Lithium Ion Battery Separator Chelating Agents
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Solution Overview
Problem
Lithium ion batteries suffer from cumulative capacity reductions and detrimental effects due to the introduction of destructive metal cations, which can lead to negative electrode poisoning and reduced useful life, as these cations migrate through the electrolyte solution and interact with the solvent molecules.
Innovation Solution
Attaching chelating agents such as crown ethers, podands, lariat ethers, calixarenes, or calixcrowns to the microporous polymer separator or electrode components, which selectively complex with and immobilize unwanted metal cations like manganese, cobalt, and iron, preventing their migration and interaction with the negative electrode without affecting lithium ion movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If chelating agents are attached to the microporous polymer separator, then metal cation complexation improves, but lithium ion movement may be affected
Solution Approach 1:
The chelating agents are attached specifically to the microporous polymer separator, creating localized complexation sites only where needed. This local modification allows the separator to selectively complex metal cations while maintaining its fundamental function of allowing lithium ion transport through its microporous structure. The chelating agents are distributed throughout the separator matrix, providing localized complexation capability without blocking the overall ion transport pathways.
Solution Approach 2:
The microporous polymer separator acts as an intermediary between the metal cations in the electrolyte and the chelating agents. The separator provides a structured matrix that holds the chelating agents in fixed positions, allowing them to complex metal cations that pass through the separator while still permitting lithium ions to move freely through the micropores. This intermediary structure enables selective complexation without impeding the primary ion transport function.
2Reliability
If chelating agents are used to trap metal cations, then electrode poisoning is prevented, but battery component complexity increases
Solution Approach 1:
The chelating agents are merged with the microporous polymer separator by attaching them to the separator matrix. This combination integrates the metal cation complexation function directly into the existing separator component, eliminating the need for separate complexation layers or additional battery components. The separator simultaneously performs its primary function of physical separation and ion transport while also providing metal cation complexation through the attached chelating agents.
Solution Approach 2:
The microporous polymer separator is transformed into a multi-functional component that simultaneously performs physical separation of electrodes, facilitates lithium ion transport through its microporous structure, and complexes metal cations through the attached chelating agents. This universalization of the separator's function reduces the need for additional specialized components and simplifies the overall battery structure while providing multiple protective and functional benefits.
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 chelating agents effectively trap and immobilize metal cations, preventing capacity reduction and electrode poisoning, thus maintaining the battery's performance and extending its useful life by ensuring the continued free flow of lithium ions during discharge.
Implementation Method 1
The one or more chelating agents can complex with metal cations but do not strongly complex with lithium ions
Implementation Method 2
The lithium ions are carried through the micropores of the interjacent polymer separator from the negative electrode to the positive electrode by the ionically conductive electrolyte solution
Data Source
AI summary
One embodiment may include a lithium ion battery, wherein one or more chelating agents may be attached to a battery component.