Lithium Metal Battery Separator Air Permeability Control
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Solution Overview
Problem
Nonaqueous electrolyte energy storage devices using metal lithium as a negative active material are prone to short circuits due to dendrite growth, which penetrates the separator and causes electrical contact with the positive electrode during charge-discharge cycles.
Innovation Solution
Incorporating a separator with an air permeability resistance of 150 seconds or less and a nonaqueous electrolyte containing a fluorinated solvent to inhibit dendrite growth and prevent short circuits, while maintaining high capacity retention ratios during charge-discharge cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If metal lithium is used as a negative active material to increase energy density, then the energy density is improved, but dendrite growth occurs during charge-discharge cycles causing short circuits
Solution Approach 1:
A separator with specifically controlled air permeability resistance (150 seconds or less) is introduced as an intermediary component between the negative electrode containing metal lithium and the positive electrode. This separator acts as a mediator that physically blocks dendrite penetration while maintaining ionic conductivity, thereby preventing short circuits without compromising the high energy density provided by metal lithium
Solution Approach 2:
The air permeability resistance of the separator is controlled within a specific range (150 seconds or less) to optimize its ability to suppress dendrite growth. By adjusting this physical parameter of the separator, the system achieves both high energy density from metal lithium and reliable short circuit prevention
2Reliability
If a separator with low air permeability resistance is used to suppress dendrite growth, then short circuit prevention is improved, but ion transport may be hindered
Solution Approach 1:
The air permeability resistance of the separator is optimized within a specific range (150 seconds or less) to achieve the optimal balance between dendrite suppression and ion transport. This parameter control ensures that the separator is sufficiently dense to block dendrites while maintaining adequate porosity and pore structure for efficient lithium ion transport during charge-discharge cycles
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 solution effectively suppresses short circuits and enhances the energy storage device's capacity retention ratio by homogenizing lithium ion concentration and forming a protective film on the negative electrode, ensuring stable operation and increased energy density.
Implementation Method 1
The use of the separator with the low air permeability resistance homogenizes the concentration distribution of lithium ions in the nonaqueous electrolyte in the vicinity of the negative electrode surface, thereby inhibiting the precipitation and growth of dendrites
Implementation Method 2
the film formed on the negative electrode surface from the nonaqueous electrolyte including the fluorinated solvent inhibits precipitation and growth of dendrites
Data Source
AI summary
An aspect of the present invention is a nonaqueous electrolyte energy storage device including a negative electrode containing metal lithium, a nonaqueous electrolyte including a fluorinated solvent, and a separator with an air permeability resistance of 150 seconds or less.