Lithium Metal Battery Electrolyte With Sultam Additive for Dendrite Control
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Solution Overview
Problem
Lithium metal batteries face challenges with lithium dendrite formation, which can lead to short circuits and reduced cycle life due to the high reactivity of metallic lithium with electrolytes, limiting their development and performance.
Innovation Solution
An electrolytic solution containing a lithium salt, organic solvent, and a sultam compound additive that forms a sulfur-containing inorganic acid salt and an electrolyte interface film, improving the surface properties of the lithium metal electrode and suppressing dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal is used as negative electrode material, then theoretical specific capacity is significantly improved (3860 mAh/g), but lithium dendrites form during cycles causing short circuits and safety issues
Solution Approach 1:
The patent introduces a sultam compound as an intermediary substance in the electrolyte that mediates between lithium metal and the electrolyte system. This compound reacts with trace water to generate SO2 in situ, which then reacts with lithium metal to form a protective interface layer, preventing direct harmful interactions while maintaining electrochemical functionality
Solution Approach 2:
The sultam compound performs preliminary action by proactively generating SO2 through reaction with trace water before lithium dendrites can form. This pre-established protective mechanism creates a stable interface layer in advance, preventing subsequent dendrite growth and short circuiting
2Quantity of substance
If lithium metal is used as negative electrode material, then theoretical specific capacity is significantly improved (3860 mAh/g), but cycle life is reduced due to continuous SEI film restructuring
Solution Approach 1:
The patent converts the harmful trace water in the system into a beneficial substance. The sultam compound reacts with trace water to generate SO2, which then forms a stable protective interface layer on lithium metal. This transforms the harmful moisture into a protective mechanism that extends cycle life
Solution Approach 2:
The patent changes the chemical composition parameters of the interface layer by introducing sulfur-containing compounds. The SO2 generated from sultam compound reaction alters the interface chemistry, creating a stable SEI film with different properties that prevents continuous restructuring and extends battery cycling
3Reliability
If conventional electrolyte additives are used, then SEI film formation occurs, but lithium dendrites still penetrate the separator causing short circuits
Solution Approach 1:
The patent creates a composite interface layer combining organic and inorganic components. The sultam compound generates SO2 that reacts with lithium to form lithium sulfite and other sulfur-containing inorganic acid salts, creating a composite protective layer that is more effective at blocking dendrites than conventional organic additives alone
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 solution enhances the cycle performance and energy density of lithium metal batteries by reducing resistance and side reactions, stabilizing the electrolyte interface, and preventing excessive dendrite formation.
Implementation Method 1
The sultam compound additive added in this application can generate SO2 gas in situ when encountering trace moisture in a battery system. Then an in situ micro reaction occurs between SO2 and a lithium metal negative electrode to form a sulfur-containing inorganic acid salt
Implementation Method 2
The sultam compound used as an additive in the electrolytic solution according to this application contains a sulfonyl group, and can form an electrolyte interface film on surfaces of both the positive electrode and the negative electrode
Data Source
AI summary
This application provides an electrolytic solution and a lithium metal battery containing the electrolytic solution. The electrolytic solution includes a lithium salt, an organic solvent, and an additive. The additive includes a sultam compound represented by Structural Formula I. R is selected from substituted or unsubstituted C1 to C10 hydrocarbyls, where a substituent is selected from a phenyl, C1 to C6 alkyls, or C1 to C6 alkenyls. X is a sulfur atom or a phosphorus atom. R1 and R2 each are independently selected from an oxygen atom, a fluorine atom, a chlorine atom, a bromine atom, and substituted or unsubstituted C1 to C10 hydrocarbyls. Both R1 and R2 are not oxygen atoms concurrently.