Stable Catalyst Ink Formulations for Electrospun Fibrous Mats
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Solution Overview
Problem
The instability of electrospinning ink formulations for platinum catalysts used in proton exchange membrane fuel cells leads to inconsistent and reproducible results, particularly in industrial-scale production, due to viscosity changes and potential chemical reactions, hindering the production of uniform fibers and increasing manufacturing costs.
Innovation Solution
A stable ink formulation comprising a metal supported on a carrier, an ionomer, and an electrospinning polymer selected from halogen-comprising polymers, such as polyvinylidene fluoride, which is electrospun using a nozzle-free process to produce a fibrous mat for use in membrane electrode assemblies, reducing the need for constant parameter adjustments and improving fiber uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrospinning ink formulations with platinum catalyst are used, then fiber production can proceed, but the ink exhibits chemical and physical instability leading to viscosity changes and inconsistent results
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the electrospinning ink formulation. Specifically, it selects polymers with particular functional groups (carboxylic acid, hydroxyl, or amine groups) that chemically interact with platinum catalyst particles to prevent oxidation. The formulation also specifies particular solvent systems (water-alcohol mixtures) and pH ranges (3-9) to maintain stability. These parameter adjustments resolve the contradiction by making the ink formulation stable without compromising fiber uniformity, as the modified composition prevents viscosity changes during storage and processing.
2Productivity
If needle-based electrospinning systems are used, then fiber production is possible, but scaling up production is difficult and productivity is limited
Solution Approach 1:
The patent extracts the needle component from the electrospinning system by employing a nozzle-free electrospinning apparatus. This extraction eliminates the scaling limitations inherent in needle-based systems, as multiple needles would be required to increase production and each needle represents a potential clogging point. The nozzle-free system allows for continuous, high-volume ink delivery without the mechanical constraints of needles, thereby simultaneously improving productivity and ease of manufacture for large-scale production.
3Quantity of substance
If particle containing solutions are electrospun through needles, then catalyst can be delivered, but needle clogging issues occur
Solution Approach 1:
The patent removes the needle from the electrospinning system entirely by using a nozzle-free apparatus. This extraction eliminates the clogging problem that occurs when particle-containing catalyst solutions are forced through narrow needle openings. The nozzle-free system delivers the catalyst-containing ink through a broader opening, allowing particles to pass through without obstruction, thereby maintaining both catalyst delivery quantity and process consistency without interruptions from clogging.
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 stable ink formulation enables consistent and reproducible production of electrospun fibrous mats with improved catalytic activity and durability, reducing manufacturing costs and enhancing the performance and longevity of fuel cells.
Implementation Method 1
Electrospinning inks for the present purposes comprise a catalyst on a carrier, an ionomer, an electrospinning polymer and a solvent
Implementation Method 2
Without wishing to be bound by theory, it is possible that platinum on a carbon carrier might be able to oxidize alcohols, which may be used as solvent in electrospinning inks
Data Source
AI summary
The present invention relates to stable catalyst ink formulations comprising am electrospinning polymer selected from halogen-comprising polymers. The present invention further relates to electrospinning of such ink formulation, to the so-obtained electrospun fibrous mat as well as to articles comprising such electrospun fibrous mat.