Negative Electrode Slurry Clay Thickening
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Solution Overview
Problem
The existing negative electrode slurry compositions for lithium secondary batteries face challenges with storage stability and dispersion due to sedimentation of solid particles, particularly graphite-based active materials, which affects the uniformity of the coating layer and efficiency in the manufacturing process.
Innovation Solution
A negative electrode slurry composition incorporating clay particles with a plate-type structure and an average particle diameter of 10 nm to 2 μm, carboxymethylcellulose (CMC), and a negative electrode active material, with a weight ratio of CMC to clay particles ranging from 9.5:0.5 to 4:6, improves dispersion and storage stability by enhancing the thickening effect and preventing sedimentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the solid content in negative electrode slurry composition is increased to improve manufacturing efficiency and productivity, then the productivity and efficiency of the manufacturing process is improved, but the storage stability deteriorates due to sedimentation of solid particles
Solution Approach 1:
The patent introduces a dispersant as an intermediary substance to mediate between the solid particles (graphite-based active material) and the aqueous solvent. The dispersant prevents sedimentation of solid particles in high solid content slurry while maintaining good dispersion, thereby resolving the contradiction between high productivity (high solid content) and storage stability (prevention of sedimentation).
Solution Approach 2:
The patent creates a composite slurry system combining graphite-based active material, binder, dispersant, and aqueous solvent in specific proportions. This composite formulation with solid content of 5 wt% to 70 wt% achieves both high productivity and storage stability through the synergistic interaction of components, particularly the dispersant that maintains particle suspension.
2Stability of the object's composition
If a thickener is added to improve dispersion of graphite-based active material, then the dispersion is improved, but the content of other components in the slurry decreases, deteriorating battery performance
Solution Approach 1:
The patent changes the parameter of solid content to a specific range (5 wt% to 70 wt%) and optimizes the proportion of dispersant relative to solid content (0.1 wt% to 10 wt% based on solid content). This parameter optimization achieves good dispersion without excessive thickener addition, maintaining adequate content of other components for battery performance.
3Use of energy by moving object
If graphite-based active material is used in negative electrode slurry, then the energy density and operating potential are improved, but the storage stability decreases due to sedimentation of the hydrophobic graphite particles
Solution Approach 1:
The dispersant acts as an intermediary that bridges the hydrophobic graphite particles and the aqueous solvent. It adsorbs onto the graphite particle surfaces and provides steric or electrostatic stabilization, preventing sedimentation while maintaining the high energy density benefits of graphite-based active material.
Solution Approach 2:
The patent optimizes the concentration of dispersant within specific ranges (0.1 wt% to 10 wt% based on solid content) to achieve adequate dispersion and storage stability. This controlled parameter adjustment ensures graphite particles remain suspended without excessive thickener that would compromise battery performance.
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 proposed solution achieves improved storage stability and dispersion of the negative electrode active material, leading to a higher solid content and reduced non-uniformity, thereby enhancing the manufacturing efficiency and performance of lithium secondary batteries.
Implementation Method 1
improves dispersion and storage stability by enhancing the thickening effect and preventing sedimentation
Implementation Method 2
the graphite-based active material is settled in the slurry over time, and thus, may cause the storage stability problem of the slurry
Data Source
AI summary
A negative electrode slurry composition including (1) clay particles having, a plate-type structure and an average particle diameter (D50) of 10 nm to 2 μm, (2) carboxymethylcellulose (CMC), (3) a negative electrode active material, and (4) an aqueous solvent, wherein a weight ratio of the carboxymethylcellulose and the clay particles is 9.5:0.5 to 4:6. The negative electrode slurry composition is capable of solving problems due to the deterioration of storage stability and dispersibility of solids in a negative electrode slurry composition having a high solid content.