Needle-like Sulfide Solid Electrolyte Synthesis via Solvent Evaporation
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Solution Overview
Problem
Existing methods for synthesizing sulfide-based solid electrolytes result in amorphous particles with a small specific surface area, reducing the contact area with electrode active materials and thus the charge and discharge capacity of all-solid batteries.
Innovation Solution
A method involving the preparation of a needle-like sulfide-based solid electrolyte by mixing Li2S, P2S5, and LiCl in an organic solvent, followed by stirring, vacuum-drying, and heat-treating to enhance the specific surface area and improve charge and discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a sulfide-based solid electrolyte is synthesized by reacting Li2S-P2S5 in a polar organic solvent, then the synthesis process is simple and suitable for mass production, but the resulting particles are amorphous and spherical with small specific surface area, reducing contact area with electrode active materials
Solution Approach 1:
The patent applies parameter changes by controlling the evaporation rate of the organic solvent through temperature management during the synthesis process. By maintaining a specific temperature range (0°C to 30°C) during solvent evaporation, the method transforms the typically spherical amorphous particles into needle-like structures with larger specific surface area, thus resolving the contradiction between simple synthesis and high surface area
Solution Approach 2:
The patent utilizes phase transitions of the organic solvent during the synthesis process. The controlled evaporation (liquid to gas phase transition) of the organic solvent from the reaction mixture enables the formation of needle-like crystal structures from the initially amorphous precipitate, thereby increasing the specific surface area while maintaining the simplicity of the synthesis method
2Ease of manufacture
If amorphous solid electrolyte particles are used, then the synthesis is straightforward, but the small specific surface area reduces the contact area between solid electrolyte and electrode active material in composite electrodes
Solution Approach 1:
The patent changes the morphological parameters of the particles by controlling the evaporation conditions of the organic solvent. By adjusting temperature and evaporation rate parameters, the method transforms spherical amorphous particles into needle-like structures with increased specific surface area, thereby increasing the contact area with electrode active materials while keeping the synthesis straightforward
3Ease of manufacture
If conventional synthesis methods are used, then the production process is simple, but the charge and discharge capacity of all-solid batteries is reduced due to small specific surface area
Solution Approach 1:
The patent applies parameter changes by controlling the evaporation temperature and rate of the organic solvent during synthesis. This transforms the particle morphology from spherical to needle-like, increasing the specific surface area which directly enhances the charge and discharge capacity of all-solid batteries while maintaining the simplicity of the production process
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 effectively increases the charge and discharge capacity of all-solid batteries while reducing capacity degradation over cycles, achieving a specific surface area of 0.2 to 1.0 m2/g and maintaining performance even with increased cycle numbers.
Implementation Method 1
the organic solvent may react with the Li2S, the P2S5, and the LiCl
Implementation Method 2
vacuum-drying the second stirred solid electrolyte
Implementation Method 3
heat-treating the vacuum-dried solid electrolyte at 350 to 550° C. for 1 to 5 hours
Data Source
AI summary
Provided is a method for preparing a needle-like sulfide-based solid electrolyte. The method may include: preparing a solid electrolyte admixture comprising an organic solvent, Li2S, P2S5, and LiCl; synthesizing a solid electrolyte by stirring the solid electrolyte admixture at a temperature of about 30 to 60° C. for about 22 to 26 hours; first stirring the solid electrolyte at a speed of about 80 to 120 rpm for about 5 to 10 minutes; after the first stirring, second stirring the first stirred solid electrolyte at a speed of about 250 to 300 rpm; vacuum-drying the second stirred solid electrolyte for about 12 to 24 hours; and heat-treating the vacuum-dried solid electrolyte at a temperature of about 350 to 550° C. for about 1 to 5 hours.