Sulfide Solid Electrolyte Dual Structure for Reduction Resistance
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Solution Overview
Problem
The LiGePS-based sulfide solid electrolyte material has low reduction-resistance, which is a concern for battery safety and performance.
Innovation Solution
A sulfide solid electrolyte material is developed with a dual structural composition, where a first ion conductor with high ion conductivity is covered by a second ion conductor with a lower Me element to P element weight ratio, inhibiting reduction and enhancing reduction-resistance.
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 electrolyte material is segmented into two distinct structural parts: a first structural part with high ion conductivity and a second structural part with low Me element content that provides reduction resistance. This segmentation allows each part to perform its specialized function, resolving the contradiction between ion conductivity and reduction-resistance.
Solution Approach 2:
Different regions of the electrolyte material are assigned different compositions and properties. The first structural part contains higher Me element content for ion conductivity, while the second structural part contains lower Me element content for reduction resistance. This local differentiation enables simultaneous achievement of both properties in different locations.
Solution Approach 3:
The invention creates a composite electrolyte material combining two ion conductors with different compositions. The composite structure integrates the high ion conductivity of the first structural part with the reduction resistance of the second structural part, achieving properties that neither component alone could provide.
2Reliability
If Me element content is increased to improve ion conductivity, then ion conductivity is improved, but reduction-resistance deteriorates
Solution Approach 1:
The electrolyte is divided into two parts with different Me element contents. The first structural part has higher Me content optimized for ion conductivity, while the second structural part has lower Me content optimized for reduction resistance. This segmentation resolves the trade-off by distributing different functional requirements to different regions.
Solution Approach 2:
The Me element content is locally optimized in each structural part. The first structural part maintains higher Me content where ion conductivity is prioritized, while the second structural part uses lower Me content where reduction resistance is prioritized. This local quality variation enables simultaneous optimization of both properties.
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 dual structural composition improves reduction-resistance and maintains high ion conductivity, making the sulfide solid electrolyte material suitable for use in batteries.
Implementation Method 1
a first structural part composed of a first ion conductor containing a Li element, an Me element, a P element and an S element
Implementation Method 2
a second structural part composed of a second ion conductor containing a Li element, an Me element, a P element and an S element
Implementation Method 3
the first ion conductor has a peak at a position of 2θ=29.58°±0.50° in X-ray diffraction measurement using a CuKα ray
Data Source
AI summary
A sulfide solid electrolyte material with favorable reduction-resistance has a second structural part formed to cover a plurality of first structural parts, a first ion conductor composing the first structural part has a specific crystal phase with favorable ion conductivity, and a weight ratio γ of an Me element to a P element in the second structural part is less than 0.72.