Lithium-Exchanged Zeolite Dehydration for Battery Electrolytes
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Solution Overview
Problem
Conventional methods for dehydrating nonaqueous electrolytic solutions using zeolites face challenges such as sodium elution and complex processes, particularly when attempting to achieve water levels below 50 ppm, which is crucial for lithium batteries and other applications.
Innovation Solution
A zeolite with a lithium ion-exchange ratio of 97.5 to 99.5 mol % is developed, specifically ion-exchanging cations to prevent sodium elution, using zeolites like A-type, chabazite, ferrierite, or ZSM-5, and forming shaped bodies with high zeolite content to ensure efficient dehydration without contaminating the solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If azeotropic dehydration is used to remove water from nonaqueous electrolytic solution, then water removal is achieved, but water amount cannot be reduced to 50 ppm or less
Solution Approach 1:
The patent employs zeolite, a porous material with specific pore structures, to adsorb water molecules from the nonaqueous electrolytic solution. The porous structure provides high surface area and selective adsorption sites that enable deep dehydration to achieve water levels of 50 ppm or less, overcoming the limitation of azeotropic dehydration methods.
2Quantity of substance
If conventional zeolite is used for dehydration, then water is removed, but cation elution contaminates the electrolytic solution
Solution Approach 1:
The patent applies preliminary ion exchange treatment to replace the original cations in the zeolite with lithium ions before using the zeolite for dehydration. This preliminary action prevents subsequent cation elution into the electrolytic solution, eliminating contamination while maintaining the water removal capability of the zeolite structure.
Solution Approach 2:
The patent changes the cationic composition parameter of the zeolite by performing ion exchange with lithium ions. This parameter change transforms the zeolite from a state that would cause contamination to a state that is compatible with the electrolytic solution, allowing deep dehydration without introducing harmful cation elution.
3Object-generated harmful factors
If complete ion exchange with lithium is performed to prevent sodium elution, then contamination is prevented, but cost increases due to expensive lithium
Solution Approach 1:
The patent applies partial ion exchange, replacing only a portion of the original cations with lithium ions rather than achieving complete exchange. This partial action is sufficient to prevent harmful sodium elution into the electrolytic solution while reducing the amount of expensive lithium required, thereby lowering manufacturing costs compared to complete ion exchange.
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 zeolite effectively removes water and free acids from nonaqueous electrolytic solutions without eluting sodium or other contaminants, simplifying the dehydration process and maintaining solution purity, thereby enhancing the efficiency and reliability of lithium battery electrolytes.
Implementation Method 1
a method of removing water in the nonaqueous electrolytic solution by utilizing water adsorption capacity of a zeolite
Implementation Method 2
an ion-exchangeable cation is present in the zeolite, and lithium ion in the nonaqueous electrolytic solution and the cation in the zeolite cause an ion exchange reaction during the dehydration treatment
Data Source
AI summary
An object of the present invention is to provide a zeolite enabling a dehydration treatment of a nonaqueous electrolytic solution without causing a problem of elution of sodium from the zeolite at the time of dehydrating a nonaqueous electrolytic solution for a lithium battery by using a zeolite. The present invention relates to a zeolite, wherein from 97.5 to 99.5 mol % of the ion-exchangeable cation is ion-exchanged with lithium, and when this zeolite is used, a nonaqueous electrolytic solution can be dehydrated while keeping the elution of a cation impurity such as sodium down to 50 ppm or less. As for the zeolite species, at least one or more zeolites selected from the group consisting of A-type, chabazite, ferrierite, ZSM-5 and clinoptilolite can be used.