Fuel Cell Microporous Layer Binder With Reduced Fluorine Content
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Solution Overview
Problem
Conventional gas diffusion layers for fuel cells rely on fluorine-containing polymers, which pose environmental concerns and reduce mechanical stability and electrical conductivity due to high binder content, necessitating a fluorine-free or low-fluorine binder solution that maintains mechanical stability and adhesion while optimizing pore structure.
Innovation Solution
Employing a polymeric binder comprising fluorine-free, high-temperature-resistant polymers like polyaryl ether ketones, polyphenylene sulfides, and polysulfones for the microporous layer, which reduces fluorine content and enhances mechanical stability and adhesion without increasing the binder volume, allowing for controlled pore creation without thickness or weight gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If fluorine-containing polymers are used as binders in the microporous layer, then adhesion and hydrophobicity are improved, but environmental harm increases and mechanical stability decreases due to high binder content requirements
Solution Approach 1:
The invention changes the chemical composition parameter of the binder from fluorine-containing polymers to fluorine-free high-temperature-resistant polymers. This parameter change eliminates the environmental harm associated with fluorine-containing polymers while maintaining the necessary binding properties through the use of alternative polymer materials that resist thermal degradation at fuel cell operating temperatures.
Solution Approach 2:
The invention uses composite materials by combining fluorine-free high-temperature-resistant polymers with conductive particles (such as carbon black or graphite) to create a microporous layer binder that achieves both mechanical stability and electrical conductivity without relying on fluorine-containing polymers.
2Strength
If binder content in the microporous layer is increased to improve adhesion, then adhesion strength is improved, but electrical conductivity and mass transport deteriorate
Solution Approach 1:
The invention changes the physical and chemical parameters of the binder material itself - using fluorine-free high-temperature-resistant polymers with optimized molecular weight, glass transition temperature, and rheological properties. This allows achieving sufficient adhesion strength with lower binder content, thereby maintaining electrical conductivity and mass transport properties.
Solution Approach 2:
The invention applies the binder locally and optimally within the microporous layer structure, ensuring that the binder is positioned where it is most needed for adhesion while maintaining porosity and conductivity in other regions. The binder content is optimized locally rather than uniformly distributed at high concentrations throughout.
3Strength
If MPL layer penetrates deeper into the GDL substrate to improve adhesion, then adhesion strength is improved, but mass transport is reduced due to increased areal weight
Solution Approach 1:
The invention changes the binder material parameters to achieve sufficient adhesion strength with reduced binder content and shallower penetration depth. The fluorine-free high-temperature-resistant polymers provide strong binding properties that allow the MPL layer to maintain adequate adhesion without needing to penetrate deeply into the GDL substrate, thus preserving mass transport pathways.
4Reliability
If conventional fluorine-containing polymers are used to ensure hydrophobicity, then hydrophobicity is maintained, but environmental sustainability deteriorates
Solution Approach 1:
The invention changes the chemical composition of the hydrophobic material from fluorine-containing polymers to fluorine-free alternatives. The high-temperature-resistant polymers used have inherent hydrophobic properties or can be modified to achieve the necessary water repellency without relying on environmentally harmful fluorinated compounds.
Solution Approach 2:
The invention replaces expensive and environmentally problematic fluorinated polymers with more sustainable, readily available fluorine-free polymer materials that can be processed and disposed of more environmentally friendly, while maintaining the required functional performance.
Data Source
AI summary
The present invention relates to a gas diffusion layer for fuel cells comprising a microporous layer with a polymeric binder that is fluorine-free or has a lower proportion of fluorine-containing polymers compared to conventional binders, as well as the gas diffusion layers obtainable according to this method and a fuel cell containing such a gas diffusion layer.