Dual-Dispersant Conductive Dispersion for High-Solid Electrodes
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Solution Overview
Problem
Conductive material dispersions using existing dispersants face challenges with high viscosity, limiting the increase in conductive material content and electrical conductivity, and suffer from storage stability issues due to gelation when trying to lower molecular weight for reduced viscosity.
Innovation Solution
A conductive material dispersion with a nitrile-based copolymer as the main dispersant and a copolymer including an oxyalkylene unit and styrene/alkylene units as the auxiliary dispersant, which reduces viscosity and enhances dispersibility, allowing for higher solid content and improved electrode manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the content of conductive material in the dispersion is increased to improve electrical conductivity, then the electrical conductivity is improved, but the viscosity increases rapidly
Solution Approach 1:
The patent introduces a specific dispersant as an intermediary substance to mediate between conductive material particles. This dispersant forms a protective layer around the conductive material, preventing direct aggregation and reducing inter-particle friction, thereby maintaining low viscosity even at high conductive material content (up to 30 wt% or higher).
Solution Approach 2:
The patent optimizes molecular weight parameters of the dispersant to achieve the desired balance. By selecting a dispersant with specific molecular weight range, the system achieves sufficient steric hindrance to prevent aggregation while maintaining adequate chain flexibility to reduce viscosity, enabling high electrical conductivity without excessive viscosity increase.
2Ease of operation
If the weight average molecular weight of the dispersant is lowered to reduce viscosity, then the viscosity is reduced, but storage stability degrades due to gelation
Solution Approach 1:
The patent precisely controls the molecular weight parameter of the dispersant within a specific range. This optimized molecular weight provides the right balance between chain length (for steric stabilization) and chain flexibility (for viscosity reduction), preventing both excessive viscosity and gelation while maintaining storage stability.
Solution Approach 2:
The patent employs a composite dispersant system or a dispersant with composite molecular structure combining different functional segments. This composite approach provides both the steric hindrance needed for stability and the flexibility needed for low viscosity, resolving the contradiction between storage stability and ease of operation.
3Productivity
If the solid content of the conductive material dispersion is increased to improve productivity and drying efficiency, then productivity and drying efficiency are improved, but the viscosity increases
Solution Approach 1:
The dispersant acts as a mediator that enables high solid content formulations by preventing particle aggregation and maintaining fluidity. This allows the system to achieve high productivity and drying efficiency through increased solid content while the dispersant keeps viscosity at acceptable levels for processing.
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 achieves lower viscosity, enabling increased conductive material content, improved electrode drying efficiency, adhesion force, and productivity while maintaining storage stability.
Implementation Method 1
a copolymer including an oxyalkylene unit and at least one selected from the group consisting of a styrene unit and an alkylene unit as an auxiliary dispersant
Data Source
AI summary
A conductive material dispersion includes a carbon-based conductive material, a main dispersant, an auxiliary dispersant, and a dispersion medium, wherein the main dispersant is a nitrile-based copolymer and the auxiliary dispersant is a copolymer including an oxyalkylene unit and at least one selected from the group consisting of a styrene unit and an alkylene unit.