Lithium Halide Production with Solvent-Mediated Reaction

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Solution Overview

Problem

Existing methods for producing lithium halide compounds, such as lithium bromide and lithium iodide, face challenges in achieving low water content and high reaction efficiency without the need for direct water removal steps, particularly when using conventional pulverization techniques that lead to delayed reactions and poor mass productivity.

Innovation Solution

A method involving the use of solvents that dissolve lithium halides, specifically lithium bromide and lithium iodide, to promote the reaction between lithium sulfide and a halogen molecule without pulverization, ensuring the lithium halide is dissolved in the solvent rather than deposited on the surface of lithium sulfide, thereby enhancing reaction efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional pulverization techniques are used to react lithium sulfide with halogen molecules, then the reaction can proceed, but the reaction is delayed and mass productivity is poor

Engineering Contradiction:
Improvemass productivityVSAvoidreaction time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent introduces a solvent as an intermediary medium to facilitate the reaction between lithium sulfide and halogen molecules. The solvent dissolves the halogen molecules and enables their effective contact with lithium sulfide surface, replacing the conventional pulverization method. This intermediary solvent system accelerates the reaction rate and improves mass productivity without requiring mechanical pulverization.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the physical state and solubility parameters of the reactants by introducing a suitable solvent system. By selecting a solvent in which halogen molecules are soluble but lithium sulfide is insoluble, the reaction conditions are optimized to achieve rapid reaction without pulverization, thereby improving productivity and reducing reaction time.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If lithium sulfide is reacted with halogen molecules without a solvent, then the reaction mixture can be easily handled, but lithium halide deposits on the surface of lithium sulfide and reaction efficiency decreases

Engineering Contradiction:
Improvereaction efficiencyVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The solvent acts as an intermediary that prevents lithium halide deposition on the lithium sulfide surface. By dissolving the halogen molecules and controlling the reaction environment, the solvent ensures continuous exposure of the lithium sulfide surface to reactants, maintaining high reaction efficiency without complicating the overall process.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies local quality by creating a specific microenvironment around the lithium sulfide particles through the solvent. The solvent provides localized dissolution of halogen molecules at the reaction interface, ensuring efficient mass transfer and preventing product deposition, thereby maintaining high reaction efficiency throughout the process.

Inventive Principle:
Principle #3Local quality

3Reliability

If aqueous raw materials are used to produce lithium halide, then the synthesis process is simple, but water content in the product increases and ion conductivity of the solid electrolyte decreases

Engineering Contradiction:
Improveion conductivityVSAvoidsynthesis process simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the solvent system from aqueous to non-aqueous organic solvents. By selecting solvents that do not contain water but in which halogen molecules are soluble, the method produces anhydrous lithium halide with high ion conductivity while maintaining synthesis process simplicity. This parameter change in solvent composition directly addresses both the reliability and ease of manufacture requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The use of non-aqueous organic solvents creates an inert environment that prevents water contamination during the synthesis process. This inert environment ensures that the produced lithium halide remains anhydrous, maintaining high ion conductivity for solid electrolyte applications, while the synthesis process remains simple and straightforward.

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

4Reliability

If water removal steps are implemented in the production process, then water content in lithium halide is reduced, but the production process becomes more complex and time-consuming

Engineering Contradiction:
Improvewater content controlVSAvoidprocess steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by preventing water incorporation at the synthesis stage through the selection of non-aqueous solvents. By designing the synthesis process to inherently produce anhydrous lithium halide without requiring subsequent water removal steps, the method simplifies the overall process while ensuring reliable water content control and high ion conductivity.

Inventive Principle:
Principle #10Preliminary action

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

This approach allows for the industrial production of lithium halides with low water content and high reaction efficiency, improving mass productivity by preventing lithium halide deposition and promoting continuous reaction without the need for solvent removal steps.

Implementation Method 1

the first solvent is a solvent that dissolves a lithium halide containing the same halogen element as the halogen molecule

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

mixing lithium sulfide, a halogen molecule of at least one of bromine and iodine, and a first solvent

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP4159678B1Method for producing lithium halide compound
Publication Date: 2025.10.01 IDEMITSU KOSAN CO LTD
  • EP4159678B1 patent drawingFigure 1~2
  • EP4159678B1 patent drawingFigure 3~4
  • EP4159678B1 patent drawingFigure 5~6

AI summary

The present invention relates to a method for producing a lithium halide compound, capable of industrially advantageously producing a lithium halide compound having a low water content, particularly lithium bromide and lithium iodide, at a high reaction efficiency without accompanying a step of directly removing water, and the method including mixing lithium sulfide, a halogen molecule of at least one of bromine and iodine, and a first solvent; and removing the first solvent, wherein the first solvent is a solvent that dissolves a lithium halide containing the same halogen element as the halogen molecule.