Ionic Liquid Electrolyte for Corrosion-Resistant Electrochemical Cells
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Solution Overview
Problem
Conventional electrochemical cells face issues with safety, eco-friendliness, and durability due to the instability of nonionic organic compounds and hexafluorophosphate anions, leading to decomposition reactions and corrosion of cell components.
Innovation Solution
The electrochemical cell employs an electrolyte with at least 80% ionic liquid and less than 1% nonionic organic compounds, using AlF3 protective layers on current collectors and LiFSI as a conducting salt to enhance stability and safety, along with specific anions and cations in the ionic liquid to maintain low viscosity and high conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nonionic organic compounds are used as solvent or additive in the electrolyte, then the electrochemical cell can operate, but decomposition reactions occur leading to capacity losses and reduced durability
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by using ionic liquids (at least 80 wt%) instead of conventional nonionic organic compounds as the main solvent. This parameter change eliminates decomposition reactions and capacity losses while maintaining operational reliability.
Solution Approach 2:
The patent extracts and removes harmful nonionic organic compounds from the electrolyte composition, replacing them with stable ionic liquids. This extraction eliminates the source of decomposition reactions and improves both reliability and stability simultaneously.
2Ease of operation
If conventional electrolytes with nonionic organic compounds are used, then the cell can function, but safety issues arise due to flammability and thermal instability
Solution Approach 1:
The patent creates an inert chemical environment by using ionic liquids as the electrolyte solvent. Ionic liquids provide inherent fire suppression and thermal stability, eliminating flammability hazards while maintaining full cell functionality for energy storage and delivery.
Solution Approach 2:
The patent employs a composite electrolyte system combining ionic liquids with specific conducting salts (LiPF6, LiBF4, LiCF3SO3) to achieve both functional performance and safety. The composite nature provides enhanced thermal stability and fire resistance compared to conventional single-component electrolytes.
3Reliability
If hexafluorophosphate anions (PF6-) are used in the electrolyte, then conducting salt functionality is achieved, but corrosion of cell components and release of toxic substances occur
Solution Approach 1:
The patent applies local quality improvement by specifically selecting conducting salts with alternative anions (BF4-, CF3SO3-) that provide the necessary ionic conductivity without the corrosive and toxic properties of PF6-. This localized chemical substitution eliminates harmful effects while maintaining electrolyte functionality.
4Stability of the object's composition
If ionic liquid is used as the main solvent in the electrolyte (at least 80 wt%), then stability and safety are significantly improved, but viscosity may increase affecting conductivity
Solution Approach 1:
The patent uses a composite electrolyte formulation combining ionic liquids with conducting salts to optimize the balance between stability and conductivity. The composite system maintains the high stability benefits of ionic liquids while the conducting salt component ensures adequate ionic conductivity for energy storage and delivery.
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 solution significantly improves the safety, eco-friendliness, and durability of the electrochemical cell by reducing decomposition reactions, minimizing toxic by-products, and enhancing chemical and thermal stability.
Implementation Method 1
Ionic liquids, in contrast to nonionic organic compounds, are characterized by much lower flammability, much lower vapor pressures, and a much greater thermal stability.
Implementation Method 2
The electrolyte includes an ionic liquid as the solvent, the ionic liquid is present in an amount of at least 80 percent by weight of the total electrolyte
Implementation Method 3
As used herein, 'discharge operation' refers to the conversion of the chemical energy stored in the electrochemical cell into electrical energy which can then be supplied to a consumer.
Data Source
AI summary
An electrochemical cell includes a negative electrode, a positive electrode, an aluminum current collector that is connected to the positive electrode in an electrically conductive manner, and an electrolyte. The electrolyte includes non-ionic organic compounds present in an amount of less than 1.0 wt % of the total electrolyte, and an ionic liquid as a solvent. The ionic liquid is present in the electrolyte in an amount of at least 80 wt % of all electrolytes. In addition, the ionic liquid includes a cation of the formula:and an anion of the formula:Furthermore, the ionic liquid includes a conducting salt containing:The electrolyte has less than 0.5 wt % of PF6−. The aluminum current collector is provided with a protective layer comprising AlF3.