Carbon Nanotube Dispersion Liquid for Low-Viscosity Battery Electrodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrode conductive additives, such as carbon black, are not highly effective in improving electrical conductivity, requiring excessive amounts that reduce the amount of electrode active materials and battery capacity, while carbon nanotubes offer high conductivity at lower amounts but require a dispersion liquid with low viscosity for improved processability.
Innovation Solution
A carbon nanotube dispersion liquid with a viscosity of 3,000 cPs or less at 25°C and 15 sec−1 shear rate, achieved by combining a first dispersant with an amide group and an acryl-based second dispersant with hydroxyl or carboxyl groups, which reduces aggregation and improves dispersibility and coating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If point-type conductive additives such as carbon black are used, then electrical conductivity is improved, but excessive amounts must be used which reduces the amount of electrode active materials and battery capacity
Solution Approach 1:
The patent changes the physical form parameter of the conductive additive from point-type (carbon black) to tubular structure (carbon nanotubes). This structural parameter change enables achieving the same conductivity improvement effect with much smaller amounts, thus resolving the contradiction between conductivity improvement and preservation of active material quantity.
Solution Approach 2:
The patent uses composite material structure by forming a three-dimensional conductive network using carbon nanotubes that interconnect multiple electrode active material particles. This composite approach creates efficient conductivity pathways without requiring excessive amounts of conductive additive, thereby maintaining high battery capacity.
2Reliability
If carbon nanotubes are used as conductive additives, then high conductivity is achieved with small amounts, but the dispersion liquid has high viscosity which reduces processability
Solution Approach 1:
The patent introduces dispersants as intermediary substances that mediate between carbon nanotubes and the dispersion medium. These dispersants adsorb onto carbon nanotube surfaces, preventing aggregation and significantly reducing the viscosity of the dispersion liquid, thereby improving processability while maintaining the high conductivity benefits of carbon nanotubes.
Solution Approach 2:
The patent changes the chemical composition parameters of the dispersion system by selecting specific dispersants with appropriate molecular structures and concentrations. This parameter optimization reduces inter-tube interactions and dispersion liquid viscosity, enabling easy processing while preserving carbon nanotube conductivity advantages.
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 low-viscosity carbon nanotube dispersion liquid enhances the dispersibility and processability of carbon nanotubes, minimizing aggregation and improving the conductivity and capacity of electrodes in lithium secondary batteries.
Implementation Method 1
a first dispersant having an amide group, and an acryl-based second dispersant having one or more functional groups selected from the group consisting of a hydroxyl group and a carboxyl group
Implementation Method 2
the carbon nanotube dispersion liquid has a viscosity of 3,000 cPs or less at a temperature of 25° C. and a shear rate of 15 sec−1
Data Source
AI summary
The present specification relates to a carbon nanotube dispersion liquid, a method for preparing same, an electrode slurry composition comprising same, an electrode comprising same, and a lithium secondary battery comprising same, the carbon nanotube dispersion liquid comprising: carbon nanotubes; a first dispersant having an amide group; and an acryl-based second dispersant having one or more functional groups selected from the group consisting of a hydroxyl group and a carboxyl group, wherein the viscosity at 25° C. and a shear rate of 15 sec−1 is 3,000 cPs or less.