Non-Aqueous Battery Electrolyte for Fast Charging at Low Temperature
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Solution Overview
Problem
Lithium secondary batteries face challenges with rapid charging performance and low-temperature output characteristics due to the limitations of existing non-aqueous electrolytes, particularly ethylene carbonate, which leads to lithium precipitation and degraded performance.
Innovation Solution
A non-aqueous electrolyte solution for lithium secondary batteries comprising specific additives, including compounds represented by Formulas 1 and 2, along with vinylene carbonate and vinylethylene carbonate, to form films with lower resistance and improve durability, enhancing rapid charging and low-temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods (ammonium fluorosulfonate mixed with lithium hydroxide aqueous solution) are used to produce lithium fluorosulfonate, then lithium fluorosulfonate can be obtained, but the production process becomes complex and contamination with ammonia occurs
Solution Approach 1:
The invention extracts and eliminates the problematic intermediate step involving ammonium fluorosulfonate and cation exchange. Instead of using the conventional two-step process (forming ammonium salt then exchanging cations), the patent directly synthesizes lithium fluorosulfonate by reacting fluorosulfonic acid with lithium salt in non-aqueous solvent, removing the source of ammonia contamination and process complexity
Solution Approach 2:
The invention introduces a non-aqueous solvent as an intermediary medium to enable direct reaction between fluorosulfonic acid and lithium salt. This intermediary allows the reaction to proceed without forming the problematic ammonium intermediate, achieving both simplification and high purity
2Productivity
If LiClO4 is used as electrolyte, then electrolyte can be provided, but active oxygen is formed due to decomposition at electropositive potential which attacks the solvent and accelerates decomposition
Solution Approach 1:
The invention changes the chemical composition parameter of the electrolyte from LiClO4 to lithium fluorosulfonate (LiFSO3). This parameter change fundamentally alters the decomposition behavior at electropositive potentials, preventing the formation of active oxygen while maintaining high discharge capacity and improving battery performance
3Productivity
If CF3SO3Li, LiBF4 or LiPF6 are used as electrolyte, then electrolyte can be provided, but fluorine is formed due to decomposition at electropositive potential which attacks the solvent and accelerates decomposition
Solution Approach 1:
The invention changes the electrolyte composition from fluorine-containing salts (CF3SO3Li, LiBF4, LiPF6) to lithium fluorosulfonate. Although lithium fluorosulfonate contains fluorine in its structure, the fluorine is bonded in a stable configuration that prevents decomposition and release of free fluorine at electropositive potentials, thereby eliminating solvent attack while maintaining high productivity
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 capacity retention rates and reduces lithium precipitation during rapid charging, ensuring stable operation in various environments.
Implementation Method 1
A method involving the reaction of fluorosulfonic acid with a specific lithium salt in a non-aqueous solvent to produce high-purity lithium fluorosulfonate
Implementation Method 2
non-aqueous electrolytic solution containing lithium fluorosulfonate
Data Source
AI summary
The present invention relates to a non-aqueous electrolyte solution for a lithium secondary battery comprising an organic solvent; a lithium salt; a first additive which is a compound represented by Formula 1; a second additive which is a compound represented by Formula 2; and a third additive which is one or more selected from the group consisting of vinylene carbonate and vinylethylene carbonate, and a lithium secondary battery comprising the non-aqueous electrolyte solution.