Fluorinated Ether Electrolyte for High-Voltage Battery Stability
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Solution Overview
Problem
Conventional lithium ion secondary batteries with high potential positive electrodes face performance deterioration due to electrolyte decomposition, leading to significant capacity loss during charge and discharge cycles, and existing additives do not adequately address this issue.
Innovation Solution
A non-aqueous electrolyte comprising a solvent mixture with diethyl carbonate, a lithium salt, a fluorine-containing ether compound with specific alkyl groups, and a boron-based compound, which improves solubility and reduces capacity decrease at high voltages, specifically formulated to include 1,1,2,3,3,3-hexafluoropropyl difluoromethyl ether and 2,2,3,3,4,4,5,5-nonafluoropentyl difluoromethyl ether, with optimized concentrations to enhance battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a positive electrode with high potential (≥4.5V) is used to increase energy density, then the energy density is improved, but the electrolyte decomposes leading to capacity loss
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte by introducing a fluorinated ether compound with specific molecular structure (Formula I) where R1 is a fluorinated alkyl group and R2 is a specific alkyl group. This parameter change in the electrolyte composition enables stable operation at high potentials ≥4.5V without decomposition, resolving the contradiction between high energy density and capacity retention
Solution Approach 2:
The patent creates a composite electrolyte system by combining the fluorinated ether compound (Formula I) with conventional electrolyte solvents and lithium salts. This composite approach integrates the protective properties of the fluorinated compound with the ionic conductivity of conventional electrolytes, achieving both high energy density and capacity retention
2Reliability
If conventional electrolyte additives are used to prevent decomposition, then some protection is provided, but significant capacity decrease still occurs during charge and discharge cycles
Solution Approach 1:
The patent fundamentally changes the additive parameter by using a fluorinated ether compound with specific structural features ( fluorinated alkyl group R1 and specific alkyl group R2) instead of conventional additives. This parameter change provides superior protection against electrolyte decomposition while maintaining high capacity retention during charge-discharge cycles
Solution Approach 2:
The fluorinated ether compound acts as an intermediary substance that mediates between the high-potential positive electrode and the conventional electrolyte. It forms protective interface layers that prevent direct contact and decomposition reactions, thereby protecting the electrolyte while maintaining electrochemical performance
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 electrolyte formulation significantly reduces capacity loss during charge and discharge cycles at high voltages, enabling lithium ion secondary batteries to maintain high energy density over a long period, outperforming conventional batteries in capacity retention rates.
Implementation Method 1
the use of a positive electrode having a high potential leads to a problem in that the battery performance deteriorates due to the decomposition of the electrolyte
Implementation Method 2
a non-aqueous electrolyte comprising a solvent mixture with diethyl carbonate, a lithium salt
Data Source
Figure 1
Figure 2~3
AI summary
An electrolyte contains a non-aqueous solvent, a lithium salt, and a fluorine-containing ether compound represented by the following Formula (I). In the following formula, R1 represents an alkyl group having 3 to 8 carbon atoms; R2 represents an alkyl group having 1 carbon atom; at least 6 carbon atoms among carbon atoms bonded to the alkyl group represented by R1 are substituted with fluorine atoms; and at least one hydrogen atom among hydrogen atoms bonded to the alkyl group represented by R2 is substituted with a fluorine atom.