Lithium Battery Electrolyte Additive for LiPF6 By-Product Neutralization
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Solution Overview
Problem
The degradation of lithium secondary batteries due to side reactions caused by by-products generated from lithium salt decomposition at high temperatures, leading to increased resistance and reduced capacity, is not effectively addressed by existing technologies.
Innovation Solution
Incorporation of a Lewis base-based compound, represented by Formula 1, which includes a nitrogen-containing heteroaryl group, into the electrolyte solution to react with and neutralize the by-products, thereby stabilizing the solid electrolyte interphase (SEI) and preventing further decomposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiPF6 lithium salt is used in the electrolyte solution, then high ionic conductivity is achieved, but decomposition products (HF and PF5) are generated at high temperatures causing SEI film deterioration and additional electrolyte decomposition
Solution Approach 1:
A nitrogen-containing heterocyclic compound is introduced as an intermediary substance that preferentially reacts with the decomposition products (HF and PF5) generated from LiPF6. This intermediary additive acts as a buffer, capturing the harmful by-products before they can attack the SEI film, thereby protecting the system while maintaining the benefits of LiPF6 usage
Solution Approach 2:
The harmful decomposition products (HF and PF5) are converted into beneficial effects through the nitrogen-containing heterocyclic compound, which reacts with these by-products to form stable complexes. This transforms the harmful acid attack into a controlled chemical reaction that protects the SEI film and prevents further electrolyte decomposition
2Productivity
If high temperature storage is performed, then battery capacity is reduced due to side reactions from electrolyte decomposition, but operational requirements demand high-temperature performance
Solution Approach 1:
The nitrogen-containing heterocyclic compound performs preliminary action by reacting with decomposition products as they are generated during high-temperature storage, preventing the accumulation of harmful substances that would otherwise cause SEI film collapse and capacity loss. This proactive protection mechanism maintains battery performance throughout high-temperature storage periods
3Stability of the object's composition
If the SEI film passivation ability is insufficient, then additional electrolyte decomposition occurs during storage causing self-discharge and potential reduction, but enhancing SEI stability requires effective suppression of decomposition products
Solution Approach 1:
The nitrogen-containing heterocyclic compound serves as a protective intermediary that absorbs the acid attack from HF and PF5, preventing direct contact with the SEI film. This mediator maintains the integrity and passivation ability of the SEI film during high-temperature storage by neutralizing harmful decomposition products
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 proposed electrolyte solution enhances high-temperature storage characteristics and maintains initial capacity by suppressing continuous decomposition reactions, resulting in reduced resistance and improved battery performance.
Implementation Method 1
a Lewis base-based compound, represented by Formula 1, which includes a nitrogen-containing heteroaryl group, into the electrolyte solution to react with and neutralize the by-products, thereby stabilizing the solid electrolyte interphase (SEI)
Data Source
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AI summary
The present invention relates to an electrolyte for a lithium secondary battery, and a lithium secondary battery comprising same, the electrolyte comprising: lithium salt; an additive including a compound represented by chemical formula 1; and an organic solvent.