Negative Electrode Slurry with Dual-CMC CNT Dispersion Stability
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Solution Overview
Problem
Existing slurry compositions for negative electrodes in secondary batteries, particularly those using carbon nanotubes, face challenges with stability and conductive performance, leading to 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, achieves high stability and low resistance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon nanotubes are used as negative electrode material, then conductive performance is improved, but dispersion stability deteriorates
Solution Approach 1:
The patent uses carboxymethyl cellulose (CMC) as an intermediary substance to mediate between carbon nanotubes and the electrode matrix. The CMC forms a stable dispersion medium that allows carbon nanotubes to be uniformly distributed throughout the negative electrode, solving both the conductive performance and dispersion stability issues simultaneously
Solution Approach 2:
The patent creates a composite material system combining carbon nanotubes, carboxymethyl cellulose, and electrode active materials. This composite approach allows the carbon nanotubes to provide conductivity while the CMC matrix maintains dispersion stability and prevents aggregation during storage and processing
2Reliability
If carbon nanotube dispersion is used, then conductive network formation is improved, but dispersion time increases
Solution Approach 1:
The patent performs preliminary dispersion of carbon nanotubes in carboxymethyl cellulose solution before mixing with other electrode materials. This pre-dispersion step ensures that carbon nanotubes are already well-distributed and ready for rapid incorporation into the final electrode mixture, significantly reducing the overall dispersion time required
3Reliability
If carbon nanotubes are added to slurry, then electrode conductivity is improved, but electrode peeling during processing occurs
Solution Approach 1:
The carboxymethyl cellulose acts as a binding intermediary that adheres carbon nanotubes to the electrode active materials and current collector. This intermediary binding mechanism maintains strong electrode adhesion while preserving the conductive benefits of carbon nanotubes, preventing peeling during electrode processing
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 ensures stable dispersion and formation of electrodes with low resistance values, maintaining stability over time and enhancing conductivity, suitable for lithium ion batteries.
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
carbon nanotubes have been used because, by using a carbon nanotube dispersion or the like as a negative electrode material, it is possible to achieve good conductive performance, to reduce electrode resistance, and to efficiently form a conductive network
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.