LiF Coated Anode for Uniform SEI Formation
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Solution Overview
Problem
Lithium ion secondary batteries using carbon materials as anodes face performance deterioration and shortened life cycles due to irregular formation of LiF on the anode surface caused by side reactions during charging and discharging.
Innovation Solution
A LiF-based coating layer with a thickness of 0.05 to 1 μm is formed on the anode surface by immersing the anode in a LiPF6 dissolved carbonate-based organic solvent and applying a voltage or current under moisture conditions, ensuring a relatively uniform LiF layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a coating layer is formed on the anode surface to prevent irregular LiF formation, then the battery life cycle is improved, but the initial battery performance is deteriorated
Solution Approach 1:
The patent applies parameter changes by precisely controlling the coating layer thickness within 0.05 to 1 μm and controlling the moisture content in the electrolyte solution to be 50 to 2000 ppm. These parameter optimizations allow the coating layer to prevent irregular LiF formation and extend battery life while minimizing negative impact on initial performance
Solution Approach 2:
The patent applies local quality by forming a coating layer with specific local properties (thickness of 0.05 to 1 μm, containing LiF-based particles) on the anode surface. This localized modification addresses the irregular LiF formation problem at the surface level without affecting the bulk properties of the anode, thereby extending battery life while maintaining acceptable initial performance
2Productivity
If LiF is formed on the anode surface during charging and discharging, then the battery operates, but irregular LiF formation deteriorates battery performance and shortens life cycle
Solution Approach 1:
The patent applies preliminary action by pre-forming a coating layer containing LiF-based particles on the anode surface before battery operation. This pre-formed coating layer serves as a template that guides subsequent LiF formation during charging/discharging, ensuring uniform growth rather than irregular deposition, thereby extending battery life cycle
Solution Approach 2:
The patent converts the harmful effect of LiF formation (which normally deteriorates performance and shortens life cycle) into a beneficial effect. By pre-forming a controlled coating layer with LiF-based particles, the patent transforms the problematic side reaction product into a useful component that promotes uniform LiF formation and extends battery life
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 uniform LiF coating layer slows down battery performance degradation, maintaining battery performance for a longer term and extending the life cycle while controlling high-temperature degradation.
Implementation Method 1
When lithium ions are intercalated or disintercalated at the cathode and the anode, oxidation and reduction reactions are made to generate electric energy
Implementation Method 2
LiF generated by side reaction of LiPF6 used as an electrolyte is irregularly formed on an anode surface
Implementation Method 3
When lithium ions are intercalated or disintercalated at the cathode and the anode, oxidation and reduction reactions are made to generate electric energy
Implementation Method 4
When lithium ions are intercalated or disintercalated at the cathode and the anode, oxidation and reduction reactions are made to generate electric energy
Data Source
AI summary
An anode for a lithium ion secondary battery includes an anode, and a LiF-based coating layer formed with LiF-based particles on a surface of the anode. The LiF-based coating layer has a thickness of 0.05 to 1 μm. The anode allows the LiF-based coating layer created by side reaction of LiPF6 during a battery charging/discharging process to be relatively uniformly formed on the anode surface, thereby elongating the life cycle of a lithium ion secondary battery.