Argyrodite Solid Electrolyte for Lithium-Sulfur Batteries

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Solution Overview

Problem

Lithium-ion batteries face limitations in capacity and stability due to issues such as low ionic conductivity, sensitivity to moisture and air, and instability with liquid organic electrolyte solutions in lithium sulfur batteries.

Innovation Solution

Development of argyrodite-type crystal structure compounds like Li10FeP2S12, which exhibit high ionic conductivity and stability, used in electrochemical cells as solid electrolytes or protective layers to enhance battery performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sulfide materials are used as lithium-ion conductors, then ionic conductivity is improved, but stability against liquid organic electrolyte solutions and metallic lithium deteriorates

Engineering Contradiction:
Improveionic conductivityVSAvoidstability against liquid organic electrolyte solutions
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent employs composite materials by combining sulfide-based solid electrolyte with protective coating layers (such as aluminum oxide, aluminum nitride, or other stable compounds) to create a multi-layer structure. This composite approach allows the inner sulfide layer to provide high ionic conductivity while the outer protective layer provides chemical stability against liquid organic electrolyte solutions and metallic lithium, thus resolving the contradiction between conductivity and stability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces an intermediary protective layer between the sulfide solid electrolyte and the liquid organic electrolyte solution or metallic lithium. This intermediary layer acts as a barrier that prevents direct harmful interactions while allowing lithium ion transport, thereby maintaining both high ionic conductivity and chemical stability simultaneously.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If sulfide materials are used as lithium-ion conductors, then ionic conductivity is improved, but sensitivity to moisture and air increases

Engineering Contradiction:
Improveionic conductivityVSAvoidsensitivity to moisture and air
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent creates a composite structure where the sulfide solid electrolyte is combined with moisture and air-stable protective materials. The protective outer layer provides resistance to environmental factors while the inner sulfide layer maintains high ionic conductivity, thus resolving the contradiction between conductivity and environmental stability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces an intermediary protective coating between the sulfide solid electrolyte and the external environment (moisture and air). This intermediary layer prevents direct contact and harmful reactions with environmental factors while allowing the sulfide layer to function with high ionic conductivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If lithium sulfur batteries are used to improve capacity, then energy density is improved, but stability and lifespan deteriorate

Engineering Contradiction:
ImprovecapacityVSAvoidstability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent employs composite materials by integrating sulfide-based solid electrolyte with protective coating layers to create a stable electrode structure. This composite approach allows lithium sulfur batteries to achieve high capacity while the protective layers prevent degradation reactions, thus resolving the contradiction between capacity and stability/lifespan.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces an intermediary protective layer between the lithium sulfur battery components and the electrolyte. This intermediary layer prevents harmful side reactions that would otherwise reduce stability and lifespan, while allowing the high-capacity lithium sulfur chemistry to function effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 argyrodite-type compounds improve the stability and ionic conductivity of lithium-ion batteries, reducing chemical reactions and enhancing safety, while allowing for higher capacity and longer battery life.

Implementation Method 1

improve the stability and ionic conductivity of lithium-ion batteries

Methodology Applied
Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentEP3407412B1Ionically conductive compounds and related uses
Publication Date: 2021.04.14 BASF SE
  • EP3407412B1 patent drawingFigure 1A~1C
  • EP3407412B1 patent drawingFigure 1D~1E
  • EP3407412B1 patent drawingFigure 2A

AI summary

Articles, compositions, and methods involving ionically conductive compounds are provided. In some embodiments, the ionically conductive compounds are useful for electrochemical cells. The disclosed ionically conductive compounds may be incorporated into an electrochemical cell (e.g., a lithium-sulfur electrochemical cell, a lithium-ion electrochemical cell, an intercalated-cathode based electrochemical cell) as, for example, a protective layer for an electrode, a solid electrolyte layer, and/or any other appropriate component within the electrochemical cell. In certain embodiments, electrode structures and/or methods for making electrode structures including a layer comprising an ionically conductive compound described herein are provided.