Lithium Battery Electrolyte Additive for High-Temperature Cycle Life
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Solution Overview
Problem
The existing lithium secondary batteries face issues with high-temperature performance degradation due to the decomposition of LiPF6, leading to electrolyte depletion and poor safety, necessitating an electrolyte that suppresses side reactions and improves battery performance.
Innovation Solution
An electrolyte containing a specific additive represented by Chemical Formula 1, which includes a dithioester functional group, forms a film on electrode surfaces to stabilize the positive electrode, reducing resistance and enhancing high-temperature cycle-life characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiPF6 is used as a lithium salt in the electrolyte, then the battery can achieve good electrochemical performance, but LiPF6 decomposes at high temperatures to generate gas and promote electrolyte depletion, leading to poor high-temperature performance and safety issues
Solution Approach 1:
The patent introduces a novel lithium salt compound as an intermediary substance that mediates between the need for good electrochemical performance and the need to suppress high-temperature decomposition. This lithium salt compound exhibits both excellent electrochemical properties and high thermal stability, acting as a bridge to resolve the contradiction between performance and stability.
Solution Approach 2:
The patent changes the chemical composition parameters of the lithium salt by incorporating specific ratios of LiPF6 (5-50 wt%), LiBF4 (30-70 wt%), and LiCF3SO3 (10-40 wt%). By adjusting these compositional parameters, the electrolyte achieves optimal balance between electrochemical performance and high-temperature stability, preventing decomposition while maintaining functionality.
2Temperature
If the electrolyte operates at high temperatures, then the battery can maintain operation under elevated conditions, but side reactions accelerate leading to electrolyte depletion and performance degradation
Solution Approach 1:
The patent applies preliminary anti-action by formulating an electrolyte composition that preemptively resists high-temperature side reactions. The specific combination of lithium salts and additives creates a stable chemical environment that prevents decomposition reactions before they can occur, thereby preventing electrolyte depletion and maintaining substance integrity under elevated temperatures.
Solution Approach 2:
The patent uses a composite electrolyte system combining multiple lithium salts (LiPF6, LiBF4, LiCF3SO3) with specific additives at defined concentrations. This composite material approach leverages the synergistic effects of different components to achieve both high-temperature stability and resistance to electrolyte depletion, allowing operation across a wide temperature range without significant substance loss.
3Ease of manufacture
If conventional electrolyte composition is used, then the battery can be manufactured with standard processes, but the high-temperature cycle-life characteristics are poor due to resistance increase and performance degradation
Solution Approach 1:
The patent modifies the electrolyte composition parameters by specifying precise ranges for lithium salt concentrations (LiPF6: 5-50 wt%, LiBF4: 30-70 wt%, LiCF3SO3: 10-40 wt%) and additive content (0.1-5 wt%). These parameter changes enhance high-temperature cycle-life characteristics and reduce resistance increase while maintaining compatibility with existing manufacturing processes, thus improving duration without significantly increasing manufacturing complexity.
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 additive improves the lithium secondary battery's high-temperature cycle-life characteristics by preventing resistance increase and maintaining battery performance under elevated temperatures.
Implementation Method 1
forms a film on electrode surfaces to stabilize the positive electrode
Data Source
AI summary
Provided are an additive represented by Chemical Formula 1, an electrolyte for a lithium secondary battery including same, and a lithium secondary battery. The details of Chemical Formula 1 are as described in the specification.