Fluorinated Alkenyl Ether Electrolyte for Low-Resistance Li-Ion Cycling
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Solution Overview
Problem
Current lithium-ion secondary batteries face challenges in achieving improved cycle characteristics, reduced internal resistance, and minimized gas generation, particularly when used in applications like automobiles, where high energy density and stability are critical.
Innovation Solution
A compound represented by the formula Rf1—O—Rf2, where Rf1 and Rf2 are C2-C4 fluorinated alkenyl groups, is used as an additive or solvent in electrolytic solutions to form a film on electrodes, enhancing cycle characteristics, reducing resistance, and minimizing gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytic solutions are used, then basic battery function is maintained, but cycle characteristics deteriorate and gas generation increases
Solution Approach 1:
The patent introduces a novel compound with specific molecular structure (formula 1) containing fluorinated alkoxy groups, which changes the chemical parameters of the electrolytic solution. This structural modification enables the formation of stable protective films on electrodes, improving cycle characteristics while suppressing gas generation through altered electrochemical behavior.
Solution Approach 2:
The patent combines the novel compound of formula (1) with conventional electrolyte components (cyclic carbonates, chain carbonates, lithium salts) to create a composite electrolytic solution. This composite approach leverages the stabilizing effect of the fluorinated compound while maintaining the ionic conductivity and solvation properties of conventional electrolytes, achieving both improved cycle life and reduced gas generation.
2Power
If battery energy density is increased, then power output improves, but internal resistance increases and stability deteriorates
Solution Approach 1:
The patent modifies the electrolytic solution's chemical composition by introducing the fluorinated compound of formula (1), which changes the interfacial properties between electrolyte and electrodes. This parameter change reduces internal resistance at the electrode-electrolyte interface, enabling higher power output while maintaining system stability through the formation of protective films that prevent degradation.
3Use of energy by moving object
If operating voltage is increased, then energy density improves, but resistance increases and cycle life deteriorates
Solution Approach 1:
The fluorinated compound of formula (1) performs preliminary action by forming stable protective films on electrode surfaces before high-voltage operation begins. This preliminary film formation prevents direct contact between the high-voltage electrolyte and electrode materials, suppressing resistance increase and degradation reactions that would otherwise limit cycle life at high energy density operating conditions.
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 compound significantly improves the cycle performance, reduces internal resistance, and minimizes gas generation in lithium-ion secondary batteries, leading to better stability and safety, especially under high voltage and temperature conditions.
Implementation Method 1
a compound represented by formula (1), wherein Rf1 and Rf2 are the same as or different from each other and are each a C2-C4 fluorinated alkenyl group, is used as an additive or a solvent for an electrolytic solution. The compound can allow an electrochemical device to have improved cycle characteristics, low resistance, and reduced gas generation
Data Source
AI summary
A compound and composition each capable of allowing an electrochemical device to have improved cycle characteristics, low resistance, and reduced gas generation. Also disclosed is an electrochemical device, a lithium-ion secondary battery, and a module each including the composition as an electrolytic solution. More particularly, the disclosure relates to an electrolytic solution containing a compound represented by the following formula (1):Rf1—O—Rf2 (1)wherein Rf1 and Rf2 are the same as or different from each other and are each a C2-C4 fluorinated alkenyl group.