LiF-Coated Lithium Alloy Electrode for Dendrite Suppression
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Solution Overview
Problem
Lithium-based secondary batteries face issues such as dendrite formation, internal short circuits, and reduced life characteristics due to volume changes and surface oxide film destruction, which can lead to safety hazards and performance degradation.
Innovation Solution
A method of manufacturing a lithium alloy electrode by melting lithium and a metal fluoride powder to form lithium fluoride (LiF) on the surface, suppressing dendrite growth and enhancing conductivity, involving steps of producing a first melt, stirring with the metal fluoride powder to create a second melt, and forming a lithium alloy electrode through extrusion and rolling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a lithium electrode is used to improve energy density, then energy density is improved, but dendrite formation and internal short circuits occur leading to safety issues and reduced battery life
Solution Approach 1:
A lithium alloy electrode comprising lithium and magnesium is introduced as an intermediary solution between pure lithium electrodes and conventional electrodes. The magnesium component acts as a mediator that suppresses dendrite formation while maintaining high energy density, thus resolving the contradiction between energy density improvement and safety/reliability concerns
Solution Approach 2:
The invention uses a composite lithium-magnesium alloy electrode material that combines the high energy density advantage of lithium with the structural stability and dendrite-suppressing properties of magnesium. This composite approach allows simultaneous achievement of high energy density and improved battery safety
2Duration of action of stationary object
If a lithium alloy electrode is used to improve life characteristics through surface oxide film formation, then life characteristics are improved, but volume change and surface oxide film destruction occur during continuous charging and discharging
Solution Approach 1:
The invention optimizes the magnesium content parameter in the lithium alloy electrode to a specific range (0.1-10 wt%) to achieve the right balance between forming a protective surface oxide film and maintaining volume stability during cycling. This parameter optimization allows the surface film to protect the electrode while minimizing volume expansion issues
3Reliability
If metal fluoride powder is added to lithium melt to form LiF on the surface, then dendrite growth is suppressed and conductivity is enhanced, but manufacturing process complexity increases
Solution Approach 1:
The metal fluoride powder is added to the lithium melt during the electrode manufacturing process itself, rather than requiring separate surface treatment steps after electrode fabrication. This preliminary incorporation of fluoride during manufacturing simplifies the overall process while achieving the desired LiF surface formation for dendrite suppression and conductivity enhancement
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 lithium alloy electrode with LiF surface protection improves battery performance and life characteristics by preventing dendrite growth and enhancing stability, resulting in improved capacity retention.
Implementation Method 1
melting lithium (Li) at a first temperature to produce a first melt; stirring a metal fluoride powder together with the first melt at a second temperature to produce a second melt
Implementation Method 2
stirring a metal fluoride powder together with the first melt at a second temperature to produce a second melt
Data Source
AI summary
A method of manufacturing an electrode for secondary battery is provided. The method includes melting lithium at a first temperature to produce a first melt; stirring a metal fluoride powder together with the first melt at a second temperature to produce a second melt; and producing a lithium alloy electrode with the second melt, wherein the lithium alloy electrode includes lithium fluoride.