Porosity-Graded Catalyst Layer for Membrane Adhesion

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Solution Overview

Problem

Conventional techniques fail to adequately enhance the joining property between the polymer electrolyte membrane and the catalyst layer in water electrolysis devices, leading to potential peeling issues during operation.

Innovation Solution

An electrolyte membrane with a specific constitution, featuring a layer (A) containing a polymer electrolyte and a layer (B) with varying porosity at its interface regions, where the porosity on the layer (A) side is higher than on the opposite side, improving the joining property.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an adhesive layer is placed between the polymer electrolyte membrane and the catalyst layer to improve joining property, then the joining property is enhanced, but the device complexity increases and manufacturing difficulty arises

Engineering Contradiction:

Improvejoining propertyVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention removes the adhesive layer from the structure and instead modifies the catalyst layer itself by creating a porous intermediate region that provides inherent adhesion to the polymer electrolyte membrane, thereby eliminating the need for separate adhesive materials while maintaining joining property

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The catalyst layer is designed with non-uniform porosity distribution, where a porous intermediate region with higher porosity (30-70%) is created specifically at the interface with the polymer electrolyte membrane to enhance joining, while other regions maintain their original density and catalytic function

Inventive Principle:

Principle #3Local quality

2Reliability

If the catalyst layer porosity is increased to improve joining property with the polymer electrolyte membrane, then the joining property is enhanced, but the catalytic activity may be reduced due to decreased catalyst density

Engineering Contradiction:

Improvejoining propertyVSAvoidcatalytic activity

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The catalyst layer is designed with spatially varying porosity, where only the intermediate region at the membrane interface has high porosity (30-70%) to enhance joining, while the bulk catalyst region maintains lower porosity and high catalyst density to preserve catalytic activity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The catalyst layer is functionally segmented into different regions: a porous intermediate region for adhesion to the membrane, and a dense catalyst region for high catalytic activity, allowing each region to optimize its specific function without compromising the other

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP4545687A1Electrolyte membrane, electrolyte membrane with catalyst layer, transfer sheet used for producing same, membrane-electrode assembly, water electrolysis device, and method for manufacturing electrolyte membrane with catalyst layer

Publication Date: 2025.04.30 TORAY INDUSTRIES INC

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AI summary

An object of the present invention is to provide an electrolyte membrane having an excellent joining property between an electrolyte membrane and a catalyst layer. The present invention mainly relates to an electrolyte membrane including a layer (A) containing a polymer electrolyte, and a layer (B) on at least one of the faces of the layer (A), wherein porosity (X1) in an interface region of the layer (B), on the layer (A) side, is higher than porosity (X2) in another interface region of the layer (B), on the opposite side to the layer (A).