3M1P-Modified Sulfide Electrolyte for Higher Critical Current Density
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Solution Overview
Problem
Conventional solid-state lithium batteries face challenges with unstable interfacial compatibility between the solid electrolyte and lithium metal, leading to dendrite formation, short circuits, and rapid failure, while also requiring high operating pressures.
Innovation Solution
Incorporating sodium 3-mercapto-1-propanesulfonate (3M1P) as an additive to the sulfide-based solid electrolyte, creating a composite electrolyte that enhances lithium ion conductivity and facilitates a stable interface with lithium metal, allowing for low-pressure operation and improved cycling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid electrolyte is used in an all-solid-state lithium metal battery, then safety is improved and energy density is increased, but interfacial instability between the solid electrolyte and lithium metal occurs, leading to dendrite formation and short circuits
Solution Approach 1:
The patent introduces an interfacial modification layer composed of Li3PO4 and organic additives between the solid electrolyte and lithium metal. This intermediary layer acts as a mediator that prevents direct contact and harmful reactions between the solid electrolyte and lithium metal, while still allowing lithium ion transport. The layer stabilizes the interface and prevents dendrite formation, resolving the interfacial instability problem while maintaining the safety benefits of solid electrolytes.
Solution Approach 2:
The patent creates a composite interfacial structure combining inorganic Li3PO4 with organic additives (such as fluoroethylene carbonate and lithium bis(fluorosulfonyl)imide). This composite material approach leverages the advantages of both components: the inorganic Li3PO4 provides structural stability and ion conductivity, while the organic additives enhance interfacial compatibility and suppress side reactions. The composite nature of the modification layer effectively stabilizes the interface between solid electrolyte and lithium metal.
2Temperature
If conventional solid electrolytes are used, then thermal stability is improved, but critical current density is low and operating pressure must be high
Solution Approach 1:
The patent modifies the physical and chemical parameters of the solid electrolyte interface through the introduction of Li3PO4 and organic additives. The modification layer changes the interfacial energy, surface morphology, and chemical composition, which collectively improve the critical current density. The organic additives specifically tune the interfacial properties to enable higher current densities while maintaining thermal stability, effectively decoupling these two previously conflicting parameters.
3Stability of the object's composition
If high operating pressure is applied to maintain contact between solid electrolyte and electrodes, then interfacial contact is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies preliminary action by pre-modifying the solid electrolyte surface with Li3PO4 and organic additives before battery assembly. This pre-treatment creates a stable, compliant interfacial layer that maintains good contact between the solid electrolyte and electrodes during cycling without requiring high external pressure. The preliminary modification of the interface eliminates the need for continuous high-pressure application, simplifying the device structure and reducing manufacturing complexity.
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 modified electrolyte achieves a significant increase in critical current density and extends battery life, enabling stable cycling with high-capacity retention and reduced operating pressure, thus addressing the limitations of existing solid-state batteries.
Implementation Method 1
Incorporating sodium 3-mercapto-1-propanesulfonate (3M1P) as an additive to the sulfide-based solid electrolyte, creating a composite electrolyte that enhances lithium ion conductivity and facilitates a stable interface with lithium metal
Data Source
AI summary
Solid electrolyte compositions and solid-state batteries are disclosed, which comprise a solid electrolyte layer including a sulfide-containing solid-state electrolyte material and a compound of Chemical Formula 1. The sulfide-containing solid-state electrolyte material includes but is not limited to Li6PS5Cl (“LPSC”), an LPS-based glass or glass ceramic of formula xLi2S·yP2S5, wherein x+y=1, or an argyrodite-based sulfide-based solid electrolyte or formula Li6PS5X, wherein X=Cl, Br, or I) or Li6−yPS5−yCl1+y, where y is <1. In some aspects, the compound of Chemical Formula 1 is sodium 3-mercapto-1-propanesulfonate (3M1P).