Sulfide Solid Electrolyte Composition for Higher Ionic Conductivity
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Solution Overview
Problem
Current sulfide-based inorganic solid electrolyte materials for lithium ion batteries have room for improvement in ionic conductivity.
Innovation Solution
A sulfide-based inorganic solid electrolyte material with a specific composition and structure, including Li, P, and S, where the area of peaks derived from the P2S6 glass structure is 0.1 or more in a 31P-NMR spectrum, is developed to enhance ionic conductivity by optimizing the raw material composition and manufacturing method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sulfide-based inorganic solid electrolyte materials are used, then the battery structure is simplified and safety is improved, but the ionic conductivity is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional ratios of Li, P, and S elements in the sulfide-based solid electrolyte material. By adjusting the stoichiometric ratios and processing parameters during synthesis, the patent achieves optimal ionic conductivity while maintaining manufacturing feasibility. This resolves the contradiction by finding the right parameter window that satisfies both performance and manufacturability requirements.
Solution Approach 2:
The patent employs composite material design by creating a multi-phase sulfide-based solid electrolyte system containing specific crystalline phases and glassy phases. The composite structure combines different phases with complementary properties, where the crystalline phases provide structural stability and the glassy phases contribute to high ionic conductivity. This approach enables achieving high ionic conductivity while maintaining ease of manufacture through conventional sintering processes.
2Reliability
If the P2S6 glass structure content is increased to improve ionic conductivity, then the ionic conductivity increases, but the structural stability may be compromised
Solution Approach 1:
The patent applies local quality by creating a heterogeneous microstructure where regions with high P2S6 glass content (providing high ionic conductivity) are distributed within a matrix of stable crystalline phases. This local concentration of glassy phases in specific regions allows the material to achieve high overall ionic conductivity while the surrounding crystalline structure maintains structural stability. The spatial distribution of different phases with different properties resolves the contradiction between conductivity and stability.
Solution Approach 2:
The patent uses composite material design to create a two-phase system where crystalline phases (such as Li10P3S12) provide structural stability and glassy P2S6 phases provide high ionic conductivity pathways. The composite structure allows each phase to fulfill its specific function: the crystalline framework maintains structural integrity while the glassy regions serve as fast ion conduction channels. This functional division resolves the contradiction between structural stability and ionic conductivity.
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 significant improvement in ionic conductivity, achieving values of 1.0×10−3 S/cm or higher, suitable for lithium ion batteries, by effectively filling gaps between crystal structures with a sufficient amount of P2S6 glass.
Implementation Method 1
in a spectrum obtained by 31P-NMR measurement, when a total area of peaks derived from a PS4 structure is represented by 1, a total area of peaks derived from a P2S6 glass structure is 0.1 or more
Data Source
AI summary
Provided is a sulfide-based inorganic solid electrolyte material including Li, P, and S as constituent elements, in which in a spectrum obtained by 31P-NMR measurement, when a total area of peaks derived from a PS4 structure is represented by 1, a total area of peaks derived from a P2S6 glass structure is 0.1 or more.