Non-Aqueous Electrolyte Additive for SEI Protection at High Temperature
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing non-aqueous electrolytes for lithium secondary batteries face issues with high-temperature stability and lifespan due to the generation of Lewis acids like PF5, which decompose the organic solvent and destroy the solid electrolyte interface layer (SEI) at the negative electrode, leading to reduced durability.
Innovation Solution
Incorporation of a compound represented by Chemical Formula 1, which acts as a Lewis base to neutralize Lewis acids, preventing solvent decomposition and enhancing the formation of a stable SEI layer, thereby improving high-temperature storage and lifespan characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If LiPF6 or similar lithium salts with PF6- anions are used, then electrochemical performance is improved, but Lewis acids such as PF5 are generated due to thermal decomposition at high temperatures, causing decomposition of the organic solvent and destruction of the SEI layer
Solution Approach 1:
A compound containing a cyano group is introduced as an intermediary substance that selectively reacts with Lewis acids (PF5) generated from lithium salt decomposition. This intermediary captures the harmful Lewis acid through coordinate bonding, preventing it from attacking the organic solvent and SEI layer, thus resolving the contradiction between maintaining electrochemical performance and ensuring high-temperature stability
Solution Approach 2:
The invention converts the harmful effect of Lewis acid generation into a beneficial process by directing the Lewis acid to react with the cyano group-containing compound instead of damaging components. The Lewis acid that would otherwise cause degradation is now utilized to form a protective interaction with the additive, transforming a harmful byproduct into a controlled reaction that protects the battery system
2Ease of operation
If conventional non-aqueous electrolytes are used, then battery operation is maintained, but the SEI layer is destroyed by Lewis acids at high temperatures, leading to reduced lifespan and durability
Solution Approach 1:
The cyano group-containing compound is预先 introduced into the electrolyte system to perform preliminary protection against Lewis acid formation. Before the Lewis acid can damage the SEI layer or cause solvent decomposition, the additive is already in position to capture it through coordinate bonding, preventing the harmful effects before they occur and thereby extending battery lifespan while maintaining operation
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 compound in the non-aqueous electrolyte effectively removes Lewis acids, maintaining the integrity of the SEI layer and enhancing the battery's high-temperature performance and lifespan.
Implementation Method 1
the compound included in the non-aqueous electrolyte solution according to the present disclosure can play a role in removing the Lewis acid generated from the lithium salt when the lithium secondary battery is exposed to high temperatures, thus preventing the decomposition of the organic solvent caused by the Lewis acid
Implementation Method 2
since the compound represented by the specific Chemical Formula has a low LUMO energy level, it can participate in the formation reaction of the SEI layer of the negative electrode
Data Source
AI summary
The present invention relates to a non-aqueous electrolyte comprising a lithium salt; an organic solvent; and a compound represented by Chemical Formula 1, wherein the invention can control moisture in the lithium secondary battery in which the non-aqueous electrolyte is used, suppress by-product formation according to moisture control, and improve the durability of the solid electrolyte layer, thereby improving the durability thereof,wherein L1 and L2 are each independently a single bond or an alkylene group having 1 to 5 carbon atoms, and R1 is hydrogen or an alkyl group having 1 to 5 carbon atoms.