Negative Electrode Slurry Composition for Stable CNT Dispersion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing slurry compositions for negative electrodes in secondary batteries, particularly those using carbon nanotubes, face challenges in achieving both stability of the coating liquid and conductive performance, with issues such as insufficient dispersion, long dispersion times, and electrode peeling during processing.
Innovation Solution
A slurry composition for negative electrodes containing carbon nanotubes, a conductive material, a negative electrode active material, and a binder component, utilizing two types of carboxymethyl cellulose with specific molecular weight ranges, ensures high stability and low resistance when formed into an electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon nanotubes are used in the slurry composition, then conductive performance is improved, but stability of the coating liquid deteriorates
Solution Approach 1:
A specific dispersant is introduced as an intermediary substance between carbon nanotubes and the coating liquid. This dispersant mediates the interaction by adsorbing onto carbon nanotube surfaces while maintaining compatibility with the liquid medium, thereby preventing aggregation and maintaining both conductive performance and coating stability.
Solution Approach 2:
The molecular weight of the dispersant is precisely controlled within the range of 300,000 to 1,000,000. This parameter optimization ensures the dispersant has sufficient molecular size to effectively wrap and stabilize carbon nanotubes, while maintaining appropriate solution viscosity and stability. The specific molecular weight range balances dispersion capability with coating liquid stability.
2Reliability
If dispersant is added to improve dispersion of carbon nanotubes, then conductive network formation is improved, but resistance value increases
Solution Approach 1:
The molecular weight of the dispersant is precisely controlled within the range of 300,000 to 1,000,000. This parameter optimization ensures the dispersant has sufficient molecular size to effectively wrap and stabilize carbon nanotubes, while maintaining appropriate solution viscosity and stability. The specific molecular weight range balances dispersion capability with minimal impact on resistance.
Solution Approach 2:
The dispersant selectively interacts with carbon nanotube surfaces through localized adsorption, providing conductive pathways while maintaining low resistance. The dispersant's molecular structure is designed to create conductive networks at specific locations (carbon nanotube interfaces) without introducing excessive resistance throughout the entire electrode matrix.
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 composition provides a stable and conductive negative electrode with low resistance values, suitable for lithium ion batteries, maintaining stability during storage and efficient electrode formation.
Implementation Method 1
the dispersant includes carboxymethyl cellulose having a mass average molecular weight of 300000 or less or a metal salt thereof, and carboxymethyl cellulose having a mass average molecular weight of 1000000 to 3000000 or a metal salt thereof
Implementation Method 2
a negative electrode for a secondary battery in which a negative electrode mixture layer is formed by allowing a negative electrode mixture coating material to adhere onto a current collector
Data Source
AI summary
There is provided a slurry composition for a negative electrode of a secondary battery suitable for producing a battery such as a lithium ion battery and an electrode, which has high stability and is capable of forming a negative electrode having a low resistance value when formed into an electrode, even when the slurry composition for a negative electrode of a secondary battery uses carbon nanotubes. A slurry composition for a negative electrode of a secondary battery according to the present disclosure includes at least carbon nanotubes, a conductive material, a negative electrode active material, a dispersant, and a binder component. The dispersant includes carboxymethylcellulose having a mass average molecular weight of 300000 or less or a metal salt thereof, and carboxymethylcellulose having a mass average molecular weight of 1000000 to 3000000 or a metal salt thereof.