Layered Solid Electrolyte Membrane for Strength and Ionic Conductivity

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Solution Overview

Problem

Existing all-solid-state batteries face challenges in maintaining both high ionic conductivity and mechanical strength, with potential side reactions occurring at the interface between the solid electrolyte membrane and the negative electrode, which degrade battery performance.

Innovation Solution

A solid electrolyte membrane is designed with two layers, where the first layer contains a lower weight percentage of fibrous binder compared to the second layer, and both layers are manufactured without solvents, forming a strong, solvent-free structure that minimizes side reactions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the binder content in the solid electrolyte layer is increased to improve mechanical strength, then the strength is improved, but the ionic conductivity is reduced

Engineering Contradiction:

Improvemechanical strengthVSAvoidionic conductivity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The solid electrolyte membrane is divided into multiple layers with different binder contents. The first layer (in contact with negative electrode) has low binder content (0.1-5 wt%) to maintain high ionic conductivity and prevent side reactions, while the second layer has higher binder content (1-20 wt%) to provide mechanical strength and handling stability. This segmentation allows each layer to optimize for its specific function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the solid electrolyte membrane are assigned different binder concentrations based on local requirements. The interface region with the negative electrode uses low binder content to minimize harmful side reactions, while regions requiring structural support use higher binder content. This local optimization resolves the contradiction between strength and ionic conductivity.

Inventive Principle:

Principle #3Local quality

2Reliability

If a liquid electrolyte is used to secure the ionic conductivity of the solid electrolyte, then the ionic conductivity is improved, but the strength is reduced

Engineering Contradiction:

Improveionic conductivityVSAvoidmechanical strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The harmful liquid electrolyte component is extracted and removed from the solid electrolyte membrane structure. Instead of using liquid electrolyte to enhance ionic conductivity, the invention uses carefully controlled solid electrolyte compositions with minimal binder content to achieve both high ionic conductivity and mechanical strength through the layered structure.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If the binder content is reduced to improve ionic conductivity, then the ionic conductivity is improved, but the strength is reduced

Engineering Contradiction:

Improveionic conductivityVSAvoidmechanical strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention combines multiple solid electrolyte layers with different properties into a single integrated membrane structure. The low-binder layer contributes ionic conductivity while the high-binder layer contributes mechanical strength, and together they form a unified membrane that achieves both high ionic conductivity and adequate strength.

Inventive Principle:

Principle #5Merging (Combining)

4Reliability

If a solid electrolyte membrane with binder is used to ensure safety, then the safety is improved, but side reactions occur at the interface with the negative electrode

Engineering Contradiction:

ImprovesafetyVSAvoidside reactions

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The interface region with the negative electrode is specifically optimized with low binder content (0.1-5 wt%) to minimize harmful side reactions, while other regions of the membrane maintain higher binder content for structural integrity and safety. This local optimization at the critical interface prevents degradation while preserving overall membrane safety.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The first solid electrolyte layer with low binder content acts as a protective barrier that prevents side reactions between the binder and the negative electrode. By placing this low-reactivity layer in direct contact with the negative electrode, the invention preemptively blocks harmful interactions before they can occur.

Inventive Principle:

Principle #9Preliminary anti-action

Data Source

PatentUS20260074279A1Solid electrolyte membrane, method for manufacturing the same, and all-solid-state battery comprising the same

Publication Date: 2026.03.12 LG ENERGY SOLUTION LTD

AI summary

Disclosed is a solid electrolyte membrane, a method for manufacturing the same, and an all-solid-state battery including the same. More specifically, the solid electrolyte membrane includes a first solid electrolyte layer including a first solid electrolyte and a first fibrous binder and a second solid electrolyte layer including a second solid electrolyte and a second fibrous binder, stacked adjacent to each other, wherein the weight of the first fibrous binder relative to the total weight of the first solid electrolyte layer is less than the weight of the second fibrous binder relative to the total weight of the second solid electrolyte layer. Since the weight of a first fibrous binder included in the first solid electrolyte layer is less than the weight of the second fibrous binder included in the second solid electrolyte layer, the strength may be improved without lowering the ionic conductivity of the solid electrolyte membrane.