Lithium Battery Electrolyte Composition for Polysulfide Shuttle Suppression
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Solution Overview
Problem
The commercialization of lithium-sulfur batteries is hindered by issues such as reduced charging/discharging efficiency and shortened lifetime due to side reactions, lithium polysulfide leaching, and dendrite formation, which are not effectively addressed by existing electrolyte solutions.
Innovation Solution
An electrolyte solution for lithium secondary batteries comprising a heterocyclic compound with double bonds and oxygen or sulfur atoms, an ether-based solvent, lithium salt LiFSI, zirconium oxynitrate, and lithium nitrate, optimized to form a protective film and suppress polysulfide shuttling, enhancing coulombic efficiency and lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolyte solutions are used in lithium-sulfur batteries, then the battery can operate, but the lifetime is reduced due to polysulfide shuttling and side reactions
Solution Approach 1:
The patent introduces an intermediary substance (a specific additive compound) that acts as a mediator between the polysulfide and the electrode. This additive forms a protective interface layer that prevents direct harmful interactions while allowing beneficial electrochemical reactions to proceed, thereby suppressing polysulfide shuttling and reducing side reactions without blocking ion transport
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte solution by incorporating a specific additive at optimized concentrations. This parameter change alters the interfacial chemistry between the electrolyte and electrodes, creating a more stable environment that reduces polysulfide dissolution and side reactions, thereby extending battery lifetime
2Productivity
If lithium-sulfur batteries use existing electrolyte compositions, then basic functionality is achieved, but charging/discharging efficiency is reduced
Solution Approach 1:
The patent converts the harmful effect of polysulfide formation into a beneficial outcome by using the polysulfide itself as a precursor for forming a protective solid electrolyte interface (SEI) layer. This SEI layer, formed from controlled polysulfide decomposition, prevents further harmful side reactions while maintaining good ionic conductivity, thus improving charging/discharging efficiency by reducing energy loss
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 significantly improves the capacity and lifetime of lithium secondary batteries by reducing side reactions and polysulfide migration, thereby increasing the coulombic efficiency and overall performance.
Implementation Method 1
optimized to form a protective film and suppress polysulfide shuttling
Implementation Method 2
the reduction reaction of sulfur and the oxidation reaction of lithium metal take place during discharging
Implementation Method 3
the reduction reaction of sulfur and the oxidation reaction of lithium metal take place during discharging
Implementation Method 4
since polysulfide leached from the positive electrode has high solubility in the organic electrolyte solution
Implementation Method 5
it can undesirably move toward the negative electrode (PS shuttling) through the electrolyte solution
Data Source
AI summary
An electrolyte solution for a lithium secondary battery and a lithium secondary battery comprising the same are provided. The electrolyte solution comprises a first solvent comprising a heterocyclic compound containing one or more double bonds and any one of an oxygen atom or a sulfur atom; a second solvent comprising at least one of an ether-based compound, an ester-based compound, an amide-based compound, or a carbonate-based compound; a lithium salt; zirconium oxynitrate; and lithium nitrate.