Lithium Metal Foil Defect Reduction via Gettering
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Solution Overview
Problem
Current battery-grade lithium metal specifications do not account for morphological defects, which affect the uniformity of charge transfer in secondary batteries, leading to performance issues.
Innovation Solution
A lithium metal foil with crystalline defects containing hydrogen, oxygen, or nitrogen is developed, with a method involving molten lithium treatment using a gettering material at 550°C for at least 180 minutes, followed by filtration and extrusion to form a foil with reduced defect density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If battery-grade lithium metal with 99.9% purity is used, then the basic electrochemical function is achieved, but morphological defects remain that adversely affect uniformity in charge transfer
Solution Approach 1:
The patent applies preliminary action by performing defect reduction treatment on lithium metal before it is used as an anode in secondary batteries. The treatment involves heating lithium metal at temperatures between 400-700°C for 1-24 hours to reduce crystalline defects, inclusions, and morphological irregularities before the lithium is incorporated into the battery structure, thereby ensuring uniform charge transfer from the outset
Solution Approach 2:
The patent applies parameter changes by modifying the thermal parameters of lithium metal through controlled heating at specific temperature ranges (400-700°C) for defined durations (1-24 hours). This thermal treatment changes the physical state and microstructure of the lithium, reducing defect density and improving morphological uniformity without altering the chemical composition or purity
2Ease of manufacture
If current battery-grade specifications are maintained, then production cost and complexity are kept low, but performance in secondary batteries is degraded due to unaccounted defects
Solution Approach 1:
The patent applies preliminary action by performing defect reduction treatment on lithium metal before it is used as an anode in secondary batteries. The treatment involves heating lithium metal at temperatures between 400-700°C for 1-24 hours to reduce crystalline defects, inclusions, and morphological irregularities before the lithium is incorporated into the battery structure, thereby ensuring uniform charge transfer from the outset
Solution Approach 2:
The patent applies parameter changes by modifying the thermal parameters of lithium metal through controlled heating at specific temperature ranges (400-700°C) for defined durations (1-24 hours). This thermal treatment changes the physical state and microstructure of the lithium, reducing defect density and improving morphological uniformity without altering the chemical composition or purity
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 approach significantly reduces defect density in lithium metal foils, enhancing the performance and reliability of lithium metal anodes in secondary batteries by minimizing short circuits and self-discharge.
Implementation Method 1
adding a gettering material to the molten lithium metal
Implementation Method 2
holding the molten lithium metal at a temperature of 550° C. for at least 180 minutes
Implementation Method 3
separating the molten lithium from the getter material by filtration
Data Source
AI summary
Commercially-available lithium metal foils have been found to have a high density of crystalline defects. When such foils are used as the anode in a secondary lithium metal battery cell, repeated cycling may lead to the formation of lithium shunts near the crystalline defects, which can cause shorting. Methods described herein may be used to reduce the density of crystalline defects in lithium metal foils. Such lithium metal can be used as the anode in lithium battery cells.