Fluorinated Ether Electrolyte for Lithium Metal Battery Dendrite Suppression
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Solution Overview
Problem
Nonaqueous electrolyte energy storage devices with metal lithium as the negative active material and ionic liquid electrolytes face a high likelihood of short circuits due to dendrite growth during repeated charge-discharge cycles, especially when the positive electrode has a high capacity density per unit area.
Innovation Solution
Incorporating a fluorinated ether into the nonaqueous electrolyte, which decreases the electrolyte's viscosity and suppresses reductive decomposition, thereby reducing the growth of dendrites and preventing short circuits, while maintaining high coulombic efficiency and energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the capacity density of the positive electrode is increased to enhance energy density, then the energy density of the nonaqueous electrolyte energy storage device is improved, but the likelihood of short circuit due to dendrite growth increases
Solution Approach 1:
The patent changes the chemical composition parameters of the nonaqueous electrolyte by incorporating fluorinated cyclic carbonate and fluorinated chain carbonate components with specific fluorine substitution patterns. This parameter change modifies the electrolyte's interaction with lithium dendrites, suppressing their growth while maintaining high capacity density operation, thereby resolving the contradiction between energy density and short circuit prevention
Solution Approach 2:
The patent uses a composite electrolyte system combining multiple fluorinated carbonate components (cyclic and chain) with specific fluorine substitution ratios. This composite approach creates synergistic effects where the fluorinated structures work together to suppress dendrite growth while enabling high energy density, thus resolving the technical contradiction
2Use of energy by moving object
If metal lithium is used as the negative active material to achieve high energy density, then the energy density is improved, but dendrite growth during charge-discharge cycles causes short circuits
Solution Approach 1:
The patent modifies the electrolyte's chemical parameters by introducing fluorinated cyclic carbonate and fluorinated chain carbonate components with specific molecular structures and fluorine substitution patterns. These parameter changes alter the electrolyte's decomposition behavior at the lithium surface, suppressing dendrite formation while maintaining high energy density performance
Solution Approach 2:
The fluorinated carbonate electrolyte acts as an intermediary layer between the metal lithium negative electrode and the positive electrode. This intermediary electrolyte composition forms protective interface layers that prevent direct harmful interactions and suppress dendrite growth, enabling safe use of high-energy-density metal lithium
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 use of a fluorinated ether in the nonaqueous electrolyte effectively suppresses short circuits and enhances coulombic efficiency and capacity retention in nonaqueous electrolyte energy storage devices with high capacity density positive electrodes, ensuring stable performance during repeated charge-discharge cycles.
Implementation Method 1
Incorporating a fluorinated ether into the nonaqueous electrolyte, which decreases the electrolyte's viscosity
Implementation Method 2
suppresses reductive decomposition, thereby reducing the growth of dendrites
Data Source
AI summary
An aspect of the present invention is a nonaqueous electrolyte energy storage device including: a positive electrode including a positive active material layer of 5 mAh/cm2 or more in capacity density per unit area; a negative electrode including metallic lithium; and a nonaqueous electrolyte including an ionic liquid and a fluorinated ether.