Sulfide Solid Electrolyte Phase Ratio Control
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Solution Overview
Problem
Sulfide solid electrolytes often produce hazardous hydrogen sulfide, which complicates the safety and efficiency of all-solid-state batteries, and they typically have low ionic conductivity at room temperature.
Innovation Solution
A sulfide solid electrolyte material containing phosphorus and sulfur, with a specific crystalline-vitreous PS4 ratio of 0.00926≤x≤0.37, where x represents the ratio of integrated intensities from 31P-NMR spectra, is developed to enhance ionic conductivity while minimizing hydrogen sulfide production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfide solid electrolyte is used to replace liquid electrolyte, then safety is improved (nonflammable), but harmful factors worsen (hydrogen sulfide production)
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystalline-vitreous phase ratio (x) of PS4 in the sulfide solid electrolyte material. By adjusting this structural parameter within a specific range, the material simultaneously achieves high ionic conductivity and reduced hydrogen sulfide production, resolving the contradiction between safety improvement and harmful gas generation.
Solution Approach 2:
The patent employs composite material design by creating a sulfide solid electrolyte with a specific composite structure containing both crystalline and vitreous phases of PS4. This composite structure, characterized by the controlled ratio x of crystalline to total PS4, enables the material to exhibit both high ionic conductivity and low hydrogen sulfide production, thus resolving the technical contradiction.
2Reliability
If crystallinity of sulfide solid electrolyte is increased, then ionic conductivity is improved, but hydrogen sulfide production increases
Solution Approach 1:
The patent resolves this contradiction by identifying and controlling a critical parameter - the crystalline-vitreous phase ratio x of PS4. By optimizing this parameter within a specific range, the material achieves the best balance between ionic conductivity (improved by crystallinity) and hydrogen sulfide production (reduced by appropriate phase composition).
Solution Approach 2:
The patent applies local quality by creating regions with different phases (crystalline and vitreous PS4) in specific proportions. The crystalline regions provide high ionic conductivity pathways, while the controlled presence of vitreous regions suppresses hydrogen sulfide production, thus resolving the contradiction through spatial and compositional differentiation.
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 material achieves high ionic conductivity and low hydrogen sulfide production, enabling improved performance and safety in lithium-ion batteries, particularly when used in lithium-ion batteries with low-potential negative electrodes like graphite or metallic lithium.
Implementation Method 1
a first peak is a peak in a range of not less than 87.5 ppm and not more than 88.5 ppm, the peak being determined by Gaussian curve fitting of a 31P-NMR spectrum
Data Source
AI summary
A sulfide solid electrolyte material comprises phosphorus and sulfur. With regard to the sulfide solid electrolyte material, x satisfies 0.00926≤x≤0.37, where a first peak is a peak in a range of not less than 87.5 ppm and not more than 88.5 ppm, the peak being determined by Gaussian curve fitting of a 31P-NMR spectrum, a second peak is a peak in a range of not less than 84.2 ppm and not more than 85.2 ppm, the peak being determined by Gaussian curve fitting of the 31P-NMR spectrum, and a ratio of integrated intensity of the first peak to integrated intensity of the second peak is represented by x:1−x.