Halide Solid Electrolyte for All-Solid-State Battery Safety
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Solution Overview
Problem
Existing solid electrolyte materials for all-solid-state batteries face challenges in achieving high ionic conductivity and safety, particularly due to sulfur content that can lead to hydrogen sulfide generation when exposed to air, affecting their covalent characteristics and ion binding properties.
Innovation Solution
A solid electrolyte material composed of Li, M, and X, where M is a metalloid or metallic element other than Li, and X is F, Cl, or Br, with specific ionic radii and electronegativity ratios, ensuring high ion binding properties and preventing decreases in ionic conductivity, and fabricated using methods like sintering of halide powders to achieve high crystallinity and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sulfur-containing solid electrolyte materials are used to achieve high ionic conductivity, then ionic conductivity is improved, but safety deteriorates due to hydrogen sulfide generation when exposed to air
Solution Approach 1:
The patent removes sulfur from the solid electrolyte composition entirely, extracting the harmful element that causes hydrogen sulfide generation. The invention uses halide-based solid electrolytes (Li3InBr6, Li3InCl6, Li3GaBr6, Li3GaCl6) that achieve high ionic conductivity without sulfur, thereby eliminating the safety hazard while maintaining performance.
Solution Approach 2:
The patent changes the chemical composition parameters by substituting sulfur-based compounds with halide-based compounds. Specifically, it uses materials with formulas Li3InBr6-xClx and Li3GaBr6-yCly where the halide ratio is controlled to optimize ionic conductivity while maintaining safety by avoiding sulfur-containing compounds that generate hydrogen sulfide.
2Stability of the object's composition
If covalent characteristics are increased in solid electrolyte materials, then structural stability is improved, but ion binding properties deteriorate leading to decreased ionic conductivity
Solution Approach 1:
The patent optimizes the halide composition ratio (x and y parameters in Li3InBr6-xClx and Li3GaBr6-yCly) to achieve the right balance between ionic conductivity and structural stability. By controlling the Br/Cl ratio, the invention maintains appropriate covalent characteristics for structural integrity while preserving ion binding properties necessary for high 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 material exhibits enhanced ionic conductivity and improved charge-discharge properties, maintaining safety by avoiding sulfur and minimizing covalent interactions, leading to better battery performance and stability.
Implementation Method 1
the solid electrolyte material having high ionic conductivity
Implementation Method 2
an X-ray diffraction pattern provided by an X-ray diffraction measurement of the solid electrolyte material; the X-ray diffraction measurement using a Cu-Kα ray
Data Source
AI summary
A solid electrolyte material is composed of Li, M, and X, where M is at least one kind of element selected from the group consisting of metalloid elements and metallic elements other than Li, and X is at least one kind of element selected from the group consisting of F, Cl, Br and I. In the solid electrolyte material, the mathematical formula FWHM/2θp≤0.015 is satisfied, where FWHM represents a half bandwidth of an X-ray diffraction peak having the highest intensity within a range of a diffraction angle 2θ of not less than 25 degrees and not more than 35 degrees in an X-ray diffraction pattern provided by an X-ray diffraction measurement of the solid electrolyte material; the X-ray diffraction measurement using a Cu-Kα ray; and 2θp represents a diffraction angle of a center of the X-ray diffraction peak.