Nonaqueous Electrolyte with Fluoride Scavenger for Battery Stability
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Solution Overview
Problem
Nonaqueous electrolyte solutions in electricity storage devices face issues with fluorine ion retention, leading to degradation of battery performance due to reactions with electrodes and solvents, causing increased resistance and material dissolution.
Innovation Solution
Incorporating a scavenger compound represented by the general formula (1) into the nonaqueous electrolyte solution, which captures fluorine ions by forming a covalent bond with silicon atoms, thereby suppressing their retention and reducing steric hindrance and enhancing electron-withdrawing effects to facilitate desorption of ester groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorine-containing lithium salt is used as electrolyte salt to improve ionic conductivity and electrochemical performance, then battery performance is enhanced, but fluorine ions remain in the electrolyte solution causing electrode degradation and increased resistance
Solution Approach 1:
A scavenger compound containing silicon atoms is introduced as an intermediary substance that selectively captures fluorine ions from the electrolyte solution. The scavenger acts as a mediator between the harmful fluorine ions and the battery components, forming stable complexes that prevent fluorine ion deposition on electrodes while maintaining electrolyte functionality.
Solution Approach 2:
The harmful fluorine ions that would otherwise degrade electrodes are converted into beneficial complexes with the scavenger compound. The fluorine-silicon bonding in the scavenger complex stabilizes the fluorine ions, transforming them from harmful contaminants into stable, non-reactive species that can remain in the electrolyte without causing damage.
2Stability of the object's composition
If conventional electrolyte additives are used to form protective films on electrodes, then electrode stability is improved, but fluorine ions still decompose these films and cause material dissolution
Solution Approach 1:
The scavenger compound performs preliminary action by capturing fluorine ions before they can reach and attack the electrode surfaces. This preventive mechanism removes the harmful fluorine ions from the electrolyte solution in advance, protecting the electrodes and their protective films from fluorine-induced degradation and dissolution.
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 reduces fluorine ion retention, preventing electrode degradation and maintaining battery performance by capturing and stabilizing fluorine ions within the electrolyte solution, thus enhancing the capacity retention rate and suppressing defects in the electricity storage device.
Implementation Method 1
captures fluorine ions by forming a covalent bond with silicon atoms
Implementation Method 2
a scavenger which captures fluoride ions
Implementation Method 3
the electron-withdrawing effect of the halogen atom facilitates desorption of the ester group from the silicon atom
Data Source
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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 (80) 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), Ri 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.