Disulfone-Based Electrolyte for Lithium Battery SEI Stability
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Solution Overview
Problem
Lithium batteries face challenges in forming stable solid electrolyte interface (SEI) and protection layers, leading to reduced lifespan characteristics due to irreversible reactions between electrodes and organic electrolytic solutions, especially at high temperatures.
Innovation Solution
An electrolytic solution for lithium batteries comprising a lithium salt, an organic solvent, a disultone-based compound, and a non-polar unsaturated group-containing cyclic carbonate-based compound, which enhances the formation of stable SEI and protection layers by facilitating electron acceptance and radical formation, thereby improving battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a carbonate-based polar non-aqueous solvent is used in a lithium battery, then the electrolytic solution can dissolve lithium salt and provide ionic conductivity, but it causes side reactions between electrodes and electrolytic solution during initial charging, leading to irreversible reactions and reduced lifespan
Solution Approach 1:
The patent introduces a disultone-based compound as an intermediary substance in the electrolytic solution. This compound acts as a mediator that facilitates the formation of stable SEI and protection layers, preventing direct harmful interactions between the carbonate-based solvent and electrode surfaces. The disultone-based compound accepts electrons and forms radicals that reconstruct the electrode-electrolyte interface, eliminating the need for harmful side reactions while still enabling stable operation.
2Reliability
If the SEI layer and protection layer are formed through irreversible reactions, then the electrodes are protected from further decomposition, but the battery loses excess charges and experiences reduced lifespan characteristics
Solution Approach 1:
The patent changes the chemical parameters of the electrolytic solution by incorporating a disultone-based compound with specific molecular structure (Formula 1) containing sulfur and oxygen atoms. This parameter change transforms the nature of the initial charging reactions from harmful irreversible side reactions to controlled radical formation and electron acceptance processes. The disultone-based compound's unique chemical structure enables it to form protective layers while minimizing charge loss, thereby improving lifespan characteristics without excessive energy waste.
3Reliability
If the protection layer on the positive electrode is made more stable at high temperature, then the battery lifespan is improved, but the formation process becomes more complex and requires specific compound combinations
Solution Approach 1:
The patent employs a composite electrolytic solution formulation that combines a disultone-based compound (Formula 1) with conventional lithium salts and organic solvents. This composite approach leverages the synergistic effects of different components: the disultone-based compound provides high-temperature stability through its sulfur-containing structure, while the conventional components maintain ionic conductivity and solubility. The composite material strategy achieves enhanced protection layer stability without requiring complete redesign of the electrolytic system.
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 electrolytic solution significantly improves the lifespan characteristics of lithium batteries by forming more stable SEI and protection layers, maintaining their firm state during charging and discharging, and maintaining high-temperature stability.
Implementation Method 1
enhances the formation of stable SEI and protection layers by facilitating electron acceptance and radical formation
Implementation Method 2
The organic electrolytic solution may be prepared by dissolving a lithium salt in an organic solvent. A suitable organic solvent may be stable at high voltages, may have a high ionic conductivity
Implementation Method 3
The SEI layer may prevent or substantially reduce decomposition of the electrolyte and may also serve as an ion channel
Implementation Method 4
The protection layer may prevent or substantially reduce decomposition of the electrolytic solution during charging and discharging and may serve as an ion tunnel
Data Source
AI summary
An electrolytic solution for a lithium battery includes a lithium salt, an organic solvent; a disultone-based compound represented by Formula 1, and a non-polar unsaturated group-containing cyclic carbonate-based compound:wherein, in Formula 1, A1 to A4 are each independently a substituted or unsubstituted C1-C5 alkylene group, a carbonyl group, or a sulfinyl; n1 to n4 are each independently an integer 1 to 3, and when n1 to n4 are each independently two or greater, a respective plurality of any of A1s to A4s are identical to or different from each other. When the lithium battery includes the electrolyte solution, room-temperature and high-temperature lifespan characteristics of the lithium battery may improve.