Fluorine-Gradient Sulfide Solid Electrolyte for Moisture Stability

Solution Overview

Problem

Sulfide-based solid electrolytes in all-solid-state batteries are highly reactive to moisture, leading to the generation of harmful hydrogen sulfide gas, which adversely affects safety and reduces ionic conductivity.

Innovation Solution

A solid electrolyte with a core portion and a surface portion containing fluorine-doped sulfide-based particles, featuring a concentration gradient of fluorine atoms from the surface to the core, is prepared by heat-treating sulfide-based particles with ammonium fluoride in a nitrogen atmosphere.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a polymer coating layer is formed on the sulfide-based solid electrolyte to improve moisture stability, then moisture stability is improved, but resistance increases

Engineering Contradiction:

Improvemoisture stabilityVSAvoidresistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a concentration gradient of fluorine atoms within the solid electrolyte particles, where the surface region has higher fluorine concentration for moisture stability while the core maintains lower fluorine concentration for low resistance and high ionic conductivity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the chemical composition parameter by doping fluorine atoms into the sulfide-based solid electrolyte lattice, specifically controlling the fluorine concentration to create a gradient structure that optimizes both moisture stability and electrical resistance

Inventive Principle:

Principle #35Parameter changes

2Reliability

If aluminum and nitrogen are doped in the conventional electrolyte to improve moisture stability, then moisture stability is improved, but resistance increases

Engineering Contradiction:

Improvemoisture stabilityVSAvoidresistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating a concentration gradient of fluorine atoms within the solid electrolyte particles, where the surface region has higher fluorine concentration for moisture stability while the core maintains lower fluorine concentration for low resistance and high ionic conductivity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the chemical composition parameter by doping fluorine atoms into the sulfide-based solid electrolyte lattice, specifically controlling the fluorine concentration to create a gradient structure that optimizes both moisture stability and electrical resistance

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If the sulfide-based solid electrolyte is used to achieve high ionic conductivity, then ionic conductivity is improved, but moisture stability deteriorates due to hydrogen sulfide generation

Engineering Contradiction:

Improveionic conductivityVSAvoidmoisture stability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies local quality by creating a concentration gradient of fluorine atoms within the solid electrolyte particles, where the surface region has higher fluorine concentration for moisture stability while the core maintains lower fluorine concentration for low resistance and high ionic conductivity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent creates a composite structure by incorporating fluorine-doped regions within the sulfide-based solid electrolyte matrix, forming a multi-phase material that combines the high ionic conductivity of sulfide with the moisture stability of fluorine-doped regions

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 electrolyte achieves excellent moisture stability by inhibiting the reaction with moisture while maintaining high ionic conductivity, reducing hydrogen sulfide generation and resistance.

Implementation Method 1

a surface portion that is formed on the core portion and includes fluorine-doped sulfide-based solid electrolyte particles

Methodology Applied

Scientific EffectDoping: Dopants

Implementation Method 2

a method of preparing the same, and an all-solid-state battery including the sulfide-based solid electrolyte

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 3

the surface portion includes a concentration gradient region in which a concentration of a fluorine (F) atom is decreased from a surface of the surface portion toward the core portion

Methodology Applied

Scientific EffectConcentration gradient: Density Gradient

Implementation Method 4

A solid electrolyte used in the all-solid-state battery is a material in a solid state which may conduct lithium ions in the battery

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Data Source

PatentUS20260066341A1Solid electrolyte, method of preparing the same, and all-solid-state battery including the solid electrolyte

Publication Date: 2026.03.05 LG CHEM LTD

AI summary

The present invention relates to a sulfide-based solid electrolyte having excellent moisture stability and ionic conductivity, a method of preparing the same, and an all-solid-state battery including the sulfide-based solid electrolyte, wherein the present invention provides a solid electrolyte which includes a core portion including sulfide-based solid electrolyte particles; and a surface portion which is formed on the core portion and includes fluorine-doped sulfide-based solid electrolyte particles, wherein the surface portion includes a concentration gradient region in which a concentration of a fluorine (F) atom is decreased from a surface of the surface portion toward the core portion, a method of preparing the same, and an all-solid-state battery including the solid electrolyte.