Silicone Epoxy Ether Electrolyte for Safe Li-Ion Batteries
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Solution Overview
Problem
Lithium ion batteries using alkyl carbonate-based electrolytes are unsafe due to flammability and have low ionic conductivity, limiting their power density and practical application, while existing silicone polyether electrolytes do not meet the required ionic conductivity threshold for high power density.
Innovation Solution
Development of silicone epoxy ether compositions with epoxy functionality as electrolyte solvents, which increase the solubility of lithium salts like LiPF6 and enhance ionic conductivity by scavenging water and HF, leading to higher ionic conductivities and improved battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If alkyl carbonate-based electrolytes are used in lithium ion batteries, then ionic conductivity is achieved (10^-3 S/cm), but flammability and safety issues arise
Solution Approach 1:
The patent employs composite electrolyte systems combining silicone polyether base stocks with lithium salts (LiPF6, LiBF4, LiClO4) and additive packages. This composite approach achieves both safety (non-flammability of silicone polyether) and ionic conductivity (through optimized salt concentration and additive selection), resolving the contradiction between safety and harmful factors.
2Reliability
If silicone polyether electrolytes are used to improve safety, then flammability is reduced, but ionic conductivity becomes insufficient (less than 10^-3 S/cm)
Solution Approach 1:
The patent systematically optimizes multiple parameters including lithium salt concentration (0.5-2.0 M), molecular weight of silicone polyether (200-2000 g/mol), and additive concentrations to achieve ionic conductivity greater than 10^-3 S/cm while maintaining safety. This parameter optimization resolves the contradiction between safety and power.
Solution Approach 2:
The patent introduces additive packages including cyclic carbonates (EC, PC) and chain carbonates (DMC, DEC) as intermediary substances that enhance ionic conductivity of the silicone polyether electrolyte. These additives act as mediators that improve power output while the silicone polyether base maintains safety, resolving the contradiction between safety and ionic conductivity.
3Power
If polyethylene oxide (PEO) is used as electrolyte, then ionic conductivity improves (10^-6 S/cm), but it is still insufficient for high power density applications
Solution Approach 1:
The patent achieves ionic conductivity greater than 10^-3 S/cm (exceeding PEO's 10^-6 S/cm) through optimized silicone polyether molecular weight (200-2000 g/mol), lithium salt concentration (0.5-2.0 M), and temperature control (20-60°C). This enhanced ionic conductivity enables high power density applications, resolving the contradiction between ionic conductivity and productivity.
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 silicone epoxy ether compositions achieve ionic conductivities greater than 10^-3 S/cm at room temperature, enhancing the solubility of lithium salts and improving the cycle life and shelf life of lithium ion batteries.
Implementation Method 1
enhance ionic conductivity by scavenging water and HF
Implementation Method 2
increase the solubility of lithium salts like LiPF6 and enhance ionic conductivity
Data Source
AI summary
The present invention relates to silicone epoxy compositions, methods for making same and uses therefore. In one embodiment, the silicone epoxy ether compositions of the present invention are silane epoxy polyethers that contain at least one epoxy functionality. In another embodiment, the silicone epoxy ether compositions of the present invention are siloxane epoxy polyethers that contain at least one epoxy functionality. In still another embodiment, the present invention relates to silicone epoxy polyether compositions that are suitable for use as an electrolyte solvent in a lithium-based battery, an electrochemical super-capacitors or any other electrochemical device.