SWCNT Electrode Composition for Uniform Conductive Networks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing secondary battery electrodes face limitations in achieving uniform distribution and high electrical conductivity due to poor dispersibility and adhesion of conductive agents like carbon nanotubes, leading to suboptimal performance and life characteristics.
Innovation Solution
An electrode active material layer is developed using a conductive agent dispersion of sonicated bundle-type single-walled carbon nanotubes bonded together, with polyvinylidene fluoride, to form a network structure that enhances adhesion and conductivity, improving the distribution and connectivity of carbon nanotubes within the electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If line-type conductive agent such as carbon nanotube is used to improve electrical conductivity, then electrical conductivity is excellent, but dispersibility in slurry is low due to bundle type growth, resulting in poor coatability and non-uniform distribution
Solution Approach 1:
The carbon nanotubes are segmented into small bundles containing 2 to 50 units, rather than using large bundles or individual nanotubes. This segmentation achieves optimal balance between maintaining electrical conductivity (through sufficient nanotube connectivity) and improving dispersibility (through reduced bundle size), enabling uniform distribution in the electrode slurry while preserving excellent conductive properties
Solution Approach 2:
The invention changes the critical parameter of bundle size to a specific range (2 to 50 units) through controlled sonication treatment. This parameter optimization resolves the contradiction by finding the sweet spot where bundles are small enough to disperse uniformly but large enough to maintain effective electrical conductivity pathways
2Stability of the object's composition
If functional group is introduced to improve dispersibility of carbon nanotube, then dispersibility is improved, but surface side reaction occurs, deteriorating electrochemical properties
Solution Approach 1:
Polyvinylidene fluoride serves as an intermediary substance that facilitates the dispersion of carbon nanotube bundles in the slurry without requiring functional group modification of the nanotubes themselves. This mediator approach improves dispersibility while preserving the electrochemical properties of the carbon nanotubes, as no reactive functional groups are introduced to the nanotube surface
3Stability of the object's composition
If point-type conductive agent such as carbon black is used, then dispersibility is good, but electrical conductivity improvement is insufficient
Solution Approach 1:
The invention creates a composite structure combining small bundles of single-walled carbon nanotubes (2 to 50 units) with polyvinylidene fluoride binder. This composite material exhibits both excellent dispersibility (like point-type agents) and superior electrical conductivity (like line-type agents), effectively combining the advantages of both approaches while avoiding their respective disadvantages
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 approach results in improved electrical conductivity, reduced electrode resistance, and enhanced electrochemical performance and life characteristics of the battery, even with a small amount of conductive agent, by forming a robust conductive path and strong adhesion.
Implementation Method 1
a carbon nanotube structure in which 2 to 5,000 single-walled carbon nanotube units are bonded to each other
Implementation Method 2
the conductive agent includes a carbon nanotube structure in which 2 to 5,000 single-walled carbon nanotube units are bonded to each other
Implementation Method 3
the electrode active material layer includes an electrode active material; polyvinylidene fluoride; and a conductive agent
Data Source
Figure 1(a)~1(d)
Figure 2
Figure 3~4
AI summary
An electrode includes an electrode active material, wherein the electrode active material layer includes an electrode active material, polyvinylidene fluoride, and a conductive agent, wherein the conductive agent includes a carbon nanotube structure in which 2 to 5,000 single-walled carbon nanotube units are bonded to each other, and the carbon nanotube structure is included in an amount of 0.01 wt% to 0.5 wt% in the electrode active material layer. A secondary battery including the same, and a method of preparing the electrode are also provided.