Sulfide Solid Electrolyte Morphology for Moisture-Resistant Slurries
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Solution Overview
Problem
In solid-state batteries, sulfide solid electrolytes with small particle sizes and low specific surface areas are needed to reduce viscosity in slurries, minimize solvent usage, and prevent hydrogen sulfide gas generation and conductivity loss due to moisture reaction, while maintaining battery productivity and safety.
Innovation Solution
A sulfide solid electrolyte containing lithium, phosphorus, and sulfur with a controlled median diameter and specific surface area ratio, produced through thermal treatment and pulverization to achieve spherical particle shapes, reducing the area of reaction with moisture and enhancing lithium ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the particle size of the sulfide solid electrolyte is reduced by pulverization, then the uniform distribution inside electrodes is improved, but the specific surface area increases causing increased solvent adsorption and slurry viscosity
Solution Approach 1:
The patent applies parameter changes by controlling the D50 within 0.1-2.0 μm and the (A×B)/C value within 1.0-2.5, where A is BET specific surface area, B is true density, and C is CS value. These parameter specifications directly address the contradiction by defining the optimal range that achieves both fine particle size for uniform distribution and controlled specific surface area to minimize solvent adsorption and maintain slurry processability.
2Manufacturing precision
If the particle size of the sulfide solid electrolyte is reduced, then the uniform distribution inside electrodes is improved, but the reaction area with atmospheric moisture increases causing hydrogen sulfide gas generation and ionic conductivity decrease
Solution Approach 1:
The patent resolves this contradiction by simultaneously controlling two parameters: the particle size (D50: 0.1-2.0 μm) to ensure uniform distribution, and the specific surface area parameter ((A×B)/C: 1.0-2.5) to limit the reaction area with moisture. This dual parameter control achieves fine particle size benefits while minimizing the harmful effects of increased surface area.
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 approach results in reduced solvent requirements, decreased hydrogen sulfide gas generation, and improved ionic conductivity, thereby enhancing battery productivity and safety while maintaining low costs.
Implementation Method 1
subjecting the intermediate to thermal treatment and pulverizing the resulting thermally-treated product
Implementation Method 2
pulverizing the resulting thermally-treated product to obtain a pulverized product that has a median diameter D50 of 0.10 μm or more and 2.0 μm or less
Implementation Method 3
only lithium ions move and thus a side reaction due to movements of anions does not occur
Data Source
AI summary
Provided are a sulfide solid electrolyte having a small particle size and a low specific surface area; an electrode composite material, a slurry and a battery in each of which the sulfide solid electrolyte is used; and a method of producing the sulfide solid electrolyte. The sulfide solid electrolyte contains lithium (Li), phosphorus (P) and sulfur (S) elements and has: a median diameter D50 of 0.10 μm or more and 2.0 μm or less; and a value of the formula: (A×B)/C, wherein A represents a BET specific surface area (m2/g), B represents a true density (g/cm3), and C represents a CS value (m2/cm3), of 1.0 or more and 2.5 or less.