Solid Electrolyte Preparation Using Elemental Powders
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Solution Overview
Problem
The high cost and safety concerns associated with using compound-based starting materials for sulfide-based solid electrolytes in lithium secondary batteries, which hinder the development of large-area battery technology due to material costs and handling risks.
Innovation Solution
A method of preparing a solid electrolyte using simple substance powders of sulfur, phosphorus, and lithium, optionally with nickel or chlorine, through a process involving mixing, milling to form an amorphous powder, and heat-treating to crystallize, eliminating the need for compound-type starting materials and reducing material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compound type starting materials (Li2S, P2S5) are used to manufacture sulfide-based solid electrolyte, then the electrolyte performance is improved, but the material cost increases significantly
Solution Approach 1:
The compound starting materials (Li2S, P2S5) are segmented into their constituent simple element powders (Li, S, P). These simple elements are mixed in specific ratios and then subjected to mechanical alloying and heat treatment to form the desired sulfide-based solid electrolyte compound structure, thereby avoiding the high cost of pre-synthesized compounds while achieving the same performance.
Solution Approach 2:
The invention changes the chemical composition parameters by using simple elements instead of compounds. By controlling the mixing ratios of Li, S, and P powders and applying specific heat treatment parameters (temperature, time, atmosphere), the desired electrolyte phase is formed, achieving cost reduction without sacrificing performance.
2Reliability
If compound type starting materials are used, then the electrolyte performance is improved, but the handling safety deteriorates due to specialized equipment requirements
Solution Approach 1:
The hazardous compound materials are segmented into simple, stable elemental powders (metallic Li, S8, P4) that can be handled more safely. These simple elements do not require specialized handling equipment and can be processed in conventional laboratory or industrial environments, eliminating safety risks while maintaining electrolyte performance through controlled synthesis.
Solution Approach 2:
The invention converts the potential harm of handling unstable compounds into a benefit by using stable simple elements as starting materials. The simple elements are inherently safer to handle but can be transformed through controlled mechanical alloying and heat treatment into the desired high-performance electrolyte compound, thus converting a safety disadvantage into a safety advantage.
3Ease of manufacture
If simple substance powders are used instead of compound powders, then the material cost is reduced, but the manufacturing process complexity increases
Solution Approach 1:
The invention applies preliminary mechanical alloying treatment to the mixed simple element powders before heat treatment. This preliminary action of mechanical mixing and ball milling ensures uniform distribution of Li, S, and P particles and pre-forms the amorphous or nanocrystalline structure, which facilitates subsequent crystallization during heat treatment and simplifies the overall process by eliminating the need for multiple intermediate steps.
Solution Approach 2:
The manufacturing process utilizes phase transitions as a simplifying mechanism. The mixed simple element powders are first mechanically alloyed to form an amorphous phase, then subjected to heat treatment that induces crystallization into the desired electrolyte phase. This phase transition approach simplifies the process by combining multiple transformations (mixing, amorphization, crystallization) into a controlled thermal sequence, reducing overall process complexity.
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 enables the production of solid electrolytes with lithium-ionic conductivity and discharge capacity comparable to or exceeding existing technologies at significantly lower costs, while ensuring safety without the need for specialized handling equipment, facilitating the development of large-area all-solid-state batteries.
Implementation Method 1
milling the mixed powder to obtain an amorphous powder
Implementation Method 2
heat-treating the amorphous powder to crystallize
Data Source
AI summary
A method of preparing a solid electrolyte includes preparing a mixed powder with a sulfur powder, a phosphorus powder and a lithium powder. The sulfur in the sulfur powder, the phosphorus in the phosphorus powder, and the lithium in the lithium powder are each in an elemental form. The mixed powder is milled to obtain an amorphous powder. The method includes heat-treating the amorphous powder to form a crystallized solid electrolyte.