Graphene Organic Solvent Dispersion Water Content Control
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Solution Overview
Problem
Existing methods for producing graphene/organic solvent dispersion liquids for lithium ion batteries face challenges in achieving stable dispersion and preventing water electrolysis, due to inadequate removal of bound water and agglomeration issues.
Innovation Solution
A method involving a reduction step, organic solvent mixing, strong stirring, and water removal steps is employed to control the bound water content on graphene, ensuring a stable dispersion with a specific water fraction range and using a surface treatment agent to enhance dispersibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If graphene is produced by heating and expansion to remove water, then water content is reduced, but functional groups and surface water are removed making dispersion in organic solvent impossible
Solution Approach 1:
The patent controls the water content parameter within a specific range (0.03 to 0.3 mass%) rather than completely removing it. This parameter optimization allows the graphene to maintain both low water content and sufficient surface functionality for organic solvent dispersion, resolving the contradiction between water removal and dispersibility.
2Ease of manufacture
If graphene is produced by chemical reduction and freeze-drying, then dispersibility is improved, but large quantity of bound water remains causing battery degradation
Solution Approach 1:
The patent optimizes the bound water content parameter to a specific range (0.03 to 0.3 mass%) through controlled reduction and drying processes. This prevents excessive bound water that would cause battery degradation while maintaining adequate dispersibility, resolving the contradiction between these two properties.
3Ease of manufacture
If aqueous graphene dispersion is mixed with organic solvent without thorough water removal, then processing is simplified, but water remains causing electrolysis and battery degradation
Solution Approach 1:
The patent sets a threshold parameter for water content (0.03 to 0.3 mass%) that balances process simplicity with preventing water electrolysis. By controlling water content to this range rather than requiring complete removal, the patent maintains manufacturing simplicity while eliminating harmful electrolysis effects.
4Productivity
If graphene is produced by oxidization-reduction method for large-scale synthesis, then productivity is improved, but agglomeration occurs reducing dispersibility
Solution Approach 1:
The patent optimizes multiple parameters including water content (0.03 to 0.3 mass%), organic solvent selection, and processing conditions to prevent agglomeration during large-scale oxidization-reduction synthesis. These parameter controls enable both high productivity and good dispersibility to be achieved simultaneously.
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 method results in a graphene/organic solvent dispersion liquid with improved dispersibility and conductivity, enabling the formation of high-performance lithium ion battery electrodes with enhanced electrical and ion conductivity.
Implementation Method 1
converting it into graphene through reduction reaction
Implementation Method 2
a water removal step for removing at least part of the water from the intermediate dispersion liquid by a combination of the addition of an organic solvent and suction filtration or by distillation
Data Source
AI summary
A graphene/organic solvent dispersion liquid is in a stably dispersed state and also unlikely to cause electrolysis of water. A graphene/organic solvent dispersion liquid is also provided including graphene dispersed in an organic solvent and having a value of (W2−W1)/G in the range of 0.005 or more and 0.05 or less, wherein W1 and W2 are the water fractions measured at 130° C. and 250° C., respectively, by the Karl Fischer's method and G is the solid fraction of the graphene.