Zeolite Molecular Sieve Dehydration for Lithium Battery Solvents
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Solution Overview
Problem
Current methods for producing dehydrated liquid mixtures for lithium ion batteries are inefficient in reducing water and isopropyl alcohol content, leading to contamination and performance issues due to ion exchange reactions and contamination from binders used in zeolite molecular sieves, and require complex processes involving distillation and adsorption.
Innovation Solution
A method involving cleaning the production equipment with isopropyl alcohol, followed by evaporation and purging to remove contaminants, and then using a zeolite molecular sieve to simultaneously reduce both water and isopropyl alcohol content in the liquid starting mixture, which includes organic carbonates and acetic or butyric acid esters, to achieve a dehydrated solvent for conducting salts with low water and isopropyl alcohol levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional zeolite molecular sieves with ion-exchangeable cations are used for dehydration, then water removal is effective, but ion exchange reactions occur contaminating the electrolyte mixture
Solution Approach 1:
The patent applies local quality by modifying the zeolite molecular sieve to have lithium ions specifically positioned in the exchange sites, creating a localized property that prevents ion exchange with lithium ions in the electrolyte while maintaining water adsorption capability. This resolves the contradiction by making the zeolite selectively inert to lithium ions while still effective for water removal.
Solution Approach 2:
The patent changes the chemical parameter of the zeolite by replacing conventional cations (such as sodium or calcium) with lithium ions through ion exchange treatment. This parameter change transforms the zeolite from one that would react with lithium in the electrolyte to one that is chemically compatible, eliminating the harmful ion exchange reaction while preserving dehydration function.
2Strength
If binder materials are added to zeolite molecular sieves to improve mechanical stability, then structural integrity is enhanced, but contamination of the electrolyte mixture occurs
Solution Approach 1:
The patent employs disposable binderless zeolite molecular sieves that are used once for dehydration and then discarded or regenerated. This eliminates the need for durable binder materials that would contaminate the electrolyte, resolving the contradiction by sacrificing mechanical permanence to achieve chemical purity. The zeolite is contained in a housing that allows easy removal and replacement.
Solution Approach 2:
The patent extracts and removes the binder component from the zeolite molecular sieve assembly, creating a binderless design. This extraction eliminates the source of contamination while the zeolite is contained in a housing structure that provides mechanical support without introducing harmful materials into the electrolyte.
3Object-affected harmful factors
If separate drying of solvent mixture and conducting salt is performed, then ion exchange contamination is avoided, but process complexity increases
Solution Approach 1:
The patent creates a universal dehydration solution by treating the zeolite molecular sieve with lithium ions, enabling it to perform water removal in the presence of lithium conducting salts without causing ion exchange contamination. This single modified zeolite handles both functions (dehydration and compatibility with lithium salts) that previously required separate processing steps, thereby simplifying the overall process.
4Ease of manufacture
If initial water content in organic carbonates is high (100-1000 ppm), then commercial availability is improved, but battery performance is reduced
Solution Approach 1:
The patent applies preliminary action by implementing a dehydration step using lithium-ion exchanged zeolite molecular sieves in the production process. This preliminary treatment removes water from the organic carbonate solvent to achieve the required low water content (<50 ppm) for battery performance, while maintaining the benefit of using commercially available solvents with higher initial water content.
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 effectively reduces water and isopropyl alcohol content to below 20 ppm and 5 ppm respectively, minimizing contamination and ion exchange issues, while simplifying the process and improving the stability of the dehydrated liquid mixture for use in lithium ion batteries.
Implementation Method 1
both the isopropyl alcohol content in the mixture and the water content in the mixture is reduced by interaction with a zeolite molecular sieve
Implementation Method 2
removing contaminating substances (e.g. liquid substances) from the interior of the production equipment after cleaning with isopropyl alcohol
Data Source
AI summary
The present invention relates in a first aspect to a method for producing in the interior of a production equipment a dehydrated liquid mixture for use as a solvent for a conducting salt (e.g. LiPF6) wherein after cleaning the equipment with isopropyl alcohol and providing or preparing a liquid starting mixture in said interior of the production equipment both the isopropyl alcohol content in the mixture and the water content in the mixture is reduced by interaction with a zeolite molecular sieve.