Argyrodite Sulfide Solid Electrolyte with PS4 Distortion Control

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Solution Overview

Problem

There is a demand for further improvement in lithium ion conductivity of sulfide solid electrolytes used in all-solid-state lithium ion secondary batteries.

Innovation Solution

Introduce structural distortion into the PS4 tetrahedron of the argyrodite crystal structure by substituting P elements with Si, Al, Sn, In, Cu, Sb, or Ge, and/or substituting S elements with O or Ha elements, and control the average distance between these elements within specific ranges to enhance lithium ion conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the lithium ion conductivity is increased through compositional changes, then the charge and discharge efficiency improves, but the crystal structure stability may be compromised

Engineering Contradiction:

Improvecharge and discharge speedVSAvoidcrystal structure stability

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The invention achieves high charge and discharge speed (lithium ion conductivity ≥4.0 mS/cm) by precisely controlling the structural distortion parameter Δ within 0.05-0.30 Å, while maintaining the argyrodite crystal structure. This controlled parameter change enables fast ion transport without compromising the fundamental structural stability of the material

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite crystal structure that combines the stable argyrodite framework with controlled structural distortion. The resulting material integrates the stability of the parent structure with the enhanced ion conductivity of the distorted configuration, achieving both high productivity and compositional stability

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 resulting sulfide solid electrolyte exhibits improved lithium ion conductivity, leading to better output characteristics and low-temperature performance in lithium ion secondary batteries, particularly in all-solid-state batteries.

Implementation Method 1

Sulfide ions constituting the sulfide solid electrolytes have higher polarizability and higher ion conductivity than those of oxide ions constituting the oxide solid electrolytes

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

the crystal structure includes a plurality of PS4 tetrahedrons T1 with the P element at a center and four S elements at vertices, in a part of the PS4 tetrahedrons T1, the P element may be substituted with at least one element selected from the group consisting of a Si element, an Al element, a Sn element, an In element, a Cu element, an Sb element, and a Ge element

Methodology Applied

Scientific EffectCrystal structure distortion: Deformation

Data Source

PatentEP4607539A1Sulfide solid electrolyte and method for producing same, electrode mixture, solid electrolyte layer, and all-solid-state lithium ion secondary battery

Publication Date: 2025.08.27 AGC INC

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Figure 3A~3B

AI summary

The present invention pertains to a sulfide solid electrolyte that contains Li, P, S, and Ha, and that has an argyrodite-type crystal structure. The crystal structure has a plurality of PS4 tetrahedrons T1 in which a part of elements is optionally substituted. In the sulfide solid electrolyte, 16 elements that serve as apexes of the PS4 tetrahedrons T1 exist in a unit lattice, and the average value of the distance Δ, obtained by making said elements correspond to the S element positions at 16e sites of a PS4 tetrahedron T2 of a space group F-43m, is 0.05-0.30 Å.