Battery Electrode Conductive Slurry for Low-Viscosity CNT Dispersion
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Solution Overview
Problem
Carbon nanotubes used as conductive materials in secondary battery electrodes face challenges with low solubility and dispersibility, leading to issues with viscosity and electrical conductivity, particularly when high concentrations are required.
Innovation Solution
A conductive material slurry using a cellulose-based compound and a conductive polymer as dispersants to improve the dispersibility and reduce viscosity, with a weight ratio of conductive material to dispersant optimized between 1:1 to 1:2, allowing for effective dispersion of carbon nanotubes without excessive aggregation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon nanotubes are used as conductive material in secondary battery electrodes, then electrical conductivity and energy density are improved, but solubility and dispersibility deteriorate
Solution Approach 1:
The patent uses a surfactant as an intermediary substance to mediate between the carbon nanotubes and the solvent. The surfactant molecules adsorb onto the carbon nanotube surface, providing steric stabilization and preventing aggregation, thereby improving dispersibility without compromising the electrical conductivity of the carbon nanotubes
2Ease of manufacture
If carbon nanotubes are dispersed in solution, then conductive material can be applied to electrodes, but viscosity increases due to aggregation
Solution Approach 1:
The patent converts the harmful aggregation tendency of carbon nanotubes into a beneficial effect by using the surfactant to control the aggregation at the molecular level. The surfactant forms a protective layer that prevents macroscopic aggregation while maintaining the natural bundled structure of carbon nanotubes, thereby reducing viscosity to manageable levels while preserving conductive network formation on electrodes
3Reliability
If high concentration of conductive material is used, then electrical conductivity improves, but dispersibility and viscosity worsen
Solution Approach 1:
The patent changes the chemical parameters of the dispersion system by introducing surfactant molecules with specific hydrophilic-lipophilic balance (HLB) values. This parameter change allows higher concentrations of carbon nanotubes to be dispersed by adjusting the surfactant concentration and type, thereby achieving high conductivity without sacrificing dispersibility
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 a conductive material slurry with low viscosity and sheet resistance, enhancing the manufacturing efficiency and performance of secondary battery electrodes by ensuring better dispersion and conductivity of carbon nanotubes.
Implementation Method 1
a dispersant for dispersing the conductive material, wherein the dispersant includes a cellulose-based compound and a conductive polymer
Implementation Method 2
A conductive material slurry using a cellulose-based compound and a conductive polymer as dispersants to improve the dispersibility and reduce viscosity
Implementation Method 3
Carbon nanotubes have an sp2 bonding structure. Based on such a structure, carbon nanotubes have received attention as a material with excellent physical properties, such as excellent electrical properties
Data Source
AI summary
A conductive material slurry for a secondary battery electrode, which has low viscosity and low sheet resistance, includes a conductive material and a dispersant that disperses the conductive material. The dispersant includes a cellulose compound and a conductive polymer, and the amount of the conductive material is greater than 0 wt % and equal to or less than 2.5 wt % based on the total weight of the conductive material slurry for a secondary battery electrode.