Lithium Battery Electrolyte Additive for Moisture-Driven Side Reactions
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Solution Overview
Problem
Rechargeable lithium batteries suffer from undesirable side reactions due to the reaction between lithium salts and moisture, leading to degradation and reduced performance, especially at high temperatures.
Innovation Solution
An electrolyte comprising a non-aqueous organic solvent, lithium salt, and an additive represented by Chemical Formula 1, which suppresses moisture and transition metal ion reactions, enhancing charging/discharging and high-temperature storage characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rechargeable lithium battery is continuously charged and discharged and/or stored at a high temperature, then the battery operates under normal conditions, but the lithium salt reacts with moisture to produce hydrogen fluoride and transition metal ions are eluted, causing degradation
Solution Approach 1:
The patent introduces a moisture scavenger as an intermediary substance that preferentially reacts with trace moisture in the electrolyte, preventing the moisture from reacting with lithium salts. The moisture scavenger acts as a mediator that absorbs water molecules through chemical or physical means, thereby eliminating the harmful interaction between moisture and lithium salts that would otherwise produce HF and cause electrode degradation
Solution Approach 2:
The patent converts the harmful presence of moisture into a beneficial effect by using the moisture scavenger to selectively bind water molecules. The trace moisture that would normally cause harmful side reactions is instead utilized as a target for the moisture scavenger, transforming the harmful factor into a controlled interaction that protects the battery components from degradation
2Reliability
If transition metal ions are eluted from the positive electrode active material, then the ions move through the electrolyte, but they precipitate as metals on the negative electrode surface and react with moisture to generate gas and increase resistance
Solution Approach 1:
The moisture scavenger serves as an intermediary that removes the moisture necessary for the harmful reaction of eluted transition metal ions. By scavenging moisture from the electrolyte environment, the moisture scavenger prevents the precipitation and subsequent reactive processes that would generate gas and increase resistance at the negative electrode
Solution Approach 2:
The moisture scavenger performs preliminary action by removing moisture from the electrolyte before transition metal ions can be eluted and before they can react with moisture to form harmful products. This preemptive removal of moisture prevents the chain of harmful events including ion elution, precipitation, and gas-generating reactions
3Ease of manufacture
If the electrolyte contains moisture, then the battery can be manufactured and assembled, but the moisture causes undesirable side reactions that accelerate degradation
Solution Approach 1:
The moisture scavenger acts as an intermediary substance included in the electrolyte composition that continuously binds trace moisture present during manufacturing and storage. This allows the battery to be assembled with practical moisture levels without suffering long-term degradation, as the moisture scavenger maintains a dry environment for the electrochemical components throughout storage and operation
Solution Approach 2:
The patent changes the chemical composition parameters of the electrolyte by adding a moisture scavenger component. This parameter change transforms the electrolyte from a passive medium to an active moisture-managing system, enabling the battery to tolerate higher initial moisture content during manufacturing while maintaining long-term stability through the moisture scavenger's continuous water-binding action
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 electrolyte effectively reduces reactions between lithium salts and moisture, minimizing degradation and improving battery performance and longevity.
Implementation Method 1
an additive represented by Chemical Formula 1... effectively removing moisture (e.g., H2O) in a rechargeable lithium battery
Implementation Method 2
an undesirable side reaction between a lithium salt (e.g., LiPF6) and moisture (e.g., H2O) may be suppressed or reduced
Implementation Method 3
side reactions with transition metal ions eluted from the positive electrode active material may be suppressed or reduced
Data Source
AI summary
An electrolyte for a rechargeable lithium battery and a rechargeable lithium battery are disclosed. The electrolyte for a rechargeable lithium battery may include a non-aqueous organic solvent; a lithium salt; and an additive represented by Chemical Formula 1.R-L-N═C═O Chemical Formula 1