Silyl Electrolyte Additives for High-Voltage Li-Ion Stability
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Solution Overview
Problem
Li-ion batteries face stability issues at high voltages due to cathode material oxidation and SEI breakdown, leading to increased interfacial resistance and capacity loss, especially at extreme temperatures, necessitating improved electrolyte components for next-generation batteries.
Innovation Solution
The development of a silyl-based compound additive with phosphorus-sulfur bonds, combined with an aprotic organic solvent system and metal salts, forms a stable SEI layer, enhancing high-voltage stability and temperature resilience in lithium-ion battery electrolytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If Li-ion batteries operate at high voltages above 4.35 V to increase capacity and energy density, then energy density is improved, but cathode material stability deteriorates due to increased oxidation
Solution Approach 1:
The patent introduces silyl-based phosphoric acid derivative compounds as intermediary substances in the electrolyte that mediate between the high-voltage cathode and the electrolyte. These compounds form protective interfacial layers that prevent direct oxidation reactions, enabling high-voltage operation while maintaining cathode stability.
Solution Approach 2:
The patent modifies the electrolyte composition by incorporating specific silyl-based phosphoric acid derivatives with controlled molecular structures. These parameter changes in electrolyte chemistry enable the system to withstand higher voltages by altering the electrochemical window and interfacial properties.
2Quantity of substance
If cathode active material is used at high voltages to increase capacity, then battery capacity is improved, but interfacial resistance increases due to material dissolution
Solution Approach 1:
The silyl-based phosphoric acid derivative compounds act as intermediary agents that form stable interfacial films between the cathode material and electrolyte. This intermediary layer prevents material dissolution while maintaining ionic conductivity, thus increasing capacity without proportionally increasing interfacial resistance.
Solution Approach 2:
The patent creates a composite interfacial structure through the reaction of silyl-based additives with cathode surfaces, forming composite material layers that combine the benefits of high capacity utilization with low interfacial resistance through optimized chemical composition and structure.
3Adaptability or versatility
If Li-ion batteries are exposed to extreme temperatures during operation, then operational flexibility is improved, but SEI layer stability deteriorates leading to capacity loss
Solution Approach 1:
The patent introduces silyl-based phosphoric acid derivatives that modify the SEI layer composition and structure through parameter changes in electrolyte chemistry. These modifications create a more thermally stable SEI layer that maintains integrity across a wider temperature range, enabling flexible operation without sacrificing stability.
4Ease of operation
If traditional carbonate-based electrolytes are used to transport lithium ions, then ionic conductivity is maintained, but high-voltage stability is insufficient
Solution Approach 1:
The patent creates a composite electrolyte system by combining traditional carbonate-based solvents with silyl-based phosphoric acid derivative additives. This composite approach maintains the excellent ionic conductivity of carbonates while adding high-voltage stability through the protective effects of the silyl-based compounds.
Solution Approach 2:
The patent achieves high-voltage stability while maintaining ionic conductivity through parameter changes in electrolyte composition, specifically by optimizing the concentration and molecular structure of silyl-based phosphoric acid derivatives to balance conductivity and stability properties.
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 silyl-based additive improves ionic conductivity and forms a stable silicon-containing film on electrodes, enhancing the performance and cycle life of Li-ion batteries at high voltages and varying temperatures, addressing the limitations of traditional electrolytes.
Implementation Method 1
the SEI (Solid Electrolyte Interface) layer formed on the anode is gradually broken down
Implementation Method 2
These electrolytes need functional additives to passivate the anode and form a stable SEI layer
Implementation Method 3
The shuttling of positive and negative ions between the battery electrodes is the main function of the electrolyte
Implementation Method 4
The electrolyte with these silyl-based additives has high ionic conductivity
Data Source
AI summary
An electrolyte additive containing a silyl-group compound useful for reducing battery resistance and improving high-temperature performance; an electrolyte containing the silyl-group compound additive; and an electrochemical energy storage device containing the electrolyte are disclosed.