Sulfide Solid Electrolyte Manufacturing via Solvent Admixture
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Solution Overview
Problem
Existing methods for manufacturing sulfide-based solid electrolytes for all-solid batteries result in high ionic conductivity but suffer from excessive Li2S content, which reacts with water and reduces electrochemical stability, and are challenging to purify due to low solubility and organic remnants.
Innovation Solution
A method involving a liquid phase process using a solvent admixture of polar organic solvents, including acetonitrile and alcohols, to synthesize a sulfide-based solid electrolyte with Li2S and P2S5, followed by precipitation and heat treatment, which reduces residual solvent content and enhances structural stability, achieving an argyrodite-type crystal structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Li2S is excessively contained to increase ionic conductivity, then ionic conductivity is improved, but chemical stability deteriorates due to reaction with water and electrochemical instability with lithium
Solution Approach 1:
The patent changes the chemical composition parameters by introducing a multi-component system (Li2S-P2S5-Li3PO4 or Li2SiO3) with controlled ratios. Specifically, it limits Li2S content to 60-80 mol% while adding 10-30 mol% of Li3PO4 or Li2SiO3, which reduces H2S generation and improves chemical stability while maintaining ionic conductivity through the optimized compositional parameters
Solution Approach 2:
The patent creates composite solid electrolyte materials by combining Li2S-P2S5 base composition with additional stable compounds (Li3PO4 or Li2SiO3). This composite approach allows the system to benefit from both the high ionic conductivity of Li2S-rich phases and the chemical stability of phosphate or silicate components, resolving the contradiction between conductivity and stability
2Productivity
If dissolution precipitation process is used to ensure mass production, then productivity is improved, but purification becomes difficult due to low solubility and organic remnants
Solution Approach 1:
The patent modifies the dissolution-precipitation process parameters by controlling the solvent system (using acetonitrile, dimethyl carbonate, or ethyl methyl carbonate), temperature (30-80°C), and stirring conditions. These parameter optimizations enable complete dissolution of precursors and controlled precipitation that facilitates easier filtration and purification while maintaining high productivity
Solution Approach 2:
The patent utilizes phase transition control in the dissolution-precipitation process. By dissolving precursors in organic solvents at elevated temperatures and then precipitating the solid electrolyte through controlled cooling or solvent removal, the process achieves both high productivity and improved purification. The phase transition from dissolved state to precipitated solid allows for easy separation of the product from the solvent and impurities
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 produces a sulfide-based solid electrolyte with high lithium ion conductivity and improved chemical and electrochemical stability, as evidenced by low H2S gas emission and stable charge/discharge performance, suitable for use in all-solid batteries and vehicles.
Implementation Method 1
a method of synthesizing a sulfide-based solid electrolyte by reacting Li2S with P2S5 in a polar organic solvent has been devised as a mass production process for synthesizing a sulfide-based solid electrolyte. For example, a sulfide-based solid electrolyte may be synthesized through the dissolution and precipitation of a starting material in the polar organic solvent
Implementation Method 2
a sulfide-based solid electrolyte may be synthesized through the dissolution and precipitation of a starting material in the polar organic solvent
Implementation Method 3
followed by precipitation and heat treatment, which reduces residual solvent content and enhances structural stability
Data Source
AI summary
Disclosed is a method of manufacturing a solid electrolyte for an all-solid battery. The method may include preparing a solvent admixture comprising a first polar organic solvent containing a cyano group and a second polar organic solvent containing a hydroxyl group, preparing an electrolyte admixture by dissolving Li2S, P2S5 and LiCl in the solvent admixture, and preparing a solid electrolyte by stirring the electrolyte admixture. The method may further include precipitating the solid electrolyte by evaporating the solvent admixture, and heat treating the precipitated solid electrolyte. In particular, the solvent admixture may include the second polar organic solvent in an amount of about 0.01 to 0.03 wt % based on the total weight of the first polar organic solvent.