Sultone Electrolyte Composition for Stable SEI at High Temperatures
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Solution Overview
Problem
Lithium secondary batteries face challenges in achieving high-temperature stability and long lifespan due to electrolyte decomposition reactions and the limitations of existing additives like 1,3-propane sultone, which are toxic and prone to gas generation.
Innovation Solution
A sultone-based compound represented by Formula I is introduced as an additive in a non-aqueous electrolyte solution, forming a stable and thin Solid Electrolyte Interface (SEI) layer, reducing flammability and enhancing high-temperature stability and lifespan by incorporating electron-withdrawing groups and sulfite/sulfate functional groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 1,3-propane sultone is used as an additive to form an SEI layer on the negative electrode, then the SEI layer formation is improved, but toxicity issues arise
Solution Approach 1:
The patent replaces the toxic 1,3-propane sultone additive with a safer alternative compound that performs the same SEI layer formation function. The new compound achieves the desired protective effect on the negative electrode without the harmful toxicity associated with the conventional additive, effectively substituting a harmful substance with a benign one that fulfills the same technical role.
2Object-generated harmful factors
If 1,3,2-dioxathiolane 2,2-dioxide is used as an additive, then gas generation is reduced, but chemical stability problems occur
Solution Approach 1:
The patent modifies the chemical structure of the additive compound to achieve the right balance between gas generation suppression and chemical stability. By adjusting molecular parameters such as the introduction of specific functional groups or structural modifications, the new compound reduces gas generation while maintaining adequate chemical stability, resolving the trade-off between these two competing requirements.
3Quantity of substance
If electrolyte decomposition reactions occur during repeated cycles, then high capacity is achieved, but resistance increases and lifespan deteriorates
Solution Approach 1:
The patent employs an additive compound that proactively forms a stable protective interface layer on the electrode surface before significant decomposition reactions can occur. This preliminary protective action prevents subsequent electrolyte decomposition and resistance increase during repeated cycling, thereby extending battery lifespan while maintaining capacity. The additive acts in advance to establish a protective barrier that mitigates harmful side reactions.
4Quantity of substance
If an SEI layer is formed to protect the positive electrode active material, then high energy density is achieved, but the SEI layer may collapse at high temperatures causing electrode exposure
Solution Approach 1:
The patent uses a composite additive compound that combines multiple functional characteristics within a single molecular structure. This composite approach creates an SEI layer with enhanced thermal stability while maintaining the protective function needed for high energy density. The multifunctional additive simultaneously provides mechanical stability, thermal resistance, and electrochemical protection, preventing SEI layer collapse at high temperatures.
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 compound effectively lowers the flammability of the electrolyte solution and forms a robust, low-resistance SEI layer, resulting in lithium secondary batteries with improved high-temperature storage and cycle properties.
Implementation Method 1
highly reactive lithium ions are reacted with an electrolyte to generate compounds such as Li2CO3, Li2O, and LiOH, and these compounds form a solid electrolyte interface (SEI) layer on the surface of an electrode
Implementation Method 2
A sultone-based compound represented by Formula I is introduced as an additive in a non-aqueous electrolyte solution, forming a stable and thin Solid Electrolyte Interface (SEI) layer, reducing flammability and enhancing high-temperature stability and lifespan
Data Source
AI summary
The present invention relates to a compound capable of lowering the flammability of a non-aqueous electrolyte when included in the non-aqueous electrolyte and improving the life properties of a battery by forming an electrode-electrolyte interface which is stable at high temperatures and low in resistance, and relates to a compound represented by Formula I descried herein, a non-aqueous electrolyte solution and a lithium secondary battery both including the compound,n, m, Ak, and X are described herein.