Ether Electrolyte Structure for High-Voltage Lithium Metal Batteries
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Solution Overview
Problem
Batteries using lithium metal as a negative electrode have high energy density but suffer from short cycle life due to oxidative decomposition of conventional ether solvents, leading to radical generation and poor stability at high voltages.
Innovation Solution
An electrolyte comprising an ether solvent with a molecular structure where the α-carbon atom in the ether-oxygen bond does not have a hydrogen atom bonded to it, enhancing oxidation resistance and promoting the formation of a fluorine-rich solid electrolyte interface film, thereby improving cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional ether solvents are used in batteries with lithium metal negative electrodes, then high energy density is achieved, but cycle life is short due to oxidative decomposition
Solution Approach 1:
The patent changes the chemical structure parameter of the ether solvent by removing hydrogen atoms from the α-carbon position. This structural modification increases the oxidation potential of the solvent, making it resistant to oxidative decomposition at high voltages while maintaining its ability to dissolve electrolytes and support ion transport, thus preserving energy density while extending cycle life
Solution Approach 2:
The patent creates a composite electrolyte system combining fluorinated ether solvents with specific electrolyte salts. The fluorinated ether solvent acts as a stable base that resists oxidation, while the electrolyte salt provides ionic conductivity. This composite approach allows the system to simultaneously achieve high energy density and long cycle life by separating the functions of energy storage and electrochemical stability
2Object-generated harmful factors
If ether solvents undergo oxidative dehydrogenation at the α-carbon atom, then radical generation occurs, but oxidation resistance is reduced
Solution Approach 1:
The patent extracts the problematic hydrogen atoms from the α-carbon position of the ether solvent molecule. By removing these hydrogen atoms through fluorine substitution or other group replacement, the patent eliminates the source of radical generation through oxidative dehydrogenation, thereby preventing harmful radical formation while enhancing oxidation resistance
Solution Approach 2:
The patent converts the potentially harmful effect of α-carbon oxidation into a beneficial outcome by replacing hydrogen with fluorine or other stable groups. This modification prevents the formation of free radicals that would otherwise lead to solvent decomposition, while the fluorine atoms themselves contribute to forming a stable solid electrolyte interface film that further protects the system
3Quantity of substance
If the α-carbon atom has hydrogen atoms bonded to it, then solvation energy is maintained, but stability at high voltage is poor
Solution Approach 1:
The patent applies local quality modification by selectively replacing hydrogen atoms only at the α-carbon position adjacent to the ether oxygen, while leaving other parts of the molecule unchanged. This localized modification maintains the overall solvation capability of the ether solvent through its oxygen atom, while specifically addressing the high-voltage instability issue at the vulnerable α-carbon position
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 improves ionic conductivity and reduces radical generation, resulting in longer cycle life and higher stability for batteries under high voltage conditions.
Implementation Method 1
the ether solvent has a molecular structure in which the α-carbon atom directly bonded to an oxygen atom in an ether-oxygen bond function group does not have a hydrogen atom directly bonded to the α-carbon atom, thereby improving the oxidation resistance of the ether solvent and reducing the generation of radicals after oxidative dehydrogenation of the α-carbon atom
Implementation Method 2
The electrolyte improves ionic conductivity, resulting in longer cycle life and higher stability for batteries under high voltage conditions
Implementation Method 3
the group bonded to the α-carbon atom can also lower the solvation energy, thereby promoting the decomposition of the anion portion of the electrolytic salt to participate in the formation of the solid electrolyte interface film
Data Source
AI summary
Provided are an electrolyte, a battery, and an electrical device, the electrolyte comprises a solvent and an electrolytic salt dissolved in the solvent, the solvent comprises a first solvent comprising an ether solvent, and the ether solvent has a molecular structure in which the α-carbon atom directly bonded to an oxygen atom in an ether-oxygen bond function group does not have a hydrogen atom directly bonded to the α-carbon atom.