Sulfur Dioxide Electrolyte Composition for Safer Li-Ion Cells
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Solution Overview
Problem
Lithium-ion cells face issues with thermal stability, hydrolysis resistance, and safety due to the use of conventional organic electrolytes, which lead to reduced performance and operational risks, especially when dealing with high temperatures and deep discharging.
Innovation Solution
A liquid electrolyte composition using sulfur dioxide as a solvent and chelate complexes with bidentate ligands as conductive salts, which are chemically and electrochemically stable, ensuring high ionic conductivity and safety by forming non-flammable solvate complexes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional organic electrolytes are used in lithium-ion cells, then the cells can operate with standard electrolyte composition, but the thermal stability and hydrolysis resistance are reduced
Solution Approach 1:
The patent changes the fundamental chemical parameters of the electrolyte by replacing conventional organic carbonates with sulfur dioxide as the solvent and using chelate complexes as conductive salts. This parameter change transforms the electrolyte from flammable organic-based to non-flammable inorganic-based, directly resolving the thermal stability issue while maintaining ionic conductivity through the chelate complex structure.
Solution Approach 2:
The patent employs composite material strategy by combining sulfur dioxide solvent with chelate complexes containing bidentate ligands and metal ions (Li+, Na+, K+, Ca2+, Mg2+). This composite approach creates a new electrolyte system where the chelate structure provides both ionic conductivity and enhanced thermal stability, overcoming the limitations of conventional single-component electrolytes.
2Reliability
If conventional organic electrolytes are used, then the electrolyte composition is simple, but the resistance to hydrolysis is reduced
Solution Approach 1:
The patent changes the chemical composition parameters by introducing sulfur dioxide and chelate complexes, which fundamentally alter the electrolyte's resistance to hydrolysis. The chelate structure with bidentate ligands creates a stable complex that resists hydrolytic decomposition, directly improving hydrolysis resistance despite the increased compositional complexity.
3Reliability
If conventional organic electrolytes are used, then the electrolyte can provide sufficient ionic conductivity, but the safety is reduced due to flammability
Solution Approach 1:
The patent fundamentally changes the safety parameter by replacing flammable organic carbonates with non-flammable sulfur dioxide. This parameter change eliminates the fire hazard inherent in conventional electrolytes while the chelate complexes maintain the necessary ionic conductivity for battery operation, thus improving safety without sacrificing performance.
Solution Approach 2:
The patent converts the potential harm of using inorganic sulfur dioxide (which could be toxic or reactive) into a benefit by forming stable chelate complexes. The chelate structure tames the reactivity of sulfur dioxide, transforming it from a potentially harmful substance into a safe, non-flammable electrolyte medium that provides both safety and ionic conductivity.
4Reliability
If chelate complexes with bidentate ligands are used as conductive salts, then the ionic conductivity is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The patent changes the conductive salt parameter from conventional simple salts to chelate complexes with bidentate ligands. This parameter change enhances ionic conductivity through the stable complex structure that facilitates ion transport. The manufacturing complexity is managed by selecting from a defined set of metal ions and ligand types, making the synthesis process systematic rather than arbitrary.
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 composition enhances the thermal stability, hydrolysis resistance, and safety of lithium-ion cells, allowing for efficient charge balancing and extended service life while enabling cost-effective recycling and reducing environmental impact.
Implementation Method 1
A liquid electrolyte composition using sulfur dioxide as a solvent and chelate complexes with bidentate ligands as conductive salts, which are chemically and electrochemically stable, ensuring high ionic conductivity
Implementation Method 2
The flow of current required for this is achieved by the ion transport of a conductive salt in the electrolyte composition
Data Source
AI summary
A liquid electrolyte composition for an electrochemical cell is provided. The liquid electrolyte composition includes the following components: (A) sulfur dioxide; (B) at least one salt containing an anionic complex with at least one bidentate ligand. The ligand along with a central ion Z of the anionic complex forms a five to eight-membered ring containing a sequence of 2 to 5 carbon atoms, said sequence being optionally interrupted by a heteroatom.