Sulfur Dioxide Electrolyte Salt Composition for Non-Flammable Li-Ion Cells
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrolyte compositions for lithium-ion batteries face challenges such as gasification during charging and discharging, reduced service life, and safety concerns due to the use of fluorinated solvents. Additionally, sulfur dioxide-based electrolytes have limited solubility for commonly used lithium conducting salts, restricting their application.
Innovation Solution
A novel electrolyte composition comprising sulfur dioxide as the solvent and a salt with an anionic complex comprising three bidentate ligands, specifically a lithium salt of the formula Li[P(O2C3(CF3)6)3], which provides enhanced ion conductivity, thermal stability, and hydrolysis resistance, thus addressing the limitations of previous electrolyte compositions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fluorinated solvents are used in electrolyte compositions, then electrochemical stability and wide voltage range operation are improved, but thermal safety deteriorates due to heat evolution and hazardous gas formation
Solution Approach 1:
The patent removes fluorinated solvents from the electrolyte composition entirely, replacing them with non-fluorinated alternatives. This extraction of the harmful component eliminates the source of thermal defects while maintaining electrochemical stability through the selected non-fluorinated solvent system and stable conducting salt combination
Solution Approach 2:
The patent converts the harmful thermal properties of fluorinated solvents into beneficial safety characteristics by selecting non-fluorinated solvents that are inherently more thermally stable and non-flammable. The harmful fluorinated compounds that cause heat evolution and HF gas formation are replaced with materials that provide intrinsic thermal safety while maintaining electrochemical performance
2Reliability
If sulfur dioxide is used as solvent in electrolyte composition, then ion conductivity and thermal stability are improved, but solubility of commonly used lithium conducting salts deteriorates
Solution Approach 1:
The patent changes the chemical parameters of the conducting salt by selecting a novel salt with an anionic complex comprising three bidentate ligands instead of commonly used salts like LiPF6. This parameter change in the salt's molecular structure enables high solubility in sulfur dioxide while maintaining high ion conductivity, resolving the contradiction between solubility and conductivity
Solution Approach 2:
The patent employs a composite electrolyte composition combining sulfur dioxide solvent with a specifically designed conducting salt featuring three bidentate ligands coordinated to a central metal atom. This composite material approach creates synergistic effects where the unique structure of the conducting salt complements the properties of sulfur dioxide, achieving both high solubility and high ion conductivity simultaneously
3Ease of operation
If organic electrolyte compositions are used in lithium-ion cells, then sufficient salt dissolution and ion mobility are achieved, but gasification occurs during charging and discharging leading to reduced service life
Solution Approach 1:
The patent changes the fundamental parameters of the electrolyte system by replacing organic solvents with sulfur dioxide as the solvent and using a novel conducting salt with three bidentate ligands. This parameter change shifts the electrochemical stability window and reduces gasification tendencies while maintaining ion mobility, thereby extending service life
Solution Approach 2:
The patent creates a more inert and stable electrolyte environment by using sulfur dioxide as the solvent, which provides a stable chemical atmosphere that resists decomposition and gasification during charging and discharging operations. This inert environment protects against unwanted redox reactions and extends the operational lifespan of the cell
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 proposed electrolyte composition achieves improved electrochemical performance, increased safety due to non-flammability, and cost-effectiveness, with enhanced recycling potential and reduced production costs, while maintaining high conductivity and stability across a wide temperature range.
Implementation Method 1
The current flow necessary therefor is achieved by ion transport of a conducting salt in the electrolyte composition. In the case of lithium-ion cells the conducting salt is a lithium conducting salt and lithium ions serve as the current-transporting ions.
Implementation Method 2
In addition to the lithium conducting salt electrolyte compositions contain a solvent, which ensures dissociation of the conducting salt and sufficient mobility of the lithium ions.
Data Source
AI summary
Liquid electrolyte compositions comprising a salt of the formula (I) which has an anionic complex comprising three bidentate ligands are provided. The complex comprises phosphorus as the central ion. Electrochemical cells comprising the liquid electrolyte composition are further provided. Salts of formula (I) are further provided.