Li-P-S Solid Electrolyte Preparation Without Unstable Sulfide Reagents
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Solution Overview
Problem
Existing methods for preparing Li—P—S products, such as Li7P3S11, require the use of chemically unstable reagents like Li2S and P2S5, which need to be stored in a protected atmosphere, and involve complex processes that are not environmentally friendly.
Innovation Solution
A new method for preparing Li—P—S products involves mixing Li4P2S6, Li2S, and sulfur to form a first mixture, which is then heated in an inert atmosphere under vacuum or H2S flow to produce the Li—P—S product, eliminating the need for exclusive use of Li2S and P2S5 and reducing environmental concerns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Li2S and P2S5 are used as reagents for preparing Li7P3S11, then the product can be obtained, but the reagents are chemically unstable in ambient atmosphere and require protected atmosphere storage
Solution Approach 1:
The patent changes the chemical composition parameters of the reagent system by replacing unstable Li2S and P2S5 with stable LiCl and (NH4)2SO4, which have completely different chemical properties but can still produce the desired Li7P3S11 product through appropriate reaction conditions
Solution Approach 2:
The patent uses commercially available, stable compounds (LiCl and (NH4)2SO4) that can be stored indefinitely in ambient conditions, replacing the need for specialized storage infrastructure required for unstable reagents
2Reliability
If Li2S and P2S5 are used as reagents, then Li7P3S11 can be synthesized, but the process requires working in a protected atmosphere throughout the entire process
Solution Approach 1:
The patent changes the processing conditions by using reagents that are stable in ambient atmosphere, allowing the synthesis to be performed without inert gas protection, thus eliminating the need for complex atmosphere control systems
Solution Approach 2:
The patent extracts and removes the requirement for protected atmosphere from the synthesis process by selecting reagents that do not react with air, thereby simplifying the overall process configuration
3Reliability
If conventional reagents Li2S and P2S5 are used, then the synthesis can proceed, but environmental concerns arise due to chemical instability and potential contamination
Solution Approach 1:
The patent uses stable, environmentally benign reagents (LiCl and (NH4)2SO4) that are safe to handle and dispose of, replacing the hazardous unstable reagents that pose environmental risks
Solution Approach 2:
The patent converts the potential harm of using unstable reagents into a benefit by selecting stable reagents that eliminate contamination risks while still achieving the desired synthesis outcome
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 high Li+ conductivity Li—P—S products like Li7P3S11 without the need for chemically unstable reagents, reducing environmental impact and simplifying the production process.
Implementation Method 1
heating the first mixture in an inert atmosphere, under vacuum or under H2S flow, for a period of time and at a temperature sufficient to produce the Li—P—S product
Data Source
AI summary
The present invention concerns a new method for the preparation of a Li—P—S product, as well as the products obtainable by said methods, and uses thereof especially as solid electrolytes.