LGPS Solid Electrolyte Purification Using Sulfur-Containing Solvent
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing Li3PS4-based solid-state electrolytes result in unreacted Li2S and intermediate Li4P2S7 impurities, leading to decreased ionic conductivity and challenging purification, which hinders the development of high-performance all-solid-state lithium ion secondary batteries.
Innovation Solution
A production method involving the use of an organic solvent containing 0.1-1.75% sulfur to remove impurities from Li3PS4 powder, followed by filtration and vacuum drying, to produce an LGPS-based solid-state electrolyte with improved ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional synthesis methods (planetary ball mill with organic solvent) are used to produce Li3PS4, then the production process is simple and productive, but unreacted Li2S and intermediate Li4P2S7 impurities remain, decreasing ionic conductivity
Solution Approach 1:
The patent applies extraction by adding an organic solvent containing sulfur (0.1-1.75 mass%) to the synthesized Li3PS4 powder. This solvent selectively dissolves and removes impurities (unreacted Li2S and intermediate Li4P2S7) from the Li3PS4 powder through filtration, achieving high purity without compromising production efficiency
Solution Approach 2:
The patent uses an organic solvent containing sulfur (such as tetrahydrofuran, acetonitrile, ethyl acetate, or methyl acetate) as an intermediary substance. This mediator selectively interacts with impurities in the Li3PS4 powder, enabling their removal while preserving the Li3PS4 structure and maintaining high ionic conductivity
2Ease of manufacture
If Li2S is used as a solid reactant in synthesis, then the reaction can proceed, but Li2S is difficult to dissolve and separate, leading to impurity contamination
Solution Approach 1:
The patent introduces an organic solvent containing sulfur as an intermediary that selectively dissolves and separates Li2S impurities from Li3PS4. The solvent acts as a mediator that interacts with Li2S to enable its removal through filtration, solving the separation difficulty while maintaining manufacturing ease
Solution Approach 2:
The patent changes the chemical environment by introducing an organic solvent with specific sulfur content (0.1-1.75 mass%). This parameter change enables selective dissolution and separation of Li2S impurities, transforming the separation difficulty into an easy filtration process
3Manufacturing precision
If alcohol is used as a solvent to dissolve Li2S, then Li2S can be dissolved, but the solvent decomposes Li3PS4, making purification difficult
Solution Approach 1:
The patent changes the solvent parameters by selecting organic solvents containing sulfur (tetrahydrofuran, acetonitrile, ethyl acetate, or methyl acetate) with specific sulfur content (0.1-1.75 mass%). These solvents provide the necessary dissolution capability for Li2S while maintaining Li3PS4 stability, avoiding the decomposition problem caused by alcohol solvents
Solution Approach 2:
The patent uses a composite approach by combining an organic solvent base with a specific amount of sulfur (0.1-1.75 mass%). This composite solvent system provides both the dissolution capability for Li2S and the stability protection for Li3PS4, overcoming the limitations of pure alcohol solvents
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 enhances the purity of Li3PS4, enabling the production of LGPS-based solid-state electrolytes with superior ionic conductivity, suitable for mass production and application in all-solid-state batteries.
Implementation Method 1
a step of adding, to the Li3PS4 powder, a solvent in which sulfur is contained in an amount of 0.1-1.75 mass % in an organic solvent to remove impurities in the Li3PS4 powder
Implementation Method 2
the step of removing impurities comprises stirring the Li3PS4 powder and the solvent and filtering the resulting mixture
Implementation Method 3
the step of removing impurities further comprises vacuum drying the filter residue after filtering the mixture
Data Source
AI summary
A method for producing an LGPS-based solid electrolyte includes: preparing Li3PS4 powder, or producing Li3PS4 powder from at least Li2S and P2S5; and removing impurities in the Li3PS4 powder by adding, to the Li3PS4 powder, a solvent in which sulfur is contained in an amount of 0.1-1.75 mass % in an organic solvent.