Non-Aqueous Electrolyte Additives for Lithium Battery Swelling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries experience cell swelling and capacity degradation due to side reactions between the non-aqueous electrolyte solution and the positive electrode, especially under high-voltage and high-temperature conditions, leading to transition metal ion dissolution and electrolyte decomposition.
Innovation Solution
A non-aqueous electrolyte solution for lithium secondary batteries is developed, incorporating 1,4-dicyano-2-butene (DCB) and a compound with a specific structure, which forms a robust film on the positive electrode surface, preventing side reactions and metal ion dissolution, thereby reducing cell swelling and improving capacity characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the voltage increases or the storage temperature increases, then the energy density and operating voltage are improved, but the side reaction between the non-aqueous electrolyte solution and the positive electrode surface is intensified, leading to battery swelling and cycle degradation
Solution Approach 1:
The patent applies preliminary action by forming a protective film on the positive electrode surface before harmful side reactions can occur. The fluorinated cyclic carbonate compound reacts with transition metal ions on the electrode surface during initial cycles to create a stable coating layer, which prevents subsequent electrolyte decomposition and electrode collapse during high-voltage operation and storage
Solution Approach 2:
The fluorinated cyclic carbonate compound acts as an intermediary substance between the electrolyte and the positive electrode. This compound forms a mediating protective layer that allows beneficial ionic transport while blocking harmful direct reactions between the electrolyte and electrode, thus enabling high-voltage operation without proportional increase in degradation
2Quantity of substance
If the voltage increases, then the energy density is improved, but the film formed on the positive electrode surface degrades, causing transition metal ion dissolution and gas generation
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition of the protective film through the use of fluorinated cyclic carbonate compound. The fluorine atoms in the compound change the film's chemical properties, increasing its electrochemical stability and resistance to degradation at high voltages, thereby maintaining film integrity while enabling higher energy density operation
3Productivity
If the storage temperature increases, then the capacity characteristics are improved, but the side reaction between the electrolyte solution and the positive electrode is intensified, leading to cell swelling
Solution Approach 1:
The patent applies preliminary anti-action by pre-forming a stable protective film that actively prevents harmful side reactions before they can occur during high-temperature storage. The fluorinated cyclic carbonate compound creates a thermally stable coating that resists electrolyte decomposition even at elevated temperatures, thereby preventing gas generation and cell swelling while maintaining capacity characteristics
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 suppresses electrolyte decomposition, prevents positive electrode collapse, and enhances high-temperature storage stability and capacity retention by forming a stable film that reduces metal ion dissolution and gas generation, resulting in improved battery performance and extended cycle life.
Implementation Method 1
1,4-dicyano-2-butene (DCB) and a compound represented by Formula 1, which are included in a non-aqueous electrolyte solution of the present invention, are compounds containing a nitrile (—CN) group in their structures, wherein they may form a robust film on a surface of a positive electrode by strong binding with transition metal
Data Source
AI summary
A non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery including the same are disclosed herein. In some embodiments, a non-aqueous electrolyte solution for a lithium secondary battery includes a lithium salt, an organic solvent, and an additive, wherein the additive includes 1,4-dicyano-2-butene (DCB) and a compound represented by Formula 1.