Sulfide Solid Electrolyte Surface Passivation for H2S Suppression

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Solution Overview

Problem

Conventional sulfide solid electrolyte materials for lithium batteries face challenges in maintaining water resistance in high-moisture environments, leading to the generation of H2S and compromising ion conductivity.

Innovation Solution

Incorporating a transition element from group 3 to 12, such as Ta, Nb, or W, which forms a stable sulfide on the surface, suppressing H2S generation and enhancing water resistance while promoting high ion conductivity by optimizing the crystal structure and composition, including elements like Li, Ge, P, and S, to achieve a peak at 2θ=29.58° in X-ray diffraction and minimizing the peak at 2θ=27.33° with a diffracted intensity ratio of IB/IA < 1.00.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional sulfide solid electrolyte materials are used, then ion conductivity can be achieved, but water resistance deteriorates in high-moisture environments leading to H2S generation

Engineering Contradiction:

Improvewater resistanceVSAvoidH2S generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

A coating layer comprising a transition metal sulfide is formed on the surface of the sulfide solid electrolyte material. This coating layer acts as an intermediary barrier between the electrolyte material and the high-moisture environment, preventing direct contact and reaction that would otherwise generate H2S. The coating layer specifically suppresses H2S generation while maintaining ion conductivity through the electrolyte.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 material exhibits excellent water resistance and high ion conductivity even in high-moisture conditions, enabling the development of high-output batteries with improved safety and performance.

Implementation Method 1

Incorporating a transition element from group 3 to 12, such as Ta, Nb, or W, which forms a stable sulfide on the surface, suppressing H2S generation and enhancing water resistance

Methodology Applied

Scientific EffectSurface passivation:

Implementation Method 2

the sulfide solid electrolyte material has a peak at a position of 2θ=29.58°±0.50°, in X-ray diffraction measurement using a CuKα beam

Methodology Applied

Scientific EffectX-ray diffraction: X-Ray

Implementation Method 3

in X-ray diffraction measurement using a CuKα beam

Methodology Applied

Scientific EffectBragg diffraction: Bragg Diffraction

Data Source

PatentUS20240178445A1Sulfide solid electrolyte material, battery, and method of manufacturing sulfide solid electrolyte material

Publication Date: 2024.05.30 TOYOTA JIDOSHA KK

AI summary

A sulfide solid electrolyte material contains element M1, element M2, element M3 and element S. Element M1 is at least one type selected from the group consisting of Li, Na, K, Mg Ca and Zn, and contains at least one of Li and Na. Element M2 is at least one type selected from the group consisting of P, Sb, Si, Ge, Sn, B, Al, Ga, In, Ti, Zr and V, and contains at least P.