Fluorinated Battery Electrolytes for Stable Silicon Anode Interfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional battery electrolytes are costly, cumbersome, and inefficient, limiting battery lifetime and performance, particularly when used with silicon-based anodes and high-voltage cathodes like NCM or LCO, due to issues such as unstable solid electrolyte interphase (SEI) layers, volume expansion, and oxidative instability.
Innovation Solution
Development of fluorinated electrolyte formulations that form stable, electronically insulating but ionically conducting SEI layers on silicon anodes and modify cathode surfaces to create stable CEI layers, enhancing electrochemical stability and thermal safety, while using self-supporting composite materials to eliminate metal current collectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte formulations are used with silicon-based anodes, then the battery can operate, but the solid electrolyte interphase (SEI) layers become unstable and battery lifetime is limited
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing fluorinated cyclic carbonate components (such as fluoroethylene carbonate and difluoroethylene carbonate) at specific concentrations (1-30 wt% and 1-20 wt% respectively). This parameter change modifies the electrolyte's interaction with silicon anodes, enabling formation of stable SEI layers that prevent continuous decomposition and maintain battery performance over extended cycling, thereby resolving the contradiction between SEI stability and battery lifetime.
2Quantity of substance
If silicon-based anodes are used to increase capacity, then energy density improves, but volume expansion occurs during cycling
Solution Approach 1:
The patent changes the electrolyte composition parameters by incorporating fluorinated cyclic carbonates that modify the SEI formation process. This creates SEI layers with different physical-chemical properties (enhanced stability and flexibility) that can accommodate silicon's volume expansion during lithium insertion, preventing electrode disintegration while maintaining high capacity, thus resolving the contradiction between capacity and volume stability.
3Quantity of substance
If high-voltage cathodes like NCM or LCO are used to improve energy density, then battery performance increases, but oxidative instability occurs
Solution Approach 1:
The patent changes the electrolyte's chemical composition by adding fluorinated cyclic carbonate components that elevate the electrolyte's oxidation resistance parameters. These components form protective interfaces on high-voltage cathodes (NCM or LCO) that prevent electrolyte decomposition at high potentials, enabling stable operation at 4.2V or higher while maintaining high energy density, thus resolving the contradiction between energy density and oxidative stability.
4Ease of operation
If conventional electrolyte formulations are used, then battery operation is achieved, but flammability and thermal safety issues arise
Solution Approach 1:
The patent changes the electrolyte composition by incorporating fluorinated cyclic carbonate components (fluoroethylene carbonate and difluoroethylene carbonate) that modify the thermal and chemical stability parameters of the electrolyte system. These components form stable protective layers on electrodes and reduce the electrolyte's flammability, enabling safe battery operation at high voltages and temperatures while maintaining operational performance, thus resolving the contradiction between operability and thermal safety.
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
Improves energy density, cycle life, and safety of lithium-ion batteries by stabilizing electrode interfaces, reducing flammability, and increasing thermal stability, thereby overcoming limitations of silicon-based anodes and high-voltage cathodes.
Implementation Method 1
fluorinated electrolyte formulations that form stable, electronically insulating but ionically conducting SEI layers on silicon anodes
Implementation Method 2
modify cathode surfaces to create stable CEI layers
Data Source
AI summary
Electrolytes and electrolyte additives for energy storage devices comprising fluorinated electrolyte additive compounds are disclosed. The energy storage device comprises a first electrode and a second electrode, where one or both of the first electrode and the second electrode is a Si-based electrode, a separator between the first electrode and the second electrode, an electrolyte, and at least one electrolyte additive selected from a linear carbonate, a cyclic carbonate, a linear carboxylic ester, a linear ether, a linear acetate, a sulfone, a linear anhydride, a cyclic anhydride, a phosphate, a phosphite, a phosphorus-containing compound, a phosphazene, a cyclic phosphazene, a nitrogen-containing compound, a silicon-containing compound, a sulfur-containing compound, a Li salt compound, a metal salt compound, fluorine salt compound, or combinations thereof, which may be partially or fully fluorinated and may be optionally substituted.