Conductive Material Dispersion With Low-Foaming Polymer Dispersant
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Solution Overview
Problem
Existing dispersants for carbon-based conductive materials cause significant foaming and dissolution in electrolytic solutions, leading to increased ion resistance, electron resistance, and reduced battery performance, particularly at low temperatures.
Innovation Solution
A dispersant composition containing a specific polymer with controlled molecular weight and structural units, along with minimized components derived from raw materials, is used to stabilize dispersion and reduce foaming, enhancing conductivity and low-temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional dispersants (polyvinylpyrrolidone, polyvinyl alcohol, or polyacrylonitrile-based polymers) are used to disperse carbon-based conductive materials in aqueous medium, then dispersion stability is improved, but significant foaming occurs and components dissolve in electrolytic solution causing increased ion resistance and electron resistance
Solution Approach 1:
The patent changes the chemical structure parameters of the dispersant by specifying a polymer with 40-100% acrylonitrile units, weight average molecular weight of 5,000-400,000, and limiting low-molecular-weight components to 2% or less. These parameter changes eliminate foaming and prevent dissolution in electrolytic solution while maintaining dispersion stability.
Solution Approach 2:
The patent applies local quality by controlling the molecular weight distribution and compositional uniformity of the dispersant polymer. By ensuring specific structural characteristics (acrylonitrile content, molecular weight range, low oligomer content), the dispersant exhibits localized properties that prevent harmful foaming and dissolution while maintaining effective dispersion function.
2Reliability
If carbon-based conductive materials with large specific surface area (carbon black or carbon nanotubes) are used to achieve high conductivity, then electrical conductivity is improved, but cohesive force increases and hydrophilicity decreases making dispersion difficult
Solution Approach 1:
The patent uses a specifically designed polymer dispersant as an intermediary between the carbon-based conductive material and the aqueous medium. The dispersant's molecular structure (40-100% acrylonitrile units, controlled molecular weight) provides both affinity for the conductive material and compatibility with water, enabling effective dispersion while maintaining high conductivity.
3Ease of operation
If air bubbles are present during dispersion process, then foaming occurs which hinders wetting and chargeability, but using antifoaming agents may cause explosion risk in high pressure homogenizers and device damage
Solution Approach 1:
The patent converts the potential harm of air bubbles by designing a dispersant system that inherently prevents foaming through its specific molecular structure. The controlled polymer composition (acrylonitrile content, molecular weight, low oligomer levels) eliminates the harmful effects of foaming without requiring additional antifoaming agents, thus avoiding explosion risks and device damage.
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 provides a conductive material dispersion with improved electron and ion resistance, favorable rate and cycle properties, and enhanced low-temperature performance in secondary batteries.
Implementation Method 1
a polymer (A), other than a polymer having a low-molecular-weight component (E), and a component (B) other than the polymer and derived from a raw material of the polymer (A)
Implementation Method 2
a dispersant composition containing a specific polymer with controlled molecular weight and structural units, along with minimized components derived from raw materials, is used to stabilize dispersion and reduce foaming
Implementation Method 3
it was found that the components derived from the raw materials of these dispersants (polymer) cause significant foaming and reduces dispersion
Implementation Method 4
a component (B) other than the polymer and derived from a raw material of the polymer (A), wherein a content of the component (B) based on a total mass of the dispersant composition is 1.9 mass% or less
Implementation Method 5
a method of disperse a conductive material in a wet manner, mix it with various materials as necessary, and apply it
Implementation Method 6
If an efficient conductive network can be formed using these dispersants, improvement in initial properties and cycle lifespan can be expected
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.