CNT Paste Moisture Measurement via Solvent Precipitation
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Solution Overview
Problem
Conventional methods for measuring moisture content in carbon nanotube-based pastes, such as Karl-Fischer titration, face challenges due to the high surface area and poor flowability of carbon nanotubes, leading to inaccurate results and interference with reaction reagents, especially when dealing with high viscosity and organic solvent-based systems.
Innovation Solution
The introduction of a second solvent that is miscible with the first solvent in the paste, causing carbon nanotubes to precipitate, allowing for easier measurement of moisture content using Karl Fischer reagents by separating water from the nanotubes and polymeric binders, thereby avoiding interference and improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Karl-Fischer titration is used to measure moisture content in carbon nanotube-based pastes, then the measurement process can be performed, but the high surface area and poor flowability of carbon nanotubes cause inaccurate results and interference with reaction reagents
Solution Approach 1:
The patent extracts carbon nanotubes from the paste sample by adding a non-solvent, causing them to precipitate and separate from the liquid phase. This allows the moisture measurement to be performed on the liquid phase only, eliminating interference from the solid carbon nanotube particles with high surface area and poor flowability.
Solution Approach 2:
The patent introduces a non-solvent as an intermediary substance that mediates between the carbon nanotube paste and the Karl-Fischer reagent. The non-solvent causes carbon nanotubes to aggregate and settle, creating a clear liquid phase that can be easily sampled and measured without solid particle interference.
2Reliability
If carbon nanotubes are used in cathode composition, then enhanced performance is achieved, but conventional composition ratios result in poor adhesion and broken coatings
Solution Approach 1:
The patent changes the compositional parameters of the cathode by introducing a binder component at specific ratios (0.5-5 parts binder per part carbon nanotube). This modifies the physical and chemical properties of the cathode slurry, improving adhesion to the current collector and coating integrity while maintaining the enhanced performance benefits of carbon nanotubes.
Solution Approach 2:
The patent creates a composite cathode structure combining carbon nanotubes with binder materials and active materials. This composite approach leverages the high conductivity of carbon nanotubes while the binder provides structural integrity and adhesion, resulting in a material that exhibits properties superior to the individual components.
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
This method enables precise and repeatable measurement of moisture content in carbon nanotube-based pastes, reducing errors and ensuring accurate control of water levels during electrode preparation for lithium ion batteries, thereby preventing damage and performance issues.
Implementation Method 1
adding a second solvent to the fluid or paste; precipitating the carbon nanotubes from the first and second solvent solution
Implementation Method 2
measuring the water content of the sample by reacting the sample with Karl Fischer reagent
Data Source
AI summary
The present disclosure relates to pastes and methods of making a moisture determination of the paste during manufacture; optionally, the pastes comprise carbon nanotubes. The instant invention provides a simple and repeatable measurement protocol to determine the moisture or water content in paste comprising a non-aqueous solvent and a solid component, optionally, carbon nanotubes, CNT, and subsequently provide a method to monitor and control moisture level during electrode preparation and battery manufacturing.