Sulfide Solid Electrolyte Hydrogen Sulfide Reduction
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Solution Overview
Problem
Sulfide solid electrolyte materials generate hydrogen sulfide when exposed to water, limiting their stability and requiring further reduction in hydrogen sulfide production to enhance safety and performance in lithium batteries.
Innovation Solution
A method involving a two-stage vitrification process to produce a sulfide solid electrolyte material by first forming an intermediate with crosslinking sulfur and then removing it using a bond cleaving compound, such as Li2O, to eliminate Li2S and crosslinking sulfur, resulting in a material that generates a very small amount of hydrogen sulfide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If sulfide solid electrolyte material is used to achieve high Li ion conductivity, then battery output is improved, but hydrogen sulfide generation occurs when contacting water reducing stability
Solution Approach 1:
The patent changes the compositional parameters of the sulfide solid electrolyte by precisely controlling the molar ratios of Li2S, P2S5, and Li2O to achieve the specific composition range (40-70 mol% Li2S, 10-30 mol% P2S5, 10-30 mol% Li2O). This parameter optimization reduces hydrogen sulfide generation while preserving lithium ion conductivity, thereby resolving the contradiction between power output and material stability.
Solution Approach 2:
The patent creates a composite sulfide solid electrolyte material by combining multiple components (Li2S, P2S5, and Li2O) in specific proportions. This composite approach allows the material to benefit from the high lithium ion conductivity of sulfides while the specific composition reduces hydrogen sulfide generation, thus resolving the contradiction between power and stability.
2Reliability
If Li2S proportion is increased to achieve ortho composition and reduce hydrogen sulfide generation, then stability is improved, but Li ion conductivity drops
Solution Approach 1:
The patent optimizes the Li2S content parameter within the specific range of 40-70 mol%, avoiding both excessive Li2S (which causes high hydrogen sulfide generation) and insufficient Li2S (which reduces lithium ion conductivity). This precise parameter control resolves the contradiction between stability improvement and conductivity maintenance.
Solution Approach 2:
The patent introduces Li2O as a local modification component that specifically addresses the hydrogen sulfide generation issue without compromising the overall lithium ion conductivity. The Li2O acts locally to stabilize the structure and reduce harmful reactions, allowing the material to maintain high conductivity while improving stability.
3Ease of manufacture
If single vitrification process is used to simplify production, then manufacturing complexity is reduced, but hydrogen sulfide generation cannot be sufficiently controlled
Solution Approach 1:
The patent segments the vitrification process into two distinct stages: first vitrification to form the base glassy matrix, and second vitrification to achieve final composition optimization. This segmentation allows precise control over the formation of Li2S-P2S5-Li2O phases, enabling sufficient control of hydrogen sulfide generation while maintaining reasonable manufacturing 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 results in a highly safe sulfide solid electrolyte material with improved stability and reduced hydrogen sulfide generation, enhancing the safety and performance of lithium batteries.
Implementation Method 1
forming an intermediate having crosslinking sulfur but no Li2S, by vitrifying, in a first vitrification process, a starting material composition
Implementation Method 2
eliminating the crosslinking sulfur by vitrifying, in a second vitrification process, an intermediate-containing composition
Data Source
AI summary
A method of producing a sulfide solid electrolyte material includes: forming an intermediate having crosslinking sulfur but no Li2S, by vitrifying, in a first vitrification process, a starting material composition obtained by mixing Li2S and a sulfide of a group 14 or group 15 element such that a proportion of Li2S with respect to the sum total of the Li2S and the sulfide of a group 14 or group 15 element is smaller than a proportion of Li2S required for the sulfide solid electrolyte material to obtain an ortho composition; and eliminating the crosslinking sulfur by vitrifying, in a second vitrification process, an intermediate-containing composition resulting from mixing a bond cleaving compound, which cleaves a bond of the crosslinking sulfur, with the intermediate.