Carbon Nanotube Dispersion for Stable Battery Slurry Conductivity
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Solution Overview
Problem
Carbon nanotubes, despite their high electrical conductivity, suffer from poor dispersibility in electrode slurry compositions, leading to decreased conductivity and performance of secondary batteries over time.
Innovation Solution
A carbon nanotube dispersion is formulated using a nonionic polymer with a weight average molecular weight of 4,000 g/mol to 30,000 g/mol and an anionic polymer with a sulfonic acid group, in a weight ratio of 5:1 to 1:5, to enhance dispersibility and minimize viscosity changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon nanotubes are used as a conductive agent, then electrical conductivity is improved, but dispersibility in slurry deteriorates
Solution Approach 1:
The patent introduces a specific dispersant as an intermediary substance between carbon nanotubes and slurry components. This dispersant mediates the interaction by reducing aggregation forces between carbon nanotubes and improving their compatibility with the slurry medium, thereby resolving the contradiction between maintaining high conductivity and achieving good dispersibility
Solution Approach 2:
The patent changes key parameters including the molecular weight of the dispersant (4,000-30,000 g/mol), the weight ratio of dispersant to carbon nanotubes (1:5 to 5:1), and the chemical structure (specifically incorporating sulfonic acid groups). These parameter changes optimize both dispersibility and electrical conductivity simultaneously
2Reliability
If carbon nanotubes are used as a conductive agent, then initial conductivity is improved, but conductivity over time deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-dispersing carbon nanotubes with the specific dispersant formulation before incorporating them into the electrode slurry. This preliminary dispersion treatment ensures that carbon nanotubes are properly distributed and stabilized in advance, preventing subsequent aggregation and maintaining conductivity over the battery's operational lifetime
Solution Approach 2:
The dispersant acts as a protective intermediary that maintains the separation and distribution of carbon nanotubes over time. This intermediary layer prevents direct contact and aggregation between carbon nanotube surfaces, thereby preserving the conductive network structure throughout the battery's service life
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 solution improves the dispersibility and electrical conductivity of carbon nanotubes, resulting in enhanced performance and stability of secondary batteries, including improved initial discharge capacity and high-rate discharge characteristics.
Implementation Method 1
a first dispersant including a nonionic polymer having a weight average molecular weight of 4,000 g/mol to 30,000 g/mol
Implementation Method 2
a second dispersant including an anionic polymer having a sulfonic acid (salt) group
Data Source
AI summary
The present invention provides a carbon nanotube dispersion including carbon nanotubes; a first dispersant including a nonionic polymer having a weight average molecular weight of 4,000 g/mol to 30,000 g/mol; and a second dispersant including an anionic polymer having a sulfonic acid (salt) group, wherein a weight ratio of the first dispersant to the second dispersant is 5:1 to 1:5; a method of preparing the carbon nanotube dispersion; and an electrode slurry composition and secondary battery including the carbon nanotube dispersion.