Sulfide Solid Electrolyte Composition for Moisture-Resistant Ion Conduction

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Solution Overview

Problem

Sulfide solid electrolytes containing the High Ion Conduction Phase (HICP) are prone to hydration, leading to decreased ionic conductivity when exposed to moisture in the air, even in a dry atmosphere, which affects their performance in energy storage applications.

Innovation Solution

A sulfide solid electrolyte with diffraction peaks in the range of 19.9°±0.5° and 23.6°±0.5° in an X-ray diffraction diagram using a CuKα ray, incorporating divalent elements and halogen elements with a combination of hydration energy greater than LiI, enhancing water resistance and maintaining high ionic conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sulfide solid electrolyte containing HICP is used, then high ionic conductivity is achieved, but the electrolyte is easily hydrated and ionic conductivity decreases when exposed to moisture

Engineering Contradiction:

Improveionic conductivityVSAvoidhydration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the chemical composition parameters of the sulfide solid electrolyte by introducing specific divalent elements (Mg, Ca, Sr, Ba, Mn, Cu, Zn) in controlled amounts (0.1-10 wt%). This compositional modification alters the hydration energy characteristics of the material, making it more resistant to water while preserving the HICP crystal structure and its high ionic conductivity properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite sulfide solid electrolyte system by combining traditional Li-I-S-P elements with divalent elements and halogen elements. This composite approach integrates the high ionic conductivity of HICP with the water resistance of divalent element halides, achieving both performance requirements simultaneously

Inventive Principle:

Principle #40Composite materials

2Reliability

If LiI is used in the sulfide solid electrolyte, then high ionic conductivity is achieved, but the material has low water resistance

Engineering Contradiction:

Improveionic conductivityVSAvoidwater resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention merges LiI (providing high ionic conductivity) with divalent element halides (providing water resistance) into a single composite sulfide solid electrolyte system. The divalent elements (Mg, Ca, Sr, Ba, Mn, Cu, Zn) are incorporated at 0.1-10 wt% to create a synergistic material that exhibits both high ionic conductivity and improved water resistance

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention modifies the hydration energy parameter of the electrolyte system by introducing divalent elements with higher hydration energies than LiI. This parameter change makes the overall system less susceptible to hydration while maintaining the beneficial ionic conductivity characteristics of LiI-containing HICP

Inventive Principle:

Principle #35Parameter changes

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 modified sulfide solid electrolyte exhibits favorable water resistance and sustained high ionic conductivity, effectively preventing hydration-induced performance degradation, even when exposed to air, thus enhancing the reliability of energy storage elements.

Implementation Method 1

a sulfide solid electrolyte which is characterized by including Li, A (A is at least one kind of P, Si, Ge, Al, and B), X (X is a halogen), and S, being a glass ceramic, and having peaks at 2θ=20.2° and 23.6° in X-ray diffraction measurement using a CuKα ray

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

having peaks at 2θ=20.2° and 23.6° in X-ray diffraction measurement using a CuKα ray

Methodology Applied

Scientific EffectX-ray diffraction: X-Ray

Implementation Method 3

X-ray diffraction diagram using a CuKα ray

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 4

a combination in which hydration energy of a compound A0.5X composed of the divalent element A and the halogen element X is greater than hydration energy of LiI

Methodology Applied

Scientific EffectHydration: Hydrates

Data Source

PatentUS20230387456A1Sulfide solid electrolyte, method for selecting elements for sulfide solid electrolyte, method for producing sulfide solid electrolyte, energy storage element, electronic device, and automobile

Publication Date: 2023.11.30 GS YUASA INT LTD

AI summary

One aspect of the present invention is a sulfide solid electrolyte, having diffraction peaks in a range of 19.9°±0.5° and a range of 23.6°±0.5° in an X-ray diffraction diagram using a CuKα ray and including one or two or more kinds of divalent elements A and one or two or more kinds of halogen elements X, in which the divalent element A and the halogen element X are a combination in which hydration energy of a compound A0.5X composed of the divalent element A and the halogen element X is greater than hydration energy of LiI.