural integrity, leading to reduced dispersibility and stability, necessitating additional processes to restore these properties.
Innovation Solution
A method involving the use of alkali metal salts and specific acids to de-bundle carbon nanotubes under controlled shear stress, followed by neutralization and washing, results in a low-defect carbon nanotube sludge that can be directly dispersed in polymer binders without additional dispersants, maintaining high crystallinity and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If physical grinding methods or chemical oxidation methods are used to de-bundle carbon nanotubes, then dispersion stability is improved, but the sp2 hexagonal carbon ring structure is destroyed and electrical conductivity decreases
Solution Approach 1:
The patent replaces mechanical grinding methods (ultrasonic dispersion, high-pressure homogenization) with a chemical method using acid treatment and alkali metal salts. This substitution allows de-bundling to occur through chemical interaction rather than mechanical force, preserving the sp2 carbon structure and maintaining electrical conductivity while achieving dispersion stability.
Solution Approach 2:
The patent changes the chemical environment parameters by introducing acid treatment followed by alkali metal salt addition. This parameter change creates optimal conditions for de-bundling carbon nanotubes without damaging their structure, achieving both dispersion stability and conductivity preservation simultaneously.
2Stability of the object's composition
If non-conductive dispersants are used to improve dispersibility, then dispersion is enhanced, but interfacial resistance increases and structural defects are formed
Solution Approach 1:
The patent uses acid-treated carbon nanotubes and alkali metal salts as intermediaries to achieve dispersion without non-conductive dispersants. The acid treatment creates surface groups that facilitate dispersion, while the alkali metal salts further enhance dispersibility through electrostatic repulsion, all while maintaining the conductive sp2 structure.
Solution Approach 2:
The patent changes the surface chemical parameters of carbon nanotubes through acid treatment, creating oxygen-containing functional groups that improve dispersibility. The subsequent addition of alkali metal salts further modifies surface charge parameters, enabling effective dispersion without compromising electrical conductivity.
3Stability of the object's composition
If carbon nanotubes are dispersed in polymer matrices using mechanical dispersion methods, then dispersion is achieved, but the carbon nanotube structure is damaged and additional reduction processes are required
Solution Approach 1:
The patent replaces mechanical dispersion methods that damage carbon nanotube structures with a chemical treatment approach using acid and alkali metal salts. This substitution achieves effective dispersion while preserving the sp2 structure, eliminating the need for additional reduction processes and simplifying the overall manufacturing process.
4Stability of the object's composition
If high shear stress is applied to carbon nanotubes to de-bundle them, then dispersion is improved, but the sp2 structure is destroyed and electrical conductivity decreases
Solution Approach 1:
The patent replaces high shear stress mechanical de-bundling methods with a chemical treatment approach using acid and alkali metal salts. This substitution achieves effective de-bundling and dispersion through chemical interaction rather than mechanical force, preserving the sp2 carbon structure and maintaining high electrical 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 process enables high-conductivity, low-defect carbon nanotubes to form stable electrical networks with silicon-based active materials, enhancing the performance and longevity of lithium secondary batteries by minimizing structural defects and eliminating the need for post-reduction processes.
Implementation Method 1
de-bundling the bundles to realize carbon nanotube dispersion in a dispersion medium by making such strong van der Waals attraction weak
Implementation Method 2
strong van der Waals attraction resulting from small diameters and high aspect ratios
Implementation Method 3
applying shear stress to de-bundle the introduced carbon nanotubes
Implementation Method 4
acid treatment in which acid and an alkali metal salt are mixed to keep the carbon nanotubes from being oxidized or keep carbon sp2 bonds on the surface from being broken
Implementation Method 5
neutralizing and washing the de-bundled carbon nanotubes
Data Source
AI summary
The present invention relates to a low-defect carbon nanotube sludge and a preparation method therefor, a conductive composite material based on the low-defect carbon nanotube, a negative electrode slurry using same, a negative electrode, and a lithium secondary battery, and has the technical gist of comprising carbon nanotubes that have crystallinity while satisfying relational expression 1 below. [relational expression 1] 5≤IG/ID≤50 (wherein IG/ID is a value calculated as a ratio of a maximum peak intensity (IG) measured at 1,580±50 cm−1 to a maximum peak intensity (ID) measured at 1,360±50 cm−1 in a wavenumber region of a Raman spectrum.)