Lithium Sulfide Powder via Inert Spray Drying for Purity Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for synthesizing lithium sulfide face challenges such as poor kinetic control, reliance on expensive raw materials, high processing costs, and environmental concerns, leading to unsuitable conditions for large-scale commercialization, and the drying process affects the purity of the resulting material.

Innovation Solution

A precursor for lithium sulfide with a hollow structure is used, characterized by specific particle size distribution and Raman peak profiles, and controlled drying conditions to produce a high-purity lithium sulfide powder suitable for sulfide-based solid electrolytes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional synthesis methods (high-energy ball milling, wet plasma processing, wet/dry methods) are used to produce lithium sulfide, then lithium sulfide can be obtained, but the process suffers from poor kinetic control, high costs, and environmental concerns

Engineering Contradiction:
Improvekinetic controlVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention changes the chemical parameters of the synthesis process by using lithium sulfate as the starting material instead of traditional lithium metal or hydrogen sulfide. The carbon thermal reduction method transforms the reaction conditions to achieve better kinetic control while simplifying the manufacturing process and reducing environmental impact.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses inexpensive lithium sulfate and carbon as raw materials, replacing expensive and hazardous materials. The carbon source is consumed in the reaction to reduce lithium sulfate to lithium sulfide, providing a cost-effective and environmentally friendly approach.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Ease of manufacture

If carbon thermal reduction method is used to synthesize lithium sulfide, then environmental friendliness and low cost are achieved, but the extraction solution requires complex drying, heat treatment, or crystallization processes to ensure product purity

Engineering Contradiction:
Improveraw material costVSAvoidproduct purity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention performs preliminary action by carefully controlling the drying process parameters before heat treatment. The extraction solution is dried under specific conditions (temperature, time, atmosphere) to prevent impurity formation, ensuring high product purity before subsequent heat treatment steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention uses an inert atmosphere (nitrogen or argon) during the drying and heat treatment processes to prevent oxidation and other unwanted reactions. This inert environment protects the lithium sulfide from reacting with oxygen and maintains high product purity.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Device complexity

If improper drying method is used for the extraction solution, then processing is simplified, but the purity of the resulting dried material decreases

Engineering Contradiction:
Improvedrying process complexityVSAvoiddried material purity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The invention optimizes the drying parameters (temperature, time, atmosphere composition) to achieve the right balance between process simplicity and product purity. By controlling these parameters, high-purity lithium sulfide is obtained without requiring overly complex drying equipment or procedures.

Inventive Principle:
Principle #35Parameter changes

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 method ensures uniform particle size distribution and controlled impurity content, resulting in high-purity lithium sulfide powder suitable for solid-state electrolytes, enhancing the production process and reducing environmental impact.

Implementation Method 1

the carbonthermal reduction method offers an environmentally friendly alternative by avoiding the use of toxic hydrogen sulfide (H 2 S) gas and allowing the use of low-cost lithium sulfate (Li 2 SO 4 )

Methodology Applied
Scientific EffectCarbon thermal reduction: Reduction

Implementation Method 2

the drying method for the extraction solution critically affects the properties of the resulting dried material

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4635910A1Precursor for producing lithium sulfide and lithium sulfide powder
Publication Date: 2025.10.22 POSCO HLDG INC
  • EP4635910A1 patent drawingFigure 1a~1b
  • EP4635910A1 patent drawingFigure 2a~2b
  • EP4635910A1 patent drawingFigure 2c~2d

AI summary

The present invention relates to a method for producing lithium sulfide, the method comprising: mixing a carbon material and a lithium compound to prepare a lithium-carbon compound; filtering a solution obtained by mixing the lithium-carbon compound with a solvent; spray-drying the filtrate in an inert loop structure at a temperature ranging from 110°C to 160°C; and heat-treating the spray-dried product, whereby lithium sulfide having an oxygen content of less than 2.8% can be produced.