Electrospray Catalyst Layer Formation with Negative Pressure Control
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Solution Overview
Problem
Current methods for forming electrode catalyst layers in fuel cells and water electrolysis, such as screen printing and spray coating, are inefficient in reducing the use of precious metals like platinum and do not provide a uniform coating, limiting the performance of these systems.
Innovation Solution
The electrospray method is improved by using a catalyst ink containing a mixture of electrode catalyst, polymer electrolyte binder, and volatile organic compound or water, which is sprayed onto a polymer electrolyte membrane under controlled negative pressure, allowing for a more even and reduced platinum usage, with the binder coating the catalyst surface evenly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional coating methods (screen printing, spray coating) are used to form electrode catalyst layers, then the coating process is simple and fast, but the coating uniformity is poor and platinum usage cannot be reduced
Solution Approach 1:
The patent replaces conventional mechanical coating methods (screen printing, spray coating) with an electrospray method that uses electrical fields to atomize and deposit catalyst ink. This substitution enables precise control of coating uniformity while reducing platinum usage, as the electrospray process can form evenly distributed catalyst layers with controlled thickness and composition.
Solution Approach 2:
The patent employs parameter changes by controlling the electrospray voltage, substrate distance, and catalyst ink composition to optimize coating uniformity. By adjusting these parameters, the process achieves consistent catalyst layer formation with reduced platinum content, resolving the contradiction between coating quality and material efficiency.
2Quantity of substance
If the amount of platinum is reduced in electrode catalyst layers, then cost is reduced, but coating uniformity and performance are compromised
Solution Approach 1:
The patent applies local quality by ensuring uniform distribution of reduced platinum content across the entire electrode catalyst layer. The electrospray method deposits catalyst ink in a controlled manner, achieving homogeneous platinum distribution even at lower loadings, thus maintaining coating uniformity while reducing the total amount of platinum used.
Solution Approach 2:
By replacing mechanical coating methods with electrospray deposition, the patent achieves precise control over catalyst layer formation. This enables reduced platinum usage while maintaining uniform coating quality, as the electrical field-based deposition process can evenly distribute minimal platinum quantities across the substrate surface.
3Area of stationary object
If catalyst ink with low viscosity is used to improve sprayability, then coating coverage is improved, but catalyst ink drips during the process
Solution Approach 1:
The patent replaces gravity-dependent mechanical spraying with an electrospray system that uses electrical fields to control ink ejection. This substitution allows the use of low-viscosity catalyst ink for improved coating coverage while preventing dripping, as the electrical field precisely controls the atomization and deposition of the ink without relying on gravitational forces.
Solution Approach 2:
The patent employs parameter changes by adjusting the electrospray voltage and other process parameters to control the ejection of low-viscosity catalyst ink. This enables the system to achieve good coating coverage while preventing dripping, as the electrical field parameters can be optimized to match the low-viscosity ink properties and control the deposition process precisely.
4Quantity of substance
If electrospray method is applied to reduce platinum usage, then cost is reduced, but process control difficulty increases
Solution Approach 1:
The patent employs parameter changes by systematically optimizing electrospray voltage, substrate distance, and catalyst ink composition to simplify process control. These parameter adjustments enable reduced platinum usage while making the electrospray process easier to control, as the optimized parameters create a stable and reproducible deposition process.
Solution Approach 2:
The patent applies feedback control by monitoring and adjusting electrospray parameters based on coating quality and platinum deposition rates. This feedback mechanism enables reduced platinum usage while improving ease of operation, as real-time adjustments maintain optimal process conditions and simplify overall control despite the reduced material quantities involved.
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 enables the formation of a uniform electrode catalyst layer with reduced platinum usage, enhancing the performance of fuel cells and water electrolysis by ensuring complete surface coating and minimizing post-processing drying time, thus improving power generation and electrolysis efficiency.
Implementation Method 1
applying an electrospray voltage to the nozzle to cause electrospray of the catalyst ink through the tip end of the nozzle and thereby to form an electrode catalyst layer
Implementation Method 2
with the space inside of the air-tightly sealed container being conditioned to have a negative pressure of a level at which the catalyst ink cannot drip off from a conductive nozzle
Implementation Method 3
the volatile organic compound and/or water in the catalyst ink is volatilized and the fine mist is dried within the space immediately after electrospraying
Data Source
AI summary
A method for forming an electrode catalyst layer by putting catalyst ink within an insulative container having a conductive nozzle in communication with the interior of the container and applying an electrospray voltage to the nozzle to cause electrospray of the catalyst ink through the tip end of the nozzle and thereby to form an electrode catalyst layer, the method includes preparing catalyst ink containing a mixture of at least electrode catalyst, polymer electrolyte binder and volatile organic compound and/or water, putting the catalyst ink within the container with a space remaining inside thereof and air-tightly sealing the container, and electrospraying with the space inside of the air-tightly sealed container being conditioned to have a negative pressure of a level at which the catalyst ink cannot drip off from the nozzle.