Electrolyte Additive for Lithium Battery SEI Stability
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Solution Overview
Problem
Lithium secondary batteries face issues with structural deformation and side reactions between lithium metal oxide and electrolyte, leading to reduced lifespan and stability, especially when charged at high temperatures or overcharged.
Innovation Solution
An electrolyte solution for lithium secondary batteries is developed, comprising an organic solvent, a lithium salt, and an additive represented by Chemical Formula 1, which forms a stable solid-electrolyte interphase (SEI) on the cathode surface, suppressing side reactions and enhancing capacity retention at room and high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If lithium secondary battery is repeatedly charged and discharged, then battery capacity is maintained, but structural deformation of lithium metal oxide and side reactions with electrolyte occur, deteriorating life-span properties
Solution Approach 1:
The patent introduces a film-forming additive as an intermediary substance between the lithium metal oxide cathode and the electrolyte. This additive forms a protective interface film that mediates the interaction between the cathode and electrolyte, preventing direct harmful reactions while allowing lithium ion transport. The additive acts as a buffer layer that resolves the contradiction between maintaining battery operation and preventing chemical degradation.
Solution Approach 2:
The film-forming additive performs preliminary protective action by forming a stable interface film on the cathode surface before significant degradation can occur. This preliminary film prevents structural deformation of lithium metal oxide and side reactions with the electrolyte during subsequent charging and discharging cycles, thereby extending battery lifespan while maintaining chemical stability.
2Power
If lithium secondary battery is charged at high temperature or over-charged, then battery performance is enhanced, but stability of the lithium secondary battery is further degraded
Solution Approach 1:
The film-forming additive serves as a protective intermediary that becomes particularly important under high temperature and overcharge conditions. The interface film formed by the additive prevents thermal runaway and stabilizes the cathode structure during high-performance operation, allowing the battery to deliver high power while maintaining stability that would not be achievable with conventional electrolytes alone.
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 solution improves chemical stability, capacity retention, and resistance, while preventing battery thickness increase and resistance growth during high-temperature storage, thereby extending the battery's lifespan and enhancing its high-temperature performance.
Implementation Method 1
An electrolyte solution for lithium secondary batteries is developed, comprising an organic solvent, a lithium salt, and an additive represented by Chemical Formula 1, which forms a stable solid-electrolyte interphase (SEI) on the cathode surface
Data Source
Figure 1~2
AI summary
An electrolyte solution for a lithium secondary battery includes an organic solvent, a lithium salt, and an additive including a compound represented by Chemical Formula 1. A lithium secondary includes the electrolyte solution and has improved capacity retention at room temperature and high temperature storage properties such as increased capacity retention and capacity recovery and an suppressed resistance and thickness.