Aqueous Graphite Electrode Dispersion With Low Viscosity
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Solution Overview
Problem
Existing graphite-based electrode compositions for lithium ion batteries suffer from issues such as high viscosity, non-uniform dispersion of electroconductive agents and active materials, leading to increased resistance, self-discharge, and reduced cycle life, which affect the performance and efficiency of the battery.
Innovation Solution
A graphite dispersion for battery electrodes comprising graphite particles with an average size of 5 to 50 µm, a dispersing agent like polyvinylpyrrolidone or carboxymethyl cellulose, and water, which allows for homogeneous distribution of electroconductive agents and active materials, maintaining low viscosity and reducing electrode resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flaked graphite is used as electrode material without reactive functional groups, then electrochemical performance is improved, but dispersion uniformity deteriorates and viscosity increases
Solution Approach 1:
The patent introduces a dispersing agent as an intermediary substance between flaked graphite and solvent. The dispersing agent contains specific functional groups that interact with graphite surfaces, enabling uniform dispersion without requiring the graphite itself to have reactive functional groups. This resolves the contradiction by mediating the interaction between graphite and solvent through a third substance.
Solution Approach 2:
The patent changes the chemical composition parameters of the dispersion system by introducing a dispersing agent with specific functional groups. This parameter change allows the system to achieve both good dispersion uniformity and maintained electrochemical performance, as the dispersing agent's functional groups provide the necessary interfacial interactions without altering the graphite's electrochemical properties.
2Stability of the object's composition
If dispersing agent is added to flaked graphite composition, then dispersion uniformity improves, but viscosity increases significantly
Solution Approach 1:
The patent optimizes the molecular weight and chemical structure parameters of the dispersing agent to achieve a balance between dispersion capability and viscosity control. By selecting dispersing agents with specific molecular characteristics, the patent reduces viscosity increase while maintaining dispersion uniformity.
Solution Approach 2:
The patent uses a controlled, partial amount of dispersing agent rather than excessive quantities. This partial action approach achieves sufficient dispersion uniformity while minimizing the viscosity-increasing effect, avoiding the need for excessive dispersing agent that would cause significant viscosity increase.
3Quantity of substance
If highly viscous paste composition is used, then material loading is high, but uniform distribution of electroconductive agent and active material deteriorates
Solution Approach 1:
The patent changes the rheological parameters of the composition by introducing a dispersing agent that reduces internal friction and improves flow characteristics. This parameter change allows the composition to maintain high material loading while achieving uniform distribution during application, as the improved fluidity enables better mixing and distribution.
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 uniform distribution of electroconductive agents and active materials, enhancing electrical conductivity and stability while maintaining high cycle and self-discharge characteristics, suitable for producing high-efficiency lithium ion batteries.
Implementation Method 1
a dispersing agent, and water... flaked graphite and the like is homogeneously dispersed
Data Source
AI summary
Provided is a graphite dispersion for a battery electrode, which is suitable for production of a battery electrode of a lithium ion battery or the like. The graphite dispersion for a battery electrode of the present disclosure includes at least graphite particles having an average particle size of 5 to 50 µm, a dispersing agent, and water.