Argyrodite Sulfide Solid Electrolyte Ionic Conductivity
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Solution Overview
Problem
Current lithium ion batteries with solid electrolytes face challenges in achieving high ionic conductivity and preventing agglomeration during production, particularly when incorporating halogen elements into argyrodite type crystal structures.
Innovation Solution
A sulfide solid electrolyte comprising lithium, phosphorus, sulfur, and one or more halogen elements, with specific molar ratios that satisfy certain formulas, is developed to enhance ionic conductivity and prevent agglomeration, characterized by an argyrodite type crystal structure and a composition that includes an excessive amount of sulfur and halogen, which is achieved through a mechanical stress-induced reaction and heat-treatment process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sulfide solid electrolyte with argyrodite type crystal structure is used to achieve high ionic conductivity, then ionic conductivity is improved, but agglomeration occurs during production
Solution Approach 1:
The patent applies parameter changes by precisely controlling the molar ratios of elements in the sulfide solid electrolyte composition. Specifically, it sets the molar ratio of Li to P (a) between 5.05-7.3, S to P (b) between 3.5-6.0, and X to P (c) between 0.1-2.0, where X is a halogen element. These controlled compositional parameters enable the formation of argyrodite type crystal structure while preventing agglomeration during production, thereby achieving both high ionic conductivity and manufacturing precision.
2Reliability
If halogen elements are incorporated into increase ionic conductivity, then ionic conductivity is improved, but production complexity increases
Solution Approach 1:
The patent incorporates halogen elements (X = F, Cl, Br, or I) into the sulfide solid electrolyte composition with controlled molar ratios (c = X/P between 0.1-2.0). This compositional parameter change enables high ionic conductivity through the argyrodite type crystal structure while maintaining manageable production complexity through defined stoichiometric relationships among elements.
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 sulfide solid electrolyte exhibits high ionic conductivity, exceeding 5.0 mS/cm, and suppresses agglomeration during production, enabling improved performance and productivity in lithium ion batteries.
Implementation Method 1
An argyrodite type crystal structure is a highly stable crystal structure, and some of them have high lithium ion conductivity
Implementation Method 2
which is achieved through a mechanical stress-induced reaction and heat-treatment process
Data Source
AI summary
Aimed at providing a sulfide solid electrolyte comprising an argyrodite type crystal structure, having a high ionic conductivity due to presence of a large amount of a halogen element and is capable of suppressing agglomeration at the time of production. Provided is a sulfide solid electrolyte comprising lithium, phosphorus, sulfur and one or more elements X selected from halogen elements, wherein the sulfide solid electrolyte comprises an argyrodite type crystal structure, and wherein a molar ratio of the lithium to the phosphorus “a (Li/P)”, a molar ratio of the sulfur to the phosphorus “b (S/P)” and a molar ratio of the element X to the phosphorus “c (X/P)” satisfy the following formulas (1) to (3):5.0≤a<7.3 (1)0.70≤a−b<1.0 (2)7.0<a+c≤7.3 (3)provided that b>0 and c>0.