Dinitrile Electrolyte Additives for Lithium Battery Swelling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries experience swelling phenomena due to oxidation of organic solvents at high temperatures, leading to potential internal shorts and explosions, which existing additives have not effectively addressed.
Innovation Solution
A non-aqueous electrolyte solution comprising an organic solvent, ionizable lithium salt, a dinitrile compound with an ether bond such as ethylene glycol bis(2-cyanoethyl)ether, and an aliphatic dinitrile compound like succinonitrile, which forms a stable solid electrolyte interphase and prevents oxidation reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the charging voltage is increased to increase capacity, then the capacity is improved, but the structural stability of the cathode deteriorates due to accelerated transition metal desorption
Solution Approach 1:
A film-forming additive is introduced as an intermediary substance between the cathode and electrolyte. This additive forms a protective interface film that mediates the interaction, preventing transition metal desorption while allowing lithium ion transport, thus maintaining capacity without compromising structural stability
Solution Approach 2:
The chemical composition and physical properties of the electrolyte are modified by adding specific film-forming compounds. This changes the parameters of the electrolyte-cathode interface, creating a stable solid electrolyte interphase that prevents structural degradation at high charging voltages
2Quantity of substance
If organic solvents are stored at high temperature for a long time, then the battery energy density is maintained, but the electrolyte solution is oxidized to generate gas causing swelling
Solution Approach 1:
A film-forming additive is added to the electrolyte that proactively forms a protective film on the cathode surface before oxidation can occur. This preliminary protective layer prevents the oxidation of organic solvents and subsequent gas generation, even during long-term high-temperature storage
Solution Approach 2:
The film-forming additive sacrifices itself by forming a stable interface film that would otherwise be consumed by oxidation. This converts the potentially harmful oxidation reaction into a beneficial protective layer formation, preventing gas generation and swelling
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 restrains swelling and improves the charging/discharging cycle lifetime by preventing gas generation and internal pressure increases, even at high temperatures, thereby enhancing the safety and performance of lithium secondary batteries.
Implementation Method 1
forming a stable solid electrolyte interphase
Implementation Method 2
prevents oxidation reactions
Implementation Method 3
ionizable lithium salt
Implementation Method 4
non-aqueous electrolyte solution obtained by dissolving an appropriate amount of a lithium salt into an organic solvent mixture
Data Source
Figure 1
AI summary
A non-aqueous electrolyte solution for a lithium secondary battery and a lithium secondary battery including the same are provided. The non-aqueous electrolyte solution includes an organic solvent, an ionizable lithium salt, a dinitrile compound including an ether bond represented by Chemical Formula 1, and an aliphatic dinitrile compound represented by Chemical Formula 2. The lithium secondary battery including the non-aqueous electrolyte solution having the possibility of generating a swelling phenomenon while storing or charging/discharging at a high temperature may be restrained. In addition, a cycle life of the charging/discharging may be improved.