Sulfide Solid Electrolyte Ion Conductivity
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Solution Overview
Problem
Current solid electrolyte materials for lithium batteries lack favorable ion conductivity, limiting battery output and requiring additional safety measures due to the use of flammable organic solvents in liquid electrolytes.
Innovation Solution
A sulfide solid electrolyte material with a specific crystal structure and composition, characterized by the absence of a peak at 2θ = 27.33° in X-ray diffraction measurements and a high ratio of crystal phases with peaks at 29.58°, incorporating oxygen substitution to enhance ion conductivity, is developed. This material includes octahedron and tetrahedron structures with specific elements like Li, Ge, P, and S, and oxygen substitution improves ion conduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolyte containing flammable organic solvent is used in lithium battery, then the battery can achieve commercialization and basic functionality, but safety devices are required to restrain temperature rise during short circuit and prevent short circuit
Solution Approach 1:
The patent extracts and eliminates the flammable organic solvent from the electrolyte system, replacing it with a solid electrolyte layer composed of inorganic compounds. This removal of the harmful component (flammable solvent) directly resolves the safety contradiction by eliminating the need for safety devices while maintaining battery functionality.
Solution Approach 2:
The patent changes the physical state parameter of the electrolyte from liquid to solid, and transitions from organic to inorganic composition. This parameter change fundamentally alters the safety characteristics, eliminating flammability while maintaining ionic conductivity, thus resolving the safety contradiction without adding complex safety devices.
2Reliability
If conventional sulfide solid electrolyte materials are used, then the solid electrolyte layer can be formed to eliminate flammable solvents, but the ion conductivity is insufficient to achieve high battery output
Solution Approach 1:
The patent creates a composite solid electrolyte material combining multiple inorganic compounds (Li2SiO3, P2S5, Li2S) in specific proportions. This composite approach synergistically improves ion conductivity beyond what individual materials can achieve, enabling high battery output while maintaining the safety benefits of solid electrolytes.
Solution Approach 2:
The patent optimizes compositional parameters by adjusting the ratios of Li2SiO3, P2S5, and Li2S, and controls processing parameters including sintering temperature (400-600°C) and time (1-24 hours). These parameter changes maximize ion conductivity to achieve the required power output for high-performance batteries.
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 sulfide solid electrolyte material achieves high ion conductivity, enabling the development of high-output batteries with improved safety by eliminating the need for flammable organic solvents and enhancing battery performance.
Implementation Method 1
a sulfide solid electrolyte material with favorable ion conductivity
Implementation Method 2
in the X-ray diffraction measurement using the CuKα ray
Implementation Method 3
a diffraction intensity at the above-mentioned peak of 2θ = 29.58° ± 0.50° is regarded as I A and a diffraction intensity at the above-mentioned peak of 2θ = 27.33° ± 0.50° is regarded as I B
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The object of the present invention is to provide a sulfide solid electrolyte material with favorable ion conductivity. The present invention attains the object by providing a sulfide solid electrolyte material comprising an M1 element (such as a Li element), an M2 element (such as a Ge element and a P element), a S element and an O element, and having a peak at a position of 2θ = 29.58° ± 0.50° in an X-ray diffraction measurement using a CuKα ray, characterized in that when a diffraction intensity at the peak of 2θ = 29.58° ± 0.50° is regarded as IA and a diffraction intensity at a peak of 2θ = 27.33° ± 0.50° is regarded as IB, a value of IB/IA is less than 0.50.