LGPS Solid Electrolyte Solution Synthesis

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Solution Overview

Problem

Conventional methods for producing LGPS-type solid electrolytes face challenges such as limited scalability and instability due to the use of volatile and decomposable raw materials, making it difficult to achieve stable performance and large-scale production.

Innovation Solution

A method involving the mixing and reaction of Li2S and P2S5 in an organic solvent to form a homogeneous solution, followed by suspension of MS2 (M = Ge, Si, or Sn) and additional Li2S to generate a precipitate, which is then heat-treated to produce a stable LGPS-type solid electrolyte without mechanical milling, using ether-based, ester-based, or nitrile-based solvents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional methods use P2S5 as raw material with mechanical milling and amorphous treatment, then LGPS-type solid electrolyte can be produced, but the process becomes complex and scalability is limited

Engineering Contradiction:
ImprovescalabilityVSAvoidprocess complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention replaces mechanical milling with a chemical solution-based approach. Li2S and P2S5 are dissolved in an organic solvent to form a homogeneous solution, which is then processed through filtration and drying to obtain the electrolyte. This substitution eliminates the need for complex mechanical milling equipment and multiple amorphous treatment steps, directly improving scalability while reducing process complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the physical state parameters of the raw materials by dissolving Li2S and P2S5 in an organic solvent. This transformation from solid-state mechanical processing to solution-based processing allows for easier mixing, filtering, and scaling up of the production process, thereby resolving the contradiction between productivity and device complexity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If P2S5 is used as raw material in conventional methods, then LGPS-type solid electrolyte can be synthesized, but volatility and decomposability of P2S5 cause instability and by-product generation

Engineering Contradiction:
Improveperformance stabilityVSAvoidby-product generation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention uses an organic solvent to dissolve P2S5 and Li2S, creating a controlled chemical environment. The solvent acts as a medium that stabilizes the reactive P2S5 during the reaction process, preventing its volatility and decomposability from causing instability and by-product generation. This effectively creates an inert environment that protects against the harmful properties of P2S5.

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

3Ease of manufacture

If mechanical milling and amorphous treatment are used in conventional production, then LGPS-type solid electrolyte can be obtained, but the process requires complex treatment steps

Engineering Contradiction:
Improveprocess simplicityVSAvoidtreatment steps
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The invention replaces mechanical milling and amorphous treatment with a simple solution-based process. By dissolving the raw materials in an organic solvent and using filtration followed by drying, the complex mechanical treatment steps are eliminated. This substitution significantly simplifies the manufacturing process while maintaining product quality, directly addressing the contradiction between ease of manufacture and device complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If conventional methods are used for producing LGPS-type solid electrolyte, then the electrolyte can be produced at small scale, but mass production is difficult to achieve

Engineering Contradiction:
Improvemass production capabilityVSAvoidperformance consistency
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention changes the production approach from solid-state mechanical processing to solution-based processing. The homogeneous solution formed by dissolving Li2S and P2S5 in an organic solvent ensures uniform distribution of components, which maintains performance consistency during scaling. The subsequent filtration and drying steps are easily scalable operations, enabling mass production while preserving manufacturing precision.

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 enables the production of LGPS-type solid electrolytes with minimal impurities and high ion conductivity, suitable for mass production and application in all-solid-state batteries, overcoming the limitations of previous methods by eliminating the need for mechanical milling and allowing for better atmosphere control.

Implementation Method 1

mixing and reacting Li2S and P2S5 in an organic solvent to obtain a homogeneous solution

Methodology Applied
Scientific EffectDissolution: Solvation

Implementation Method 2

mixing and reacting Li2S and P2S5 in an organic solvent

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Implementation Method 3

suspending at least one MS2 in the homogeneous solution

Methodology Applied
Scientific EffectSuspension: Suspension

Implementation Method 4

adding Li2S thereto to be mixed therewith to obtain a precipitate

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 5

heating and forming the LGPS-type solid electrolyte

Methodology Applied
Scientific EffectHeat treatment: Heat Treatment

Data Source

PatentEP3678149B1Method for producing LGPS-based solid electrolyte
Publication Date: 2023.08.16 MITSUBISHI GAS CHEM CO INC
  • EP3678149B1 patent drawingFigure 1~2
  • EP3678149B1 patent drawingFigure 3~4
  • EP3678149B1 patent drawingFigure 5

AI summary

According to the present invention, a method for producing an LGPS-type solid electrolyte can be provided, the method being characterized by comprising: a solutionization step for preparing a homogeneous solution by mixing and reacting Li2S and P2S5 in an organic solution such that the molar ratio of Li2S/P2S5 is 1.0-1.85; a precipitation step for forming a precipitate by adding, to the homogeneous solution, at least one MS2 (M is selected from the group consisting of Ge, Si, and Sn) and Li2S and then mixing; a drying step for obtaining a precursor by removing the organic solution from the precipitate; and a heating treatment step for obtaining the LGPS-type solid electrolyte by heating the precursor at 200-700°C.