Sulfide Solid Electrolyte Amorphization via Temperature Control

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Solution Overview

Problem

Li2S-P2S5-LiI electrolytes with poor ion-conducting characteristics are often manufactured using existing methods, which hinder the production of sulfide solid electrolytes with good ion-conducting properties.

Innovation Solution

Controlling the reaction site temperature during the synthesis of sulfide glass using a raw material composition of (100 - x)(0.75Li2S·0.25P2S5)·xLiI, where 15 ≤ x ≤ 30, to prevent the formation of specific crystalline phases that impede ion conductivity, by ensuring the temperature satisfies the formula y < −2.00x + 1.79 × 10^2, thereby enhancing the ion-conducting characteristics of the sulfide solid electrolyte.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the mechanical milling method is used to manufacture Li2S-P2S5-LiI electrolytes, then the manufacturing process is simple, but the ion-conducting characteristics are poor

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidion-conducting characteristics
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the reaction site temperature during the mechanical milling process. The temperature is maintained below a specific threshold (y < -2.00x + 1.79 × 10^2, where x is LiI content) to prevent crystalline phase formation. This temperature parameter control transforms the conventional mechanical milling method into a process that produces amorphous sulfide glass with superior ion conductivity, resolving the contradiction between manufacturing simplicity and ion-conducting performance.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the reaction site temperature is increased to improve manufacturing efficiency, then the productivity increases, but crystalline phases form that reduce ion conductivity

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidion conductivity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent establishes a quantitative relationship between LiI content (x) and reaction site temperature (y) through the formula y < -2.00x + 1.79 × 10^2. This parameter control strategy allows the process to operate at higher temperatures for improved productivity while maintaining amorphous structure and high ion conductivity. The formula provides a precise temperature ceiling that prevents crystalline phase formation even at elevated temperatures.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If LiI content is increased to improve ion conductivity, then the ion-conducting characteristics improve, but the temperature control range narrows making manufacturing difficult

Engineering Contradiction:
Improveion-conducting characteristicsVSAvoidtemperature control range
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent's temperature control formula y < -2.00x + 1.79 × 10^2 dynamically adjusts the maximum allowable temperature based on LiI content. As LiI content (x) increases to improve ion conductivity, the formula automatically lowers the temperature ceiling (y) to prevent crystallization. This adaptive parameter control maintains ease of manufacture by providing a clear, composition-dependent temperature guideline that ensures amorphous structure formation regardless of LiI content.

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

This method allows for the production of sulfide solid electrolytes with improved ion conductivity by preventing the formation of crystalline phases that cause low ion conductivity, thereby increasing the productivity and reducing manufacturing costs.

Implementation Method 1

amorphizing the raw material after loading

Methodology Applied
Scientific EffectAmorphization: Vitrification

Implementation Method 2

controlling a reaction site temperature in the vessel when sulfide glass is synthesized

Methodology Applied
Scientific EffectTemperature control: Heating

Data Source

PatentEP2940778B1Sulfide-solid-electrolyte manufacturing method
Publication Date: 2022.10.05 TOYOTA JIDOSHA KK
  • EP2940778B1 patent drawingFigure 1
  • EP2940778B1 patent drawingFigure 2
  • EP2940778B1 patent drawingFigure 3

AI summary

A main object of the present invention is to provide a method for manufacturing a sulfide solid electrolyte that enables a sulfide solid electrolyte whose ion-conducting characteristic is easy to be improved, to be manufactured. The present invention is a method for manufacturing a sulfide solid electrolyte including loading a raw material for manufacturing a sulfide solid electrolyte which is mainly composed of a substance represented by the general formula of (100 - x)(0.75Li2S·0.25P2S5)·xLiI (here, 0 &lt; x &lt; 100), into a vessel; and amorphizing the raw material after said loading, wherein a reaction site temperature in the vessel is controlled so that x included in the general formula and the reaction site temperature y [°C] in the vessel in said amorphizing satisfy y &lt; -2.00x + 1.79 x 102.