Polymer-Coated Sulfide Solid Electrolyte for Moisture Stability

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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 and deteriorating their performance.

Innovation Solution

A composite solid electrolyte is developed with a polymer coating layer having a Mooney viscosity of 30 to 110, formed on sulfide-based solid electrolyte particles, using polymers like acrylonitrile and butadiene monomers to enhance atmospheric stability and chemical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If sulfide-based solid electrolyte is used to achieve high ionic conductivity, then ionic conductivity is improved, but atmospheric stability deteriorates due to high reactivity with moisture

Engineering Contradiction:

Improveionic conductivityVSAvoidatmospheric stability

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies composite materials by combining sulfide-based solid electrolyte particles with a polymer coating layer. The sulfide-based solid electrolyte provides high ionic conductivity, while the polymer coating layer (using materials like polyacrylonitrile, polybutadiene, or their copolymers) provides atmospheric stability and moisture resistance. This composite structure allows the electrolyte to maintain both high ionic conductivity and reliability in atmospheric conditions.

Inventive Principle:

Principle #40Composite materials

2Strength

If sulfide-based solid electrolyte is used to achieve high ductility, then mechanical flexibility is improved, but chemical resistance deteriorates due to reaction with moisture generating hydrogen sulfide

Engineering Contradiction:

ImproveductilityVSAvoidchemical resistance

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent uses the polymer coating layer as an intermediary between the sulfide-based solid electrolyte and the external environment. This coating layer acts as a protective barrier that prevents direct contact between moisture and the sulfide-based solid electrolyte, thereby preventing the generation of hydrogen sulfide gas while maintaining the mechanical flexibility and ductility of the underlying sulfide-based solid electrolyte.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If polymer coating layer is formed to improve atmospheric stability, then chemical resistance is improved, but ionic conductivity may deteriorate due to coating layer interference

Engineering Contradiction:

Improveatmospheric stabilityVSAvoidionic conductivity

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by creating a polymer coating layer with specific local properties (appropriate thickness, porosity, and material composition) that provides atmospheric stability without significantly impeding ionic conductivity. The coating layer is designed to be sufficiently thin and potentially porous to allow lithium ion transport while providing the necessary protective function against moisture and oxygen.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250372698A1Composite Solid Electrolyte and All-Solid-State Battery Comprising the Same

Publication Date: 2025.12.04 LG CHEM LTD

AI summary

A composite solid electrolyte includes sulfide-based solid electrolyte particles, and a polymer coating layer formed on the sulfide-based solid electrolyte particles, wherein the polymer coating layer includes a polymer having a Mooney viscosity (ML1+4, 100° C.) of from 30 to 110. An all-solid-state battery including the composite solid electrolyte is also provided.