Nonaqueous Electrolyte Scavenger for Fluoride Ion Suppression
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Solution Overview
Problem
Fluorine ions in nonaqueous electrolyte solutions for electricity storage devices can lead to degradation, such as dissolution of transition metals and SEI coating degradation, due to their decomposition and reaction with water and hydrogen fluoride, resulting in increased resistance and performance issues.
Innovation Solution
A nonaqueous electrolyte solution containing a fluorine-containing lithium salt and a scavenger compound represented by the general formula (1), where R1 is an alkyl or phenyl group with halogen substitution and R2, R3, R4 are methyl groups, captures fluorine ions by forming a covalent bond, reducing their presence and thereby suppressing their detrimental effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorine-containing lithium salt is used as electrolyte salt to improve electrochemical properties, then battery performance is enhanced, but fluorine ions remain in the device causing degradation and increased resistance
Solution Approach 1:
The patent introduces a scavenger compound that specifically captures harmful fluorine ions generated from the fluorine-containing lithium salt, converting the harmful byproduct into a beneficial purification mechanism. The scavenger transforms the degradation-causing fluorine ions into stable complexes, thereby maintaining the electrochemical benefits while eliminating the harmful effects.
Solution Approach 2:
The scavenger compound acts as an intermediary substance between the fluorine-containing lithium salt and the electrode components. It mediates by selectively binding fluorine ions, preventing direct contact between fluorine ions and sensitive electrode materials, thus protecting the system while maintaining the desired electrochemical performance.
2Ease of manufacture
If conventional electrolyte composition is used to simplify device structure, then manufacturing is easier, but transition metal dissolution and SEI coating degradation occur
Solution Approach 1:
The patent modifies the electrolyte composition by adding a specific scavenger compound to the conventional electrolyte system. This parameter change (adding the scavenger) maintains the overall simplicity of the device structure while significantly improving electrode stability by preventing transition metal dissolution and SEI coating degradation through fluorine ion capture.
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 scavenger effectively reduces the remaining fluorine ions, preventing degradation of the positive and negative electrodes, thus maintaining battery performance and capacity retention.
Implementation Method 1
captures fluorine ions by forming a covalent bond
Data Source
AI summary
Provided is a technique suppressing remaining of fluorine ions in an electricity storage device including a nonaqueous electrolyte solution containing a fluorine-containing lithium salt. The nonaqueous electrolyte solution contains an electrolyte salt being a fluorine-containing lithium salt, a nonaqueous solvent being carbonate, and a scavenger capturing fluoride ions. The scavenger is a compound represented by the following general formula (1). In the general formula (1), R1 is any of an alkyl group, an alkenyl group, or a phenyl group is equal to or less than 6 carbon atoms and in which at least one hydrogen atom has been substituted with halogen, or is not substituted with halogen; and R2, R3, and R4 are each any one of a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, or a n-butyl group.