Lithium Sulfide Powder Process for Fine Particle Solid Electrolytes
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Solution Overview
Problem
Commercially available lithium sulfide (Li2S) powders have low cycling stability, high initial activation potential, and large particle sizes, which hinder their effectiveness as battery components, and existing methods require complex raw materials, high temperatures, and catalysts.
Innovation Solution
A process to produce Li2S powder with a d50-value of less than 10 μm, specific surface area of more than 5 m2/g, and a high percentage of pores below 20 nm, achieved by grinding and heating lithium hydroxide monohydrate to reduce particle size and water content, then reacting it with a sulfide reactant without a catalyst or solvent, at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods are used to produce Li2S powder, then the production process is simpler, but the particle size is large (over 100 μm) and requires further processing
Solution Approach 1:
The patent performs preliminary grinding of lithium hydroxide monohydrate to obtain fine particles (d50 < 10 μm) before the reaction with sulfur source. This preliminary size reduction action ensures that the final Li2S powder has the desired fine particle size without requiring additional processing steps after production.
2Speed
If high temperature processing is used, then the reaction kinetics are improved, but the energy consumption and process complexity increase
Solution Approach 1:
The patent changes the particle size parameter of the reactants (using ground LiOH monohydrate with d50 < 10 μm) to increase the reaction surface area. This parameter change allows the reaction to proceed efficiently at lower temperatures (100-260°C), reducing energy consumption while maintaining good reaction kinetics.
3Ease of manufacture
If Li2S powder with large particle size is used, then the manufacturing cost is lower, but the cycling stability and activation potential are poor
Solution Approach 1:
The patent performs preliminary grinding of lithium hydroxide monohydrate to obtain fine particles (d50 < 10 μm) before the reaction with sulfur source. This preliminary size reduction action ensures that the final Li2S powder has the desired fine particle size without requiring additional processing steps after production.
4Productivity
If complex raw materials and catalysts are used, then the reaction efficiency is improved, but the process complexity and cost increase
Solution Approach 1:
The patent extracts and eliminates the need for catalysts and complex raw materials from the conventional process. By using ground lithium hydroxide monohydrate as the reactant, the process achieves efficient Li2S production without requiring any catalysts, thereby simplifying the overall process while maintaining high reaction efficiency.
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 resulting Li2S powder exhibits improved agglomeration and dispersion properties, reducing the need for additional processing and making it suitable for high-quality solid electrolytes without increasing process complexity or cost.
Implementation Method 1
heating such LiOH powder C at a temperature of less than 180° C., in order to obtain the LiOH powder A
Implementation Method 2
reacting such LiOH powder A with a sulfide reactant, in order to obtain the Li2S powder
Data Source
AI summary
The present disclosure relates to a process of obtaining a powder of lithium sulfide (Li2S powder) having a d50-value of less than 10 μm, a specific surface area of more than 5 m2/g, a total pore volume of more than 0.035 cm3/g and a percentage of total pore volume constituted of pore with diameter below 20 nm of more than 20%, comprising the steps of: a) providing a powder of lithium hydroxide having a d50-value of less than 10 μm and presenting a residual water content below 5 wt. % (LiOH powder A), and b) reacting such LiOH powder A with a sulfide reactant, in order to obtain the Li2S powder. The present disclosure also relates to the powder of lithium sulfide obtained from such process and the use of such Li2S powder to prepare a solid compound of formula (I): LiaPSbXc wherein —X represents at least one halogen element; —a represents a number from 3.0 to 6.0; —b represents a number from 3.5 to 5.0; and —c represents a number from 0 to 3.0.