Fluorinated Acetal Electrolytes for High-Voltage Lithium Metal Cells
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Solution Overview
Problem
Existing lithium ion battery electrolytes are incompatible with lithium metal anodes, exhibit low initial Coulombic efficiency, slow ion transport, incompatibility with high-voltage cathodes, and use expensive materials, limiting their performance and scalability.
Innovation Solution
Development of fluorinated acetal molecules, such as di-(2-fluoroethoxy)methane (F1DEM) and bis-(2,2-difluoroethoxy)methane (F2DEM), which are synthesized from common chemical feedstocks and paired with LiFSI salt to form electrolytes that stabilize lithium metal, enhance compatibility with high-voltage cathodes, and improve ion transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium ion battery electrolytes are used, then the battery structure is simple and easy to manufacture, but they are incompatible with lithium metal anodes and exhibit low initial Coulombic efficiency
Solution Approach 1:
The patent modifies the chemical composition parameters of the electrolyte by introducing fluorinated acetal solvents with specific molecular structures (R1-O-CH2-O-R2 where R1 and R2 are hydrocarbon, fluorocarbon, or hydrofluorocarbon chains). This chemical parameter change enables compatibility with lithium metal anodes while maintaining manufacturing feasibility through established electrolyte formulation processes.
Solution Approach 2:
The electrolyte is formulated as a composite system combining fluorinated acetal solvents with lithium salt electrolytes (such as LiFSI, LiTFSI, LiPF6, LiBF4, LiClO4, LiCF3SO3, LiBF2(OX)) at specific concentrations (0.5-3.0 M). This composite approach achieves both lithium metal compatibility and reasonable manufacturing complexity by integrating multiple functional components.
2Productivity
If conventional electrolytes are used, then the device complexity is low, but ion transport is slow and Coulombic efficiency is low
Solution Approach 1:
The patent optimizes physical-chemical parameters of the electrolyte including salt concentration (0.5-3.0 M), solvent molecular structure (fluorinated acetals with specific R1 and R2 groups), and viscosity characteristics. These parameter changes enhance ionic conductivity and ion transport speed while managing the increased compositional complexity through systematic formulation approaches.
3Reliability
If conventional electrolytes are used, then the material cost is low, but they are incompatible with high-voltage cathodes
Solution Approach 1:
The patent modifies the chemical parameters of the electrolyte by incorporating fluorinated acetal solvents with specific molecular structures and fluorine content. These parameter changes provide electrochemical stability and compatibility with high-voltage cathodes (such as LiCoO3, LiNi0.8Co0.1Mn0.1O2, LiFePO4) while controlling material costs through efficient use of fluorinated compounds.
4Reliability
If fluorinated acetal electrolytes are developed to improve performance, then Coulombic efficiency and ion transport improve, but the electrolyte formulation becomes more complex
Solution Approach 1:
The patent systematically varies key parameters including fluorinated acetal solvent structure (different R1 and R2 groups), lithium salt type and concentration (0.5-3.0 M), and additive packages. This structured parameter optimization achieves high Coulombic efficiency (>99%) and fast ion transport while managing formulation complexity through methodical development approaches.
Solution Approach 2:
The electrolyte is designed as a multi-component composite system integrating fluorinated acetal solvents, lithium salts, and optional additives in specific ratios. This composite structure achieves superior Coulombic efficiency and ion transport performance while distributing functional requirements across multiple components, making the overall formulation more manageable despite the enhanced performance demands.
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 new electrolytes achieve fast stabilization of lithium metal, good compatibility with high-voltage cathodes, low cell impedance, and economic viability, enabling higher energy efficiency and scalability.
Implementation Method 1
electrolytes comprising one or more fluorinated acetal molecules as solvents, and one or more salts, wherein the salts are soluble in the solvents
Data Source
AI summary
The present embodiments relate generally to electrolytes for energy storage devices and more particularly to a family of fluorinated acetal molecules as the solvent component for the electrolytes. The present embodiments are directed to electrolytes comprising one or more fluorinated acetal molecules as solvents, and one or more salts, wherein the salts are soluble in the solvents. The electrolytes can be formulated with or without any additional solvents, diluents, or additives. The fluorinated acetal molecules comprise molecular formula of R1-O-CH2-O-R2, wherein R1 and R2 are hydrocarbon, fluorocarbon, or hydrofluorocarbon chains. The products of some embodiments include di(2-fluoroethoxy)methane (F1DEM) and bis(2,2-difluoroethoxy)methane (F2DEM). The obtained electrolytes enable high Coulombic efficiency, quick stabilization of electrodes, good compatibility with high-voltage cathodes, fast ion transport, and low overpotential.