Sulfide Solid Electrolyte Moisture Stability via Sn-P Composition

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Solution Overview

Problem

Current sulfide solid electrolyte materials for lithium batteries exhibit favorable ion conductivity but are low in stability against moisture, particularly the LiGePS-based materials.

Innovation Solution

A sulfide solid electrolyte material comprising specific elements like Li, Na, K, Mg, Ca, and Zn, along with P and Sn, characterized by a high ratio of crystal phase peaks in X-ray diffraction measurements, ensuring favorable ion conductivity and enhanced stability against moisture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If LiGePS-based sulfide solid electrolyte material is used, then ion conductivity is improved, but stability against moisture deteriorates

Engineering Contradiction:

Improveion conductivityVSAvoidstability against moisture

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the compositional parameters by introducing Sn elements and adjusting the ratio of M2 elements (specifically containing P and Sn) to achieve a crystal phase with peak at 2θ=29.58°±0.50° where IB/IA<0.50. This parameter optimization simultaneously improves ion conductivity and moisture stability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite sulfide solid electrolyte material combining multiple M2 elements (P, Sn, and optionally Ge, Si, Sb) in specific ratios. This composite approach with M2 containing at least P and Sn achieves both high ion conductivity and enhanced moisture stability that single-element materials cannot provide

Inventive Principle:

Principle #40Composite materials

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 stability against moisture, improving the performance and reliability of lithium batteries.

Implementation Method 1

a Li ion conductor (a sulfide solid electrolyte material) having a composition of Li(4−x)Ge(1−x)PxS4 is disclosed

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 2

having a peak at a position of 2θ=29.58°±0.50° in X-ray diffraction measurement using a CuKα ray

Methodology Applied

Scientific EffectX-ray diffraction: X-Ray

Data Source

PatentUS10388985B2Sulfide solid electrolyte material, battery, and producing method for sulfide solid electrolyte material

Publication Date: 2019.08.20 TOYOTA JIDOSHA KK

AI summary

The main object of the present invention is to provide a sulfide solid electrolyte material having favorable ion conductivity and high stability against moisture. The present invention solves the above-mentioned problem by providing a sulfide solid electrolyte material comprising an M1 element (such as Li element), an M2 element (such as Ge element, Sn element and P element) and a S element, and having a peak at a position of 2θ=29.58°±0.50° in X-ray diffraction measurement using a CuKα ray, characterized in that when a diffraction intensity at the above-mentioned 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, and the M2 contains at least P and Sn.