Purified Bis(Fluorosulfonyl)Imide Ionic Liquid for Stable Battery Electrolytes
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Solution Overview
Problem
Lithium-ion batteries face challenges in achieving long battery lifetime and safety due to the instability of electrolyte interfaces and flammability of solvents, with existing solutions compromising ionic conductivity.
Innovation Solution
Development of an ionic liquid with a bis(fluorosulfonyl)imide anion and onium cation, purified using activated carbon decolorization and aqueous washing, resulting in an electrolyte with improved electrochemical stability and reduced flammability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fluorinated solvents are used to avoid flammability, then safety is improved, but ionic conductivity is reduced
Solution Approach 1:
The invention changes the chemical composition parameters by using ionic liquids with specific anions (FSO3-, CF3SO3-, PF6-) and cations (imidazolium, pyridinium, ammonium, phosphonium) to achieve non-flammability while maintaining high ionic conductivity. This parameter optimization resolves the contradiction between safety and conductivity
Solution Approach 2:
The invention uses composite ionic liquid formulations combining different cation-anion pairs to achieve both non-flammability and high ionic conductivity. The composite nature of these ionic liquids allows optimization of multiple properties simultaneously, resolving the trade-off between safety and conductivity
2Object-affected harmful factors
If substantial amounts of ionic liquid are used to make the electrolyte nonflammable, then safety is improved, but electrochemical stability must be enhanced to maintain battery longevity
Solution Approach 1:
The invention optimizes the chemical parameters of ionic liquids by selecting specific stable anions (FSO3-, CF3SO3-, PF6-) and cations with proven electrochemical stability. This parameter selection ensures both non-flammability and long-term electrochemical stability, resolving the contradiction between safety and battery lifetime
Solution Approach 2:
The invention uses commercially available ionic liquids with established stability profiles, allowing for cost-effective implementation without compromising battery longevity. The use of well-characterized ionic liquid systems ensures both safety and durability
3Ease of manufacture
If conventional purification methods are used, then manufacturing is simpler, but colored impurities cause secondary reactions reducing battery lifetime
Solution Approach 1:
The invention employs activated carbon, a porous material with high surface area, to adsorb colored impurities from ionic liquids. This purification method effectively removes degradation-causing impurities while maintaining a relatively simple manufacturing process, resolving the contradiction between ease of manufacture and battery lifetime
Solution Approach 2:
The invention uses activated carbon as an intermediary substance to facilitate the removal of colored impurities. The carbon acts as a mediator between the ionic liquid and the purification process, enabling effective impurity removal without complex manufacturing steps, thus resolving the contradiction between simplicity and effectiveness
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 purified ionic liquid enhances battery longevity and safety by minimizing secondary reactions and maintaining high ionic conductivity, even at high concentrations, thereby meeting the requirements for lithium-ion batteries.
Implementation Method 1
contacting said initial ionic liquid with activated carbon, to collect a decolorized ionic liquid
Data Source
AI summary
The invention relates to an ionic liquid comprising an anion of formula (I) and at least one onium cation, said ionic liquid having a colour of less than 115 Hazen units on the APHA scale. The invention also relates to a method for purifying an ionic liquid comprising an anion of formula (I) and at least one onium cation.