Organic Thiol Coating for Moisture-Stable Sulfide Solid Electrolytes

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Solution Overview

Problem

Sulfide-containing solid electrolytes are hypersensitive to moisture and air, requiring expensive and cumbersome inert environments for handling, which hampers their practical use and commercialization, and existing stabilization methods compromise ionic conductivity or interfacial stability.

Innovation Solution

A long chain alkyl thiol, such as 1-undecanethiol, is used as an organic coating for sulfide-containing solid electrolytes, providing protection against moisture and air without significantly affecting conductivity, through surface molecular interactions that form a hydrophobic barrier.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If sulfide-containing solid electrolytes are handled in inert gloveboxes with low moisture levels, then chemical stability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvechemical stabilityVSAvoidhandling equipment complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-coating the sulfide-containing solid electrolyte surface with an organic compound before exposure to ambient conditions. This protective coating is applied in advance to prevent moisture and air contact, eliminating the need for complex inert glovebox handling equipment during subsequent processing and assembly operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The organic coating compound serves as an intermediary layer between the sulfide-containing solid electrolyte and the ambient environment. This mediator protects the electrolyte from direct contact with moisture and air, allowing handling in simpler equipment while maintaining chemical stability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If metal oxides are added to sulfide SEs to absorb H2S, then chemical stability is improved, but ionic conductivity decreases

Engineering Contradiction:

Improvechemical stabilityVSAvoidionic conductivity

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies local quality by concentrating the protective function at the surface level through organic coating, rather than distributing metal oxide particles throughout the bulk material. This localized protection preserves the bulk ionic conductivity while providing surface-level chemical stability against moisture and air.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The organic coating acts as an intermediary barrier that prevents moisture and air from reaching the sulfide electrolyte surface, eliminating the need for metal oxide additives that would compromise ionic conductivity. The coating mediates the interaction between the electrolyte and environment without interfering with ion transport.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If sulfide-containing solid electrolytes are exposed to moisture and air, then ease of manufacture is improved, but chemical stability deteriorates

Engineering Contradiction:

Improvemanufacturing easeVSAvoidchemical stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

4Stability of the object's composition

If the concentration of Li-modifier units is reduced in sulfide electrolyte glasses, then chemical stability is improved, but ionic conductivity decreases

Engineering Contradiction:

Improvechemical stabilityVSAvoidionic conductivity

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent applies local quality by concentrating the protective function at the surface level through organic coating, rather than modifying the bulk composition. This allows the bulk material to maintain optimal Li-modifier concentration for high ionic conductivity while the surface coating provides localized chemical stability against moisture and air.

Inventive Principle:

Principle #3Local quality

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 organic coating extends the time sulfide electrolytes can be exposed to ambient conditions, simplifying manufacturing and facilitating commercialization, with improved stability and conductivity retention, offering over 100x improvement in protection time compared to previous methods.

Implementation Method 1

the organic coating is formed on the surface of the sulfide-containing solid state electrolyte material

Methodology Applied

Scientific EffectAdsorption: Adsorption

Implementation Method 2

the organic coating is prepared from a thiol having a hydrophobic chain, which protects the sulfide-containing solid electrolyte material from air and moisture

Methodology Applied

Scientific EffectHydrophobic effect: Hydrophobe

Data Source

PatentEP4700886A1Organic coating for sulfide-containing solid electrolyte material, solid electrolyte, and solid battery comprising same

Publication Date: 2026.02.25 LG ENERGY SOLUTION LTD

Figure 1A~1B
Figure 2A
Figure 2B

AI summary

Disclosed is a coated sulfide-containing solid electrolyte material, as well as a solid electrolyte thereof, and a solid state battery containing a solid electrolyte thereof. According to aspects of the disclosure, the coating is formed on the surface of a sulfide-containing solid electrolyte material, and includes a compound having a thiol with a long hydrophobic tail, e.g., such as l-undecanethiol. The coating may provide protection from air and moisture, for instance, under ambient conditions.