Lithium Battery Electrolyte Fluorinated Ether High Voltage Stability
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Solution Overview
Problem
Current lithium secondary batteries with organic fluorinated ether compounds lack improved performance in terms of energy density and high-voltage stability, particularly in low-temperature resistance and capacity retention.
Innovation Solution
A lithium secondary battery design incorporating a high-voltage cathode active material with a charge cut-off voltage of 4.2 Volts or greater and an electrolyte containing an organic fluorinated ether compound represented by Formula 1, which allows for reversible lithium ion intercalation and deintercalation, and forms a stable solid electrolyte interface (SEI) membrane on the anode surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional organic fluorinated ether compounds are used in the electrolyte, then the battery can operate at high voltage, but the capacity retention and low-temperature resistance are insufficient
Solution Approach 1:
The patent modifies the molecular structure parameters of the organic fluorinated ether compound by introducing fluorine atoms at specific positions (R1 and R2 groups in Formula 1) and adjusting the carbon chain length (C1-C10), thereby changing the physical and chemical properties of the electrolyte to achieve both high capacity retention and improved low-temperature performance
Solution Approach 2:
The electrolyte is designed as a composite system combining the organic fluorinated ether compound with specific additives (5-10 wt% of compounds containing C=O, C-O-C, or C≡N groups) to create synergistic effects that simultaneously improve capacity retention and low-temperature resistance while maintaining high-voltage stability
2Reliability
If the oxidation potential of the electrolyte is increased to improve high-voltage stability, then the durability under high voltage improves, but the complexity of electrolyte formulation increases
Solution Approach 1:
The patent systematically varies the oxidation potential parameters of the organic fluorinated ether compound by changing the fluorine substitution patterns and carbon chain lengths, establishing structure-activity relationships that enable high-voltage stability (up to 4.5V or higher) while maintaining relatively simple electrolyte formulations with the compound at 70-95 wt%
Solution Approach 2:
The patent uses small amounts (5-10 wt%) of additional functional compounds containing C=O, C-O-C, or C≡N groups as additives to the main organic fluorinated ether compound, achieving enhanced high-voltage stability through partial supplementation rather than complete reformulation of the electrolyte system
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 battery exhibits improved capacity retention, reduced low-temperature resistance, and enhanced lifetime characteristics due to the stable SEI membrane and optimized fluorine positioning in the organic fluorinated ether compound, leading to increased oxidation potential and durability under high voltage.
Implementation Method 1
forms a stable solid electrolyte interface (SEI) membrane on the anode surface
Implementation Method 2
allows for reversible lithium ion intercalation and deintercalation
Data Source
AI summary
A lithium secondary battery including: a cathode including a high-voltage cathode active material; an anode; and an electrolyte disposed between the cathode and the anode, wherein the high-voltage cathode active material has a charge cut-off voltage of about 4.2 Volts or greater with respect to a lithium (Li) counter electrode, and wherein the electrolyte includes an organic fluorinated ether compound represented by Formula 1, an organic solvent, and a lithium salt:R1—O—CFnH2-n—R2 Formula 1wherein, in Formula 1, R1 is a C1-C10 alkyl group, a C3-C10 cycloalkyl group, a C1-C10 fluorinated alkyl group, or a C3-C10 fluorinated cycloalkyl group; R2 is hydrogen, fluorine, a C1-C10 alkyl group, a C3-C10 cycloalkyl group, a C1-C10 fluorinated alkyl group, or a C3-C10 fluorinated cycloalkyl group; and n is 1 or 2.