Lithium-Exchanged Zeolite Particles via Ammonium-Mediated Ion Exchange
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Solution Overview
Problem
Existing methods face challenges in producing lithium ion-exchanged zeolite particles, particularly in achieving effective ion exchange between lithium ions with larger hydrated radii and cations with smaller hydrated radii like sodium and potassium, which affects the performance and longevity of lithium-ion batteries.
Innovation Solution
A method involving the combination of precursor zeolite particles with (NH4)3PO4 to form intermediate zeolite particles, followed by the addition of a lithium salt, such as LiOH, to produce lithium ion-exchanged zeolite particles with Li+ and NH4+ cations, which can be used in the framework of various zeolite materials like NAT and ZSM-5, facilitating the removal of trace water and other contaminants from the electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ion exchange methods are used to exchange lithium ions with larger hydrated radii and cations with smaller hydrated radii, then the ion exchange efficiency is poor, but the process complexity increases when alternative methods are attempted
Solution Approach 1:
The patent uses ammonium phosphate ((NH4)3PO4) as an intermediary substance to facilitate the ion exchange process. The ammonium ions first exchange with the smaller cations (Na+, K+) in the zeolite, creating intermediate zeolite particles with ammonium cations. Then lithium ions exchange with the ammonium ions, achieving effective lithium ion incorporation. This two-step intermediary process overcomes the difficulty of direct ion exchange between lithium ions and smaller cations.
2Reliability
If lithium ion-exchanged zeolite particles are used to remove contaminants from electrolyte, then battery cycle performance and life are improved, but the manufacturing difficulty of the zeolite particles increases
Solution Approach 1:
The patent performs preliminary ion exchange by first exchanging the zeolite cations with ammonium ions from ammonium phosphate before the lithium ion exchange step. This preliminary action of converting to ammonium-form zeolite creates optimal conditions for subsequent lithium ion exchange, ensuring high lithium ion content and proper distribution in the final product, which directly improves battery performance.
Solution Approach 2:
Ammonium phosphate serves as an intermediary reagent that enables controlled and complete ion exchange. The ammonium ions act as a mediator that facilitates the replacement of smaller cations with lithium ions, ensuring thorough exchange and high lithium ion content in the final zeolite particles, thereby improving manufacturing reliability.
3Object-affected harmful factors
If lithium ions with larger hydrated radii are exchanged with cations with smaller hydrated radii, then contaminant removal capability is enhanced, but ion exchange effectiveness decreases
Solution Approach 1:
The patent introduces ammonium ions as an intermediary that bridges the size difference between small cations (Na+, K+) and lithium ions. The ammonium ions first occupy the zeolite exchange sites, then facilitate lithium ion incorporation through a second exchange step, achieving both high contaminant removal capability and effective lithium ion exchange.
Solution Approach 2:
The ion exchange process is segmented into two distinct steps: first exchanging with ammonium ions, then exchanging with lithium ions. This segmentation allows each step to be optimized independently, ensuring both complete removal of smaller cations and effective incorporation of lithium ions, thereby resolving the contradiction between contaminant removal and exchange effectiveness.
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 resulting lithium ion-exchanged zeolite particles improve the cycle performance and life of lithium-ion batteries by effectively removing contaminants without inhibiting lithium ion transport, thereby enhancing the battery's stability and efficiency.
Implementation Method 1
it can be difficult to produce such lithium ion-exchange zeolite particles, in particular, it may be difficult to achieve an exchange between lithium ions having a larger hydrated radius and cations with a smaller hydrated radius, such as sodium and potassium cations
Implementation Method 2
Lithium ion-exchanged zeolite particles, for example, present in a coating layer on a porous separator, can actively remove trace water, hydrogen ions, hydrofluoric acid, dissociated transition metal ions (e.g., Mn2+, Fe2+, and Fe3+ ions), polysulfides, and other target compounds from the liquid electrolyte
Data Source
AI summary
Lithium ion-exchanged zeolite particles and methods of making such lithium ion-exchanged zeolite particles are provided herein. The method includes combining precursor zeolite particles with (NH4)3PO4 to form a first mixture including intermediate zeolite particles including NH4<sup2>+</sup2> cations. The method further includes adding a lithium salt to the first mixture to form the lithium ion-exchanged zeolite particles, or separating the intermediate zeolite particle from the first mixture and combining the intermediate zeolite particles with the lithium salt to form the lithium ion-exchanged zeolite particles.