Durable, low loading oxygen evolution reaction catalysts and methods of forming such catalysts
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Solution Overview
Problem
Current PEM electrolyzers face inefficiencies due to the lack of optimized interfaces for catalyst, water, electrical conductor, proton transport, and gas transport, leading to high costs and limited iridium availability, which affects the operating lifetime and performance of oxygen evolution reaction catalysts.
Innovation Solution
The use of atomic layer deposition (ALD) to apply a thin, nanometer-scale layer of active catalysts like iridium oxide on conductive substrates, such as nanofiber cores, to enhance catalyst utilization and reduce loading while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional random coating method is used to apply catalyst and ionomer onto PEM and GDL, then the interface structure is formed, but the electrical conductivity is poor and the density of 5-way junctions is low
Solution Approach 1:
The patent applies ionomer and catalyst to the GDL before assembling the electrolyzer cell, ensuring proper interface formation and electrical connectivity is established in advance. This preliminary application allows optimization of the 5-way junction density and electrical conductivity before the cell is sealed and operated.
Solution Approach 2:
The patent focuses on creating localized regions of high 5-way junction density at the PEM-GDL-catalyst interfaces where they are most needed for efficient proton transport, electron conduction, and gas bubble removal. The random coating method is replaced with targeted application strategies that concentrate functional features at critical interface locations.
2Reliability
If high loading of iridium catalyst is used to ensure sufficient catalytic activity and lifetime, then the oxygen evolution reaction performance is maintained, but the cost increases and global availability becomes constrained
Solution Approach 1:
The patent changes the physical and chemical parameters of the catalyst layer through controlled application methods and ionomer-catalyst ratio optimization, achieving higher catalytic activity per unit mass of iridium. By adjusting parameters such as layer thickness, particle size distribution, and ionomer content, the catalyst utilization efficiency is improved, allowing reduced iridium loading while maintaining performance.
Solution Approach 2:
The patent creates composite catalyst layers combining iridium oxide particles with ionomer matrices and conductive support structures. This composite approach distributes the catalytic function across multiple materials, reducing reliance on high iridium loading while maintaining overall catalytic activity through synergistic interactions between components.
3Stability of the object's composition
If the anode GDL is made of platinum-coated titanium to withstand oxidizing acidic environment, then the chemical stability is achieved, but the cost increases due to expensive platinum
Solution Approach 1:
The patent applies protective coatings and catalyst layers locally at specific regions of the GDL where chemical stability is most critical, such as at the PEM interface and catalyst support zones. Rather than uniformly coating the entire GDL surface, the treatment is concentrated at locations experiencing highest oxidative stress, reducing overall platinum usage while maintaining chemical stability where needed.
Solution Approach 2:
The patent explores alternative materials that may not require expensive platinum coatings, potentially using shorter-lived but cheaper materials in non-critical regions, or designing the GDL structure to minimize exposure to oxidizing conditions through improved flow field design and gas bubble removal strategies.
4Productivity
If the interface is optimized to increase density of 5-way junctions and improve electrical conductivity, then the catalyst utilization improves, but the manufacturing complexity increases
Solution Approach 1:
The patent simplifies interface optimization by performing catalyst and ionomer application on the GDL before cell assembly, allowing standard manufacturing processes to create the desired interface structure without requiring complex in-situ adjustments during cell fabrication. This preliminary preparation step decouples interface optimization from final cell assembly complexity.
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
This approach significantly reduces the amount of iridium required by maximizing the active surface area and minimizing volume, leading to improved electron transport and catalyst durability, potentially decreasing iridium loading by a factor of 5 to 10 without compromising performance.
Implementation Method 1
depositing an active catalyst composition onto a surface of the supporting substrate via atomic layer deposition (ALD)
Data Source
AI summary
The following disclosure relates to catalyst compositions for electrochemical cells and their methods of making. In one example, the method includes providing a supporting substrate and depositing an active catalyst composition onto a surface of the supporting substrate via atomic layer deposition (AID). A catalyst composition includes a conductive substrate and an active catalyst deposited on a surface of the conductive substrate via atomic layer deposition.