Nonaqueous Electrolyte Composition for Lithium Dendrite Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-sulfur batteries experience degradation due to electrolyte decomposition and lithium dendrite formation, leading to reduced charge/discharge efficiency and shortened lifespan, particularly at high temperatures.
Innovation Solution
A nonaqueous electrolyte comprising a heterocyclic compound, ether-based, ester-based, and carbonate-based solvents, and lithium bis(nonafluorobutanesulfonyl)imide (LiNFSI) is used, forming a protective layer on the lithium metal surface to inhibit dendrite formation and enhance stability, with specific solvent and salt concentrations optimized for improved high-temperature performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as negative electrode active material to achieve high energy density, then capacity density and specific energy are improved, but lithium dendrite formation and SEI layer creation occur leading to reduced battery life
Solution Approach 1:
The patent introduces a specific electrolyte composition containing lithium bis(nonafluorobutanesulfonyl)imide salt and heterocyclic compounds as intermediary substances between the lithium metal anode and the battery system. This electrolyte formulation mediates the interaction by forming a stable protective interface that prevents direct harmful reactions between lithium metal and electrolyte components, thereby enabling high energy density to be achieved without the typical penalty of reduced battery life
Solution Approach 2:
The patent modifies the chemical parameters of the electrolyte by using lithium bis(nonafluorobutanesulfonyl)imide salt with specific fluorinated groups and heterocyclic compounds. These parameter changes in the electrolyte composition alter the properties of the SEI layer formed on lithium metal, making it more stable and protective, thus resolving the contradiction between achieving high energy density through lithium metal and maintaining battery life
2Device complexity
If conventional electrolyte composition is used to simplify battery design, then device complexity is reduced, but electrolyte decomposition accelerates at high temperature leading to reduced stability
Solution Approach 1:
The patent employs a composite electrolyte system combining lithium bis(nonafluorobutanesulfonyl)imide salt with specific heterocyclic compounds (such as 3-methyl-1,3-oxathiolane and 2-methylfuran). This composite material approach creates synergistic effects where the combination of components provides enhanced thermal stability and resistance to decomposition at high temperatures, while maintaining a relatively simple overall electrolyte formulation that does not significantly increase device complexity
3Stability of the object's composition
If electrolyte concentration is increased to improve stability, then electrolyte decomposition is reduced, but charge/discharge efficiency decreases due to increased viscosity
Solution Approach 1:
The patent optimizes the concentration parameters of lithium bis(nonafluorobutanesulfonyl)imide salt and heterocyclic compounds in the electrolyte. By carefully controlling these parameters, the electrolyte achieves sufficient stability to resist decomposition while maintaining appropriate viscosity levels. The specific fluorinated structure and heterocyclic components enable this optimization by providing molecular characteristics that balance stability and fluidity, preventing the typical trade-off where increased concentration leads to excessive viscosity and reduced charge/discharge efficiency
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 composition significantly reduces electrolyte decomposition and lithium dendrite formation, enhancing the battery's life characteristics and stability, especially at high temperatures.
Implementation Method 1
lithium metal used as a negative electrode active material easily forms large-area dendrite and reacts with a salt and additive in an electrolyte to form a solid electrolyte interphase (SEI)
Implementation Method 2
The nonaqueous electrolyte significantly reduces electrolyte decomposition and lithium dendrite formation, enhancing the battery's life characteristics and stability
Data Source
Figure 1
AI summary
The present disclosure relates to a nonaqueous electrolyte having improved stability. The nonaqueous electrolyte includes: a first solvent including a heterocyclic compound having at least one double bond or not, and containing at least one of oxygen and sulfur atoms; a second solvent including at least one of an ether-based compound, an ester-based compound, an amide-based compound and a carbonate-based compound; and a first lithium salt, wherein the first lithium salt includes lithium bis(nonafluorobutanesulfonyl)imide, and the lithium bis(nonafluorobutanesulfonyl)imide is present in an amount of 2-5 wt% based on 100 wt% of the total weight of the nonaqueous electrolyte.