Electrolyte Anion Composition for Dense Lithium Metal SEI
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Solution Overview
Problem
Conventional batteries with carbon-based negative electrodes have low energy density, while lithium metal-based batteries offer high energy density but suffer from shorter cycle life due to rapid electrolyte decomposition and SEI layer degradation.
Innovation Solution
An electrolyte solution containing a specific anion represented by Formula (I), where X is N, B, P, Al, Si, S, or Se, with R1 and R2 groups forming cyclic structures, enhances the formation of a high-quality SEI layer on the anode surface, reducing decomposition and extending the battery's cycle life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as negative electrode to achieve high energy density, then energy density is improved, but cycle life deteriorates due to rapid electrolyte decomposition and SEI layer degradation
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a specific cyclic carboxylate additive (Formula I) with defined structural parameters (X=N, B, P, Al, Si, S, or Se; specific a and b values). This parameter change in electrolyte composition modifies the SEI layer formation characteristics, enabling dense metal deposition and reducing electrolyte decomposition, thereby extending cycle life while maintaining high energy density with lithium metal negative electrodes
Solution Approach 2:
The cyclic carboxylate compound acts as an intermediary substance that mediates between the lithium metal negative electrode and the electrolyte. It preferentially decomposes to form a stable SEI layer that protects the lithium metal from direct contact with the electrolyte, reducing harmful side reactions and electrolyte consumption while enabling stable long-term cycling
2Use of energy by moving object
If conventional electrolyte is used with lithium metal negative electrode, then high energy density is achieved, but electrolyte decomposition increases leading to shorter cycle life
Solution Approach 1:
The cyclic carboxylate additive performs preliminary action by decomposing first during initial charging cycles to form a protective SEI layer on the lithium metal surface. This preliminary decomposition prevents subsequent electrolyte decomposition, reducing electrolyte consumption over time while maintaining the high energy density enabled by lithium metal electrodes
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 solution improves cycle performance by inducing dense metal deposition and reducing electrolyte consumption, leading to enhanced stability and extended battery life.
Implementation Method 1
the first anion can form a high-quality SEI layer on an anode surface, thereby inducing dense metal deposition
Implementation Method 2
can further reduce the decomposition-induced consumption of the first anion
Data Source
Figure 1~3
Figure 4~6
AI summary
Provided in this application are an electrolyte solution, a battery cell, a battery, and a power consuming apparatus. The electrolyte solution includes a first anion represented by Formula (I), where X, a, b, R1, and R2 are respectively as defined herein.