Sulfide Solid Electrolyte with Boron Substitution for Ion Conductivity and Reduction Resistance
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Solution Overview
Problem
Current sulfide solid electrolyte materials, such as LiGePS-based materials, exhibit favorable ion conductivity but are low in reduction resistance, particularly during battery charging.
Innovation Solution
A sulfide solid electrolyte material with a specific crystal structure characterized by a peak at 2θ=29.58° in X-ray diffraction, where part of the P element is substituted with B, enhancing ion conductivity and reduction resistance by altering the crystal phase ratios and element positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiGePS-based sulfide solid electrolyte material is used, then ion conductivity is improved, but reduction resistance deteriorates
Solution Approach 1:
The patent applies local quality by substituting P elements at specific crystallographic sites (4a site) with Pb elements, while maintaining Ge elements at other sites (4b site). This localized substitution at specific positions within the crystal structure improves reduction resistance without compromising the overall ion conductivity of the material.
Solution Approach 2:
The patent changes the compositional parameters by controlling the ratio of Pb to P elements and optimizing the crystal phase composition (specifically the ratio of monoclinic to triclinic phases). By adjusting these parameters within specific ranges, the material achieves both high ion conductivity and improved reduction resistance simultaneously.
2Reliability
If crystal phase ratio is optimized for ion conductivity, then ion conductivity is improved, but reduction resistance deteriorates
Solution Approach 1:
The patent optimizes specific compositional parameters (Pb content, P content, and crystal phase ratios) within defined ranges. By controlling the monoclinic phase to constitute 20-80% of the total crystal phase and adjusting the Pb/(Pb+P) ratio to 0.1-0.8, the material achieves simultaneous improvement in both ion conductivity and reduction resistance.
Solution Approach 2:
The patent creates a composite crystal structure containing both monoclinic and triclinic phases in specific proportions, along with Pb-substituted P sites. This composite approach allows the material to benefit from the high ion conductivity of the monoclinic phase while the triclinic phase and Pb substitution provide enhanced reduction resistance.
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 ion conductivity and improved reduction resistance, preventing reductive decomposition and maintaining battery performance.
Implementation Method 1
A sulfide solid electrolyte material with favorable ion conductivity and high reduction resistance
Implementation Method 2
high reduction resistance, preventing reductive decomposition and maintaining battery performance
Data Source
AI summary
A sulfide solid electrolyte material with favorable ion conductivity and high reduction resistance. The object is attained by providing sulfide solid electrolyte material comprising: Li element; Ge element; P element; and S element, wherein the sulfide solid electrolyte material peaks at a position of 2θ=29.58°±0.50° in X-ray diffraction measurement using CuKα ray, the sulfide solid electrolyte material does not peak at a position of 2θ=27.33°±0.50° in X-ray diffraction measurement using CuKα ray or when diffraction intensity at the peak of 2θ=29.58°±0.50° is regarded as IA and diffraction intensity at the peak of 2θ=27.33°±0.50° is regarded as IB, a value of IB/IA is less than 1.0, and part of the P element in a crystal phase peaking at the position of 2θ=29.58°±0.50° is substituted with a B element.