Non-Aqueous Electrolyte Composition for High-Temperature Li-Ion Stability
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Solution Overview
Problem
Lithium secondary batteries face degradation issues due to transition metal ion dissolution from the positive electrode, leading to degradation of the solid electrolyte interphase (SEI) and swelling, particularly at high temperatures, which affects their stability and performance.
Innovation Solution
A non-aqueous electrolyte containing a specific organic solvent, represented by Formula 1, is used to suppress positive electrode degradation, form a stable SEI film on the negative electrode, and reduce side reactions, thereby improving high-temperature cycle and storage characteristics.
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 non-aqueous electrolyte minimizes gas generation and enhances electrode-electrolyte interface stability, resulting in improved lithium secondary battery performance at high temperatures with reduced degradation.
Implementation Method 1
A method of producing lithium fluorosulfonate which comprises reacting fluorosulfonic acid with a lithium salt in a non-aqueous solvent
Implementation Method 2
non-aqueous electrolytic solution containing lithium fluorosulfonate
Data Source
AI summary
The present invention provides a non-aqueous electrolyte including a lithium salt and an organic solvent, wherein the non-aqueous electrolyte includes a compound represented by Formula 1 as the organic solvent, and includes the compound represented by Formula 1 in an amount of 25 wt% to 80 wt% based on the total non-aqueous electrolyte: wherein, in Formula 1, R1 and R2 are each independently any one selected from the group consisting of hydrogen (H), an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an alkynyl group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 12 carbon atoms, a cycloalkenyl group having 3 to 12 carbon atoms, and an aryl group having 6 to 20 carbon atoms, and X may be a perfluoroalkyl group having 1 to 5 carbon atoms.