Furodioxin Electrolyte Additive for Lithium-Polysulfide Shuttle Control
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Solution Overview
Problem
Lithium-sulfur secondary batteries face challenges due to lithium polysulfide elution, leading to capacity loss and decreased ionic conductivity, which limits their commercialization and lifespan.
Innovation Solution
A novel saturated furodioxine derivative compound is introduced as an additive in non-aqueous electrolyte compositions for lithium-sulfur batteries, which addresses lithium polysulfide elution and enhances electrode stability and capacity retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional non-aqueous electrolyte composition is used, then the battery can operate, but lithium polysulfide elution occurs causing capacity loss and decreased ionic conductivity
Solution Approach 1:
The saturated furodioxine derivative compound acts as an intermediary substance in the electrolyte that mediates between lithium polysulfide and the electrode. It preferentially reacts with lithium polysulfide to form stable complexes, preventing polysulfide from directly interacting with and degrading the electrode, thereby reducing elution and improving battery lifespan
Solution Approach 2:
The additive compound serves as a consumable component that sacrificially reacts with lithium polysulfide during initial cycles. By being depleted or transformed in the process, it protects the more critical electrode structures from degradation, effectively using a disposable element to preserve the long-term functionality of the battery system
2Quantity of substance
If lithium polysulfide is dissolved in liquid electrolyte, then ionic conduction occurs, but the polysulfide diffuses toward the anode causing capacity loss
Solution Approach 1:
The invention converts the harmful effect of lithium polysulfide solubility (which causes diffusion and capacity loss) into a beneficial effect. The additive exploits the same solubility property to enable the additive itself to dissolve and interact with polysulfide in solution, forming stable complexes that prevent harmful diffusion while maintaining necessary ionic conductivity
Solution Approach 2:
The additive compound serves as a mediator in the electrolyte solution that intercepts lithium polysulfide molecules. It forms intermediate complexes with polysulfide, preventing their direct diffusion to the anode while maintaining the dissolved state necessary for ionic conduction, thus converting potential energy loss into controlled chemical interaction
3Stability of the object's composition
If lithium polysulfide reacts with lithium metal anode, then lithium sulfide is fixed to the surface, but reaction activity decreases and potential characteristics are degraded
Solution Approach 1:
The additive compound performs preliminary anti-action by preferentially reacting with lithium polysulfide before it can reach and react with the lithium metal anode. This pre-reaction forms stable complexes that prevent the harmful direct interaction between polysulfide and anode, maintaining electrode stability while preserving reaction activity through controlled chemistry
Solution Approach 2:
The additive acts as an intermediary that facilitates a controlled reaction pathway. Instead of allowing direct reaction between lithium polysulfide and lithium metal anode (which degrades performance), the additive mediates the interaction, forming stable intermediate complexes that maintain electrode stability without significantly impeding the overall electrochemical reaction activity
4Stability of the object's composition
If lithium sulfide accumulates on the electrode, then the electrode surface is passivated, but electrical conductivity decreases
Solution Approach 1:
The additive compound serves as an intermediary that prevents direct accumulation of lithium sulfide on the electrode surface. It forms soluble complexes with lithium polysulfide intermediates, keeping them in solution rather than allowing them to deposit and passivate the electrode, thus maintaining electrical conductivity while preserving compositional stability
Solution Approach 2:
The additive changes the chemical parameters of the system by introducing new chemical species that alter the solubility and reactivity characteristics of lithium polysulfide. This parameter change prevents the phase transition from dissolved polysulfide to solid lithium sulfide deposit on the electrode, maintaining electrical conductivity while stabilizing electrode composition
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 compound effectively reduces lithium polysulfide elution, improving the stability and capacity retention of lithium-sulfur batteries, thereby extending their lifespan and achieving higher discharge capacity.
Implementation Method 1
Lithium polysulfide (Li2Sx, x=8, 6, 4 or 2) is an intermediate product generated during the electrochemical reaction of a lithium-sulfur secondary battery, and has high solubility in organic liquid electrolyte
Implementation Method 2
Lithium polysulfide dissolved in liquid electrolyte gradually diffuses toward the anode and escapes the electrochemical reaction area of the cathode
Data Source
AI summary
The present invention pertains to a saturated furodioxin derivative compound, and a use thereof as an additive for a secondary battery. More specifically, the present invention pertains to a novel compound and a method for preparing same, an electrolyte additive and a non-aqueous electrolyte composition containing the compound, and a secondary battery (in particular, a lithium-sulfur secondary battery) including the electrolyte composition, wherein the compound has a structure in which a substituent is bonded to a saturated furodioxin backbone. When the compound is contained as an additive in a non-aqueous electrolyte composition for a secondary battery (in a non-aqueous electrolyte composition for a lithium-sulfur secondary battery), the problem that conventional electrolyte compositions have of lithium polysulfide dissolution can be resolved, and high capacity retention rate characteristics can be achieved for various lithium salts.