Platinized Nanostructured Membrane Mitigates Hydrogen Crossover

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Solution Overview

Problem

High operating pressures in proton exchange membrane (PEM) based water electrolyzers lead to hydrogen crossover from the cathode to the anode, resulting in efficiency losses and unsafe hydrogen-oxygen mixtures exceeding the lower explosive limit.

Innovation Solution

A water electrolyzer design featuring a membrane with a platinized nanostructured layer comprising close-packed whiskers coated with platinum or platinum oxide, combined with a cathode catalyst of metallic Pt or Pt oxide and an anode catalyst comprising at least 95% Ir and Ir oxide, which mitigates hydrogen crossover through catalytic recombination of hydrogen and oxygen within the membrane while maintaining low ionic resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If higher operating pressures are applied to the cathode to increase hydrogen production efficiency, then productivity is improved, but hydrogen crossover to the anode increases causing safety hazards and efficiency losses

Engineering Contradiction:

Improvehydrogen production efficiencyVSAvoidhydrogen crossover

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a platinized nanostructured layer that catalyzes the recombination of crossed-over hydrogen with oxygen to form water, converting the harmful hydrogen crossover into a beneficial recombination reaction that eliminates safety hazards while maintaining high operating pressures for productivity

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If a thicker membrane is used to reduce hydrogen crossover, then safety is improved, but ionic resistance increases reducing efficiency

Engineering Contradiction:

Improvehydrogen crossoverVSAvoidionic resistance

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The patent applies local quality by introducing a platinized nanostructured layer at specific locations within the membrane structure, creating regions with different functional properties - the platinized regions provide catalytic activity for hydrogen recombination while the bulk membrane maintains low ionic resistance for efficient proton transport

Inventive Principle:

Principle #3Local quality

3Ease of manufacture

If conventional catalyst layers are used, then manufacturing is simpler, but the membrane cannot be made thinner while maintaining catalytic activity

Engineering Contradiction:

Improvecatalyst layer preparationVSAvoidmembrane thickness

Core Design Contradiction:

Ease of manufactureVSLength of stationary object

Solution Approach 1:

The patent employs parameter changes by transforming the catalyst from conventional dispersed particles to a structured platinized nanostructured layer with high surface area and enhanced catalytic activity per unit volume, enabling thinner membrane design while maintaining or improving catalytic performance

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 solution effectively reduces hydrogen crossover, maintaining low ionic resistance and ensuring safe operation by facilitating the recombination of hydrogen and oxygen, thereby enhancing the efficiency and safety of the water electrolysis process.

Implementation Method 1

membranes according to the present disclosure can effectively mitigate hydrogen crossover in a proton exchange membrane (PEM) water electrolyzer via catalytic recombination of H2 (g) and O2 (g) within the membrane

Methodology Applied

Scientific EffectCatalysis: Catalysis

Implementation Method 2

a membrane having first and second opposed major surfaces and comprising: a first membrane layer comprising a first ion-conductive polymer; a second membrane layer comprising a second ion-conductive polymer

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 3

providing an electrical current with sufficient potential difference across the membrane to convert at least a portion of the water to hydrogen and oxygen on the cathode and anode, respectively

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Data Source

PatentUS11560632B2Membrane, membrane electrode assembly, and water electrolyzer including the same

Publication Date: 2023.01.24 3M INNOVATIVE PROPERTIES CO

AI summary

A water electrolyzer comprises a membrane, a cathode and an anode. The membrane comprises a first membrane layer comprising a first ion-conductive polymer, a second membrane layer comprising a second ion-conductive polymer, and a platinized nanostructured layer disposed between the first layer and the second layer. The platinized nanostructured layer comprises close-packed whiskers having at least one of platinum or platinum oxide disposed thereon. The cathode is disposed on the membrane and comprises a first catalyst consisting essentially of both metallic Pt and Pt oxide. The anode is disposed on the opposite surface of the membrane and comprises a second catalyst comprising at least 95 percent by weight of collectively metallic Ir and Ir oxide, calculated as elemental Ir, based on the total weight of the second catalyst, wherein at least one of metallic Ir or Ir oxide is present. Membranes and methods of making them are also disclosed.