Sulfide Solid Electrolyte Particle Shape for High-Density Battery Packing
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Solution Overview
Problem
Sulfide-based solid electrolytes have irregular shapes and wide particle size distributions, leading to difficulties in high-density packing with electrode active materials, which reduces ion conductivity and energy density in all-solid-state batteries.
Innovation Solution
The sulfide-based solid electrolyte is designed with specific morphological parameters, including a parameter value of 0.8 or greater in SEM images, aspect ratio of 0.7 to 1.5, and average particle diameter of 70 µm or less, ensuring high-density packing and maintaining ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sulfide-based solid electrolyte particles are prepared by conventional methods (solid-phase milling or liquid-phase precipitation), then the electrolyte can be produced, but the particles have irregular shapes and wide particle size distributions, making it difficult to achieve high-density packing with electrode active materials
Solution Approach 1:
The patent changes the preparation method from conventional solid-phase or liquid-phase methods to a gas-phase reaction method, where metal organic compounds and sulfur vapor react to form sulfide-based solid electrolyte particles. This parameter change enables precise control over particle morphology and size distribution, producing spherical particles with narrow size distribution that can be densely packed with electrode active materials
Solution Approach 2:
The patent utilizes phase transitions by vaporizing metal organic compounds and sulfur to form a gas-phase reaction environment. The vaporized precursors condense and react to form solid electrolyte particles with controlled morphology. This phase transition approach enables precise particle size and shape control that conventional methods cannot achieve
2Ease of manufacture
If sulfide-based solid electrolyte particles have large particle diameters, then manufacturing is easier, but many micropores are induced, causing ion conductivity to decrease
Solution Approach 1:
The gas-phase reaction method allows independent control of particle size and morphology parameters. By adjusting reaction conditions such as temperature, vapor flow rates, and precursor ratios, the patent produces particles with optimal sizes that minimize micropore formation while maintaining ease of manufacture and high ion conductivity
3Quantity of substance
If the solid electrolyte and electrode active material are mixed to maximize energy density, then battery capacity increases, but irregular-shaped electrolyte particles make high-density packing difficult
Solution Approach 1:
The patent produces sulfide-based solid electrolyte particles with uniform spherical shapes and narrow size distributions through gas-phase reaction. This morphological uniformity enables efficient mixing and high-density packing with electrode active materials, maximizing the proportion of active material in the electrode while maintaining good contact and high energy density
Data Source
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AI summary
The present invention relates to a sulfide-based solid electrolyte and an all-solid-state battery including the same. According to one aspect of the present invention, the sulfide-based solid electrolyte includes at least one sulfide-based solid particle, and, in a scanning electron microscope (SEM) image of the at least one sulfide-based solid particle, a parameter value (C) defined by the following [Mathematical Formula 1] is 0.8 or greater. C=4πA/P2 wherein A is the area of a region defined along the outline of the at least one sulfide-based solid particle in the SEM image, and P means the length of the perimeter of the region.