Fuel Cell Catalyst Layer Preventing Polymer Runoff
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Solution Overview
Problem
Conventional fuel cells using platinum carbon black catalyst layers face issues with proton conductive polymers, such as Nafion, running off due to moisture generated during operation, leading to catalyst layer deterioration and reduced electromotive force.
Innovation Solution
A catalyst layer structure with a carrying layer composed of a proton conduction layer and an adhesive layer, where the proton conduction layer is formed using a polymer with acidic side chains and the adhesive layer uses a polymer with benzene rings and basicity, securely binding the proton conduction layer to carbon, preventing runoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a proton conductive polymer such as Nafion is used in the catalyst layer, then proton conduction is enabled and electric power generation is achieved, but the polymer runs off due to moisture produced during operation
Solution Approach 1:
The catalyst layer is divided into multiple functional layers: a proton conductive polymer layer for proton conduction, a carbon black layer for catalyst support, and an adhesive layer for binding. This segmentation allows each layer to perform its specific function while preventing the proton conductive polymer from running off, as it is now confined to its designated layer rather than being mixed with other components.
Solution Approach 2:
An adhesive layer is introduced as an intermediary between the proton conductive polymer and the carbon black catalyst support. This adhesive layer (containing polyvinylidene fluoride and/or polytetrafluoroethylene) acts as a mediator that prevents the proton conductive polymer from running off while maintaining proton conduction capability and catalyst functionality.
2Productivity
If the catalyst layer is made with platinum carbon black and proton conductive polymer, then electrochemical reaction is enabled, but the catalyst layer deteriorates due to polymer runoff
Solution Approach 1:
By segmenting the catalyst layer into distinct functional layers (proton conductive polymer layer, carbon black layer, and adhesive layer), the invention prevents mixing and runoff of components during operation. This maintains the integrity of the catalyst layer structure, ensuring long-term durability while sustaining electric power generation capability.
Solution Approach 2:
The adhesive layer serves as a stable intermediary that anchors the proton conductive polymer to the carbon black support, preventing polymer runoff that would otherwise lead to catalyst layer deterioration. This ensures both sustained productivity and reliability over time.
3Reliability
If the proton conductive polymer has high wettability due to acidic functional groups, then proton conduction is facilitated, but the polymer is more prone to running off due to water generation
Solution Approach 1:
The adhesive layer containing polyvinylidene fluoride and/or polytetrafluoroethylene acts as a protective intermediary that prevents water from causing the proton conductive polymer to run off. This adhesive layer is resistant to water and maintains the structural integrity of the catalyst layer even in the presence of water generated during electrochemical reactions.
Solution Approach 2:
The catalyst layer is formulated as a composite material system combining the proton conductive polymer, carbon black, and adhesive materials (polyvinylidene fluoride and/or polytetrafluoroethylene). This composite structure leverages the complementary properties of each material: proton conduction from the polymer, catalyst support from carbon black, and water resistance from the adhesive materials, thereby preventing polymer runoff while maintaining high proton conduction efficiency.
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 configuration effectively prevents proton conduction polymer runoff and maintains catalyst layer integrity, enhancing the fuel cell's performance and durability by maintaining electromotive force and reducing maintenance needs.
Implementation Method 1
the lower layer forming an adhesive layer which binds the proton conduction layer and the carbon to each other
Implementation Method 2
the upper layer forming a proton conduction layer which conducts protons generated in the catalyst particles or protons to be supplied to the catalyst particles therethrough
Implementation Method 3
the catalyst layer is a portion where electrons and protons are generated from a negative electrode active material, electrons and protons are made to react with a positive electrode active material
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
Provided is a catalyst layer constituting body which can prevent runoff of a proton conductive polymer from a catalyst layer even when moisture is generated by an operation of a fuel cell. In a catalyst layer constituting body of a fuel cell where catalyst particles are carried on carbon, the catalyst particles are carried on the carbon by way of a carrying layer constituted of two upper and lower layers, the upper layer of the carrying layer is formed by using a polymer having proton conductivity, the upper layer forming a proton conduction layer which conducts protons generated in the catalyst particles or protons to be supplied to the catalyst particles therethrough, and the lower layer of the carrying layer is formed using a polymer having affinity with both the proton conduction layer and the carbon, the lower layer forming an adhesive layer which bonds the proton conduction layer and the carbon to each other.