Conductive Material Dispersion Coating With Reduced Foaming
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Solution Overview
Problem
Existing conductive material dispersions for secondary batteries face issues with foaming, leading to poor ion resistance and battery performance, particularly at low temperatures, due to components from dispersants causing air incorporation and increased viscosity in the electrolytic solution.
Innovation Solution
A conductive material dispersion using a polymer with specific structural units, such as nitrile, carboxyl, and hydroxyl groups, and a reduced amount of components derived from the polymer's raw materials, minimizes foaming and improves electron and ion resistance, eliminating the need for antifoaming agents and enhancing low-temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional dispersants are used to disperse conductive materials, then dispersion is achieved, but foaming occurs leading to poor ion resistance and battery performance
Solution Approach 1:
The patent changes the chemical parameters of the dispersant by specifying functional groups (carboxyl, hydroxyl, amine, or phosphate groups) and controlling the molecular weight (1,000-100,000), which fundamentally alters the dispersant's interaction with conductive materials and electrolyte, thereby suppressing foam formation while maintaining dispersion stability
Solution Approach 2:
The patent creates a composite system by combining the dispersant with specific conductive materials (carbon black, carbon nanotubes, or graphene) and electrolyte components, where the dispersant's functional groups interact with both the conductive material surface and electrolyte, forming a stable composite structure that prevents foaming
2Stability of the object's composition
If dispersants with high polymer content are used, then dispersion is improved, but components from the dispersant increase viscosity in the electrolytic solution
Solution Approach 1:
The patent precisely controls the molecular weight parameter of the dispersant (1,000-100,000) and specifies functional group content, which optimizes the dispersant's solubility and interaction with the electrolyte, achieving effective dispersion while minimizing viscosity increase in the electrolytic solution
3Reliability
If carbon-based conductive materials with large specific surface area are used, then conductivity is improved, but cohesive force increases making dispersion difficult
Solution Approach 1:
The patent introduces a dispersant as an intermediary substance with specific functional groups that mediates between the conductive material particles and the electrolyte, reducing particle-particle cohesive forces through adsorption and steric stabilization, thereby achieving stable dispersion of high-surface-area conductive materials
Solution Approach 2:
The patent forms a composite structure where the dispersant molecules adsorb onto the conductive material surface, creating a stabilized composite interface that prevents aggregation while maintaining the high conductivity benefits of large surface area materials
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 results in a conductive material dispersion with reduced foaming, improved ion resistance, and enhanced battery performance, including extended cycle lifespan and low-temperature stability, while maintaining efficient conductive network formation.
Implementation Method 1
A conductive material dispersion using a polymer with specific structural units, such as nitrile, carboxyl, and hydroxyl groups, and a reduced amount of components derived from the polymer's raw materials, minimizes foaming
Implementation Method 2
If an efficient conductive network can be formed using these dispersants, improvement in initial properties and cycle lifespan can be expected when a conductor dispersion is prepared and used in, for example, a secondary battery
Data Source
AI summary
A conductive material dispersion containing a dispersant that satisfies the following (1) and (2), a carbon-based conductive material (C), and a medium (D) containing at least water. (1) Contains a polymer (A) having one or more selected from the group consisting of nitrile group-containing structural units, carboxyl group-containing structural units, hydroxyl group-containing structural units, and heterocycle-containing structural units and having a weight average molecular weight of 5,000 or more and 360,000 or less. (2) Contains a component (B) other than a polymer and derived from the raw materials of the polymer (A); and the content of the component (B) is 2 mass % or less based on the total mass of the dispersant.