Laminated Electrolysis Membrane for Radical Durability and Gas Barrier

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Solution Overview

Problem

Existing anion conducting membranes used in water electrolysis suffer from poor durability against OH radicals and high gas permeability, particularly in gas pressurized-type water electrolysis, leading to potential gas crossover issues.

Innovation Solution

A laminated membrane structure comprising a hydrocarbon-based polymer layer with ionic groups and perfluoro-carbon polymer layers, which enhances radical durability and reduces gas permeability, utilizing specific polyarylene polymers and radical scavengers to improve performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a perfluoro-sulfonic acid polymer membrane is used to achieve high gas permeability, then gas transport efficiency is improved, but gas crossover risk increases and radical durability deteriorates

Engineering Contradiction:

Improvegas transport efficiencyVSAvoidgas crossover prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The membrane is divided into multiple functional layers: a perfluoro-sulfonic acid polymer layer for ion conduction and gas transport, and a polyphenylene-based polymer layer for radical resistance and gas barrier properties. Each layer performs its specific function, allowing the membrane as a whole to achieve both high gas transport efficiency and low gas crossover.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite membrane structure combining perfluoro-sulfonic acid polymer and polyphenylene-based polymer. The perfluoro-sulfonic acid polymer provides high ion conductivity and gas permeability, while the polyphenylene-based polymer contributes radical stability and reduced gas permeability, creating a material that balances gas transport efficiency with gas crossover prevention.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a polyphenylene-based polymer membrane is used to achieve excellent alkali durability, then chemical stability is improved, but radical durability against OH radicals deteriorates

Engineering Contradiction:

Improvealkali durabilityVSAvoidradical durability

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The perfluoro-sulfonic acid polymer layer acts as an intermediary between the polyphenylene-based polymer layer and the harsh electrochemical environment. It provides a protective interface that enhances overall radical durability while allowing the polyphenylene-based polymer to maintain its alkali durability advantages.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

By combining polyphenylene-based polymer (excellent alkali durability) with perfluoro-sulfonic acid polymer (good radical resistance), the composite membrane achieves superior performance in both alkali durability and radical durability, overcoming the limitations of either single material alone.

Inventive Principle:

Principle #40Composite materials

3Productivity

If gas pressurized-type water electrolysis is implemented to improve production efficiency, then hydrogen production efficiency is improved, but the risk of gas crossover through the membrane increases

Engineering Contradiction:

Improvehydrogen production efficiencyVSAvoidgas crossover risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The membrane structure is designed to maintain low gas permeability through the polyphenylene-based polymer layer even under pressurized conditions. The layered structure and material properties are optimized to resist gas crossover at the operating pressures of gas pressurized-type water electrolysis, enabling high productivity without excessive gas crossover risk.

Inventive Principle:

Principle #35Parameter changes

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 proposed membrane structure achieves excellent radical durability and low gas permeability, suitable for water electrolysis applications, improving the efficiency and safety of hydrogen production.

Implementation Method 1

it has been known that in this perfluoro-sulfonic acid polymer, sulfonic acid groups gather like a reversed micelle and thereby form microscopic voids (a cluster structure)

Methodology Applied

Scientific EffectCluster structure formation:

Implementation Method 2

The proposed membrane structure achieves excellent radical durability and low gas permeability

Methodology Applied

Scientific EffectPermeation resistance: Permeation

Implementation Method 3

the layer A contains a hydrocarbon-based polymer (a) which has an ionic group and may be fluorine-substituted; and each of the layers B1 and B2 contains a perfluoro-carbon polymer (b) having an ionic group

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Data Source

PatentEP4644122A1Membrane, membrane electrode assembly, and water electrolysis device

Publication Date: 2025.11.05 NIPPON KAYAKU CO LTD

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AI summary

A membrane having excellent radical durability and low gas permeability, a membrane electrode assembly including the membrane, and a water electrolysis apparatus are provided. A membrane having a laminated structure including a layer B1, a layer A, and a layer B2 in this order, in which the layer A contains a hydrocarbon-based polymer (a) which has an ionic group and may be fluorine-substituted, and each of the layers B1 and B2 contains a perfluoro-carbon polymer (b) having an ionic group.