LiPF6 Carbonate Electrolyte Stabilization Using Organosilicon Additives
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Solution Overview
Problem
Lithium hexafluorophosphate (LiPF6) and other alkali metal salts used in lithium-ion batteries are prone to degradation through various mechanisms, especially at elevated temperatures, which compromises the performance and stability of the electrolyte before and after formulation into batteries.
Innovation Solution
A stabilized salt-in-solvent mixture comprising an alkali metal salt, a carbonate solvent, and an organosilicon (OS) compound is introduced to inhibit thermal and chemical degradation by scavenging hydrogen ions and complexing with reactive species, thereby suppressing degradation reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alkali metal salts (LiPF6, NaPF6) are used as electrolyte conductors in lithium-ion batteries, then ionic conductivity and battery performance are improved, but the salts undergo thermal and chemical degradation at elevated temperatures, reducing stability and performance
Solution Approach 1:
The patent introduces organosilicon compounds as intermediary substances that mediate between the alkali metal salts and the degradation pathways. These OS compounds act as scavengers for reactive species (HF, H2O, CO2) that would otherwise cause salt degradation, thereby protecting the salt without directly altering its ionic conductivity properties
Solution Approach 2:
The patent extracts and removes the harmful reactive species (HF, H2O, CO2) from the system by introducing OS compounds that selectively bind and sequester these degradation-causing agents. This extraction of harmful components prevents them from attacking the alkali metal salts, thereby maintaining salt stability during storage
2Ease of manufacture
If alkali metal salts are stored and processed through multi-step electrolyte formulation before battery incorporation, then battery production is enabled, but the salts are susceptible to degradation throughout the storage and production process
Solution Approach 1:
The patent applies preliminary protective action by adding organosilicon compounds to the salt or electrolyte formulation before storage and processing. This preliminary stabilization ensures that the salts are protected from degradation throughout the entire electrolyte formulation process and storage period, maintaining their integrity from manufacturing through to battery incorporation
3Productivity
If elevated temperatures are encountered during storage or processing, then processing efficiency is improved, but degradation reactions of the salt are accelerated
Solution Approach 1:
The patent implements beforehand cushioning by pre-introducing organosilicon compounds that create a protective buffer against thermal degradation. These compounds are positioned in advance to scavenge reactive species that would be generated at elevated temperatures, cushioning the salt against thermal stress during storage and processing operations
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 mixture significantly enhances the storage stability of LiPF6-containing compositions, reducing hydrofluoric acid concentration and preventing carbonate decomposition, leading to improved shelf-life and performance of lithium-ion batteries.
Implementation Method 1
the OS compound suppresses degradation reactions within the salt-in-solvent mixture by scavenging hydrogen ions and complexing with reactive species
Implementation Method 2
the material has considerable sensitivity to degradation through several different mechanisms. These various degradation routes are accelerated at elevated temperatures
Data Source
AI summary
Disclosed herein is a stabilized salt-in-solvent mixture comprising a salt, a carbonate solvent, and an organosilicon (OS) compound, wherein the OS compound suppresses degradation reactions within the salt-in-solvent mixture. Also disclosed herein is a method of mitigating degradation of a salt/carbonate solution comprising adding to the salt/carbonate solution an amount of an OS compound that suppresses degradation reactions within the salt/carbonate solution. This OS compound may be added to the carbonate solvent before or after dissolution of the salt to form the salt-in-solvent mixture.