Sulfide Solid Electrolyte Halide Coating for Lower Slurry Viscosity
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Solution Overview
Problem
The synthesis of sulfide-based solid electrolyte materials often results in particles that are too small, leading to increased viscosity in slurry used for solid-state electrochemical cell processing, making it difficult to achieve optimal contact between the electrolytes and active materials.
Innovation Solution
The development of a process where sulfide-based solid electrolyte materials are mixed and heated with an alkali metal halide, which melts and forms a flux, coating the primary particles and forming a matrix without being incorporated into the crystal structure, thereby controlling particle size and maintaining ionic conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional ball milling techniques are used to synthesize solid electrolyte material, then the synthesis process is simple and easy to implement, but the average particle size of the resulting solid electrolyte is much larger than that of the active materials
Solution Approach 1:
The patent changes the synthesis parameters by using a sol-gel process instead of traditional ball milling, controlling the particle size through solution chemistry parameters such as precursor concentration, drying temperature, and calcination conditions to achieve the desired sub-micron particle size range
Solution Approach 2:
The patent replaces the mechanical ball milling system with a chemical sol-gel synthesis system, where particles are formed through chemical reactions in solution and then dried and calcined, avoiding the mechanical forces that produce large particles in ball milling
2Volume of moving object
If the synthesized electrolyte is further milled or ground to reduce the average particle size to a desired amount, then the particle size is reduced, but a large amount of fine particles are created which increase the viscosity of the slurry
Solution Approach 1:
The patent performs preliminary particle size control during the synthesis process itself by using sol-gel methodology that naturally produces uniformly small particles, rather than attempting to reduce particle size after synthesis through additional milling that would create excessive fine particles
Solution Approach 2:
The patent changes the physical state and distribution of particles by controlling the sol-gel process parameters to produce a controlled amount of fine particles that remain suspended in the slurry rather than settling, maintaining manageable slurry viscosity
3Manufacturing precision
If the average particle size of the solid electrolyte is made smaller to ensure optimal contact with active materials, then the contact between electrolytes and active materials is improved, but the viscosity of the slurry increases making later processing difficult
Solution Approach 1:
The patent optimizes the slurry formulation parameters including solvent composition, binder content, and particle size distribution to achieve a balance where small particles provide good contact while the slurry maintains processable viscosity through appropriate rheological control
Solution Approach 2:
The patent uses a composite slurry system combining solid electrolyte particles with specific binders and solvents that provide both good particle dispersion for optimal contact and appropriate flow properties for easy processing
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 approach effectively grows the particle size of sulfide-based solid electrolytes, reducing the viscosity of the slurry and improving processing ease, while maintaining desirable ionic conductivity and achieving optimal contact between electrolytes and active materials in solid-state batteries.
Implementation Method 1
heating the combined solid electrolyte with an alkali metal halide to melt the alkali metal halide
Implementation Method 2
cooling the combined solid electrolyte and alkali metal halide
Data Source
AI summary
A sulfide-based solid electrolyte composition contains lithium, sulfur, and phosphorus, and is partially coated with an amorphous layer that includes an alkali metal halide. Alternatively, the sulfide-based solid electrolyte composition is dispersed in a matrix of an alkali metal halide. The sulfide-based solid electrolyte composition is suitable for use in solid-state batteries.