Adjustable-Solvation Electrolyte Solvent for Dendrite-Stable Lithium Batteries
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Solution Overview
Problem
Lithium metal batteries face issues with uncontrollable dendritic lithium growth, irreversibility of lithium layer peeling, and interfacial incompatibility due to excessive free solvents in conventional carbonic acid-based electrolyte solvents, leading to poor cycle life and reduced coulombic efficiency.
Innovation Solution
Development of an electrolyte solvent with adjustable solvation properties, comprising a chemical structure with oxygen, sulfur, selenium, or tellurium, and specific substituents, which forms a strong, uniform, and conductive solid electrolyte interface on the anode surface, inhibiting undesirable cathode electrode interface formation and reducing electrolyte costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional carbonic acid-based electrolyte solvents are used, then lithium-ions can coordinate with carbonate solvent molecules for solvation, but too much free solvent forms solvent-separated ion pairs resulting in poor solid electrolyte interface and serious degradation of battery performance
Solution Approach 1:
The patent changes the chemical parameters of the electrolyte solvent by introducing fluorinated groups and specific ether linkages in Formula (I). These structural modifications alter the solvation properties, reducing free solvent availability while maintaining lithium-ion coordination. The fluorine atoms and ether oxygens provide controlled solvation that prevents solvent-separated ion pair formation, directly resolving the contradiction between solvation capability and harmful free solvent effects.
Solution Approach 2:
The electrolyte solvent employs a composite molecular structure combining fluorinated alkyl groups, ether linkages, and carbonate moieties in Formula (I). This composite design integrates multiple functional elements: fluorine for electrochemical stability and reduced solvation, ether oxygens for lithium coordination, and carbonate groups for ionic conductivity. The synergistic combination achieves both effective solvation and prevention of harmful ion pairing.
2Object-generated harmful factors
If the concentration of lithium salt is increased to reduce free solvent, then solvent-separated ion pair formation is reduced, but this increases electrolyte cost and causes additional problems associated with high electrolyte concentration
Solution Approach 1:
Instead of changing lithium salt concentration, the patent changes the chemical structure of the solvent itself by incorporating fluorinated groups and ether linkages. This structural parameter change reduces the solvent's tendency to form free molecules and ion pairs, achieving the goal of reducing harmful free solvent without increasing salt concentration. Consequently, electrolyte cost remains controlled while effectiveness improves.
3Quantity of substance
If conventional electrolyte solvents are used, then basic solvation function is provided, but uncontrollable dendritic lithium growth and interfacial incompatibility occur leading to poor cycle life
Solution Approach 1:
The patent modifies the solvation parameters by introducing fluorinated groups and ether linkages in Formula (I). These changes create a more controlled solvation shell around lithium ions, preventing uncontrolled dendritic growth. The fluorine atoms provide electrochemical stability while ether oxyens maintain coordination, resulting in uniform lithium deposition and improved interfacial compatibility, thereby extending cycle life while preserving solvation function.
Solution Approach 2:
The modified electrolyte solvent acts as an intermediary between lithium ions and the electrode surfaces. The fluorinated ether-carbonate structure mediates lithium-ion transport and interaction with electrodes, forming a protective interface that prevents direct harmful reactions. This intermediary role enables controlled solvation, uniform lithium deposition, and improved interfacial stability, resolving the contradiction between solvation strength and cycle life.
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 solvent improves battery performance, extends cycle life, and enhances safety during fast charging, maintaining high coulombic efficiency and capacitance retention, applicable to various metal and metal-ion batteries without increasing metal salt concentrations.
Implementation Method 1
the lithium-ions can coordinate with the carbonate solvent molecules for solvation
Data Source
AI summary
The present invention provides an electrolyte solvent with adjustable solvation properties, and through an electrolyte technology, adjusts the anion-rich solvent with favorable solubility, and develops and synthesizes the solvent with weak solvation properties, so that the battery performance can be greatly improved and the solvent can be produced at low cost. The electrolyte technology of the present invention can control the electrochemical battery, taking the lithium battery as an example, the growth pattern of the lithium and the interface control of the positive and negative electrodes, which can help improve the safety of the lithium battery during fast charging, and it can be extended to various electrochemical devices such as metal/metal-ion/metal and metal-ion hybrid batteries.