Gas Diffusion Electrode Water-Repellent Substrate Flooding
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Solution Overview
Problem
Existing gas diffusion electrodes in fuel cells face challenges with flooding due to water vapor condensation, which reduces gas supply to the catalyst layer, and the microporous layer's poor adhesion to the conductive substrate, leading to decreased power generation and durability issues.
Innovation Solution
A gas diffusion electrode with a microporous layer containing electrically conductive microparticles and a water-repellent resin, applied to a thin, highly porous electrically conductive porous substrate, ensuring good adhesion and reduced flooding, manufactured using a method that involves applying the microporous layer coating liquid from below and subsequent drying and sintering to prevent penetration into the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a microporous layer coating liquid is applied to a thin and highly porous electrically conductive porous substrate to enhance gas diffusivity, then gas diffusion capability is improved, but the coating liquid penetrates into the substrate and blocks pores, reducing gas diffusion and contaminating the manufacturing process
Solution Approach 1:
The substrate is subjected to water-repellent treatment before applying the microporous layer coating liquid. This preliminary action creates a barrier that prevents the coating liquid from penetrating into the substrate pores, while still allowing the substrate's high gas diffusion capability to be maintained. The water-repellent treatment is performed in advance to avoid the harmful effect of coating liquid penetration.
2Object-generated harmful factors
If the microporous layer is applied to improve water drainage and suppress flooding, then water drainage capability is enhanced, but the adhesion between the microporous layer and substrate is poor, leading to durability issues
Solution Approach 1:
The contact angle of the substrate is controlled to be 70° or less through water-repellent treatment. This parameter change optimizes the wettability of the substrate surface, enabling the microporous layer coating liquid to adhere properly while still providing effective water drainage. By precisely controlling the contact angle parameter, both adhesion and water drainage capability are achieved.
3Force
If the substrate is made thinner and more porous to facilitate gas diffusion, then gas diffusivity is improved, but the substrate becomes more vulnerable to coating liquid penetration and manufacturing defects
Solution Approach 1:
The substrate is pre-treated with water-repellent coating before the microporous layer application. This preliminary anti-action creates a protective barrier that counteracts the tendency of the coating liquid to penetrate into the thin, highly porous substrate. The water-repellent treatment is applied in advance to prevent the harmful effect before it can occur.
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 solution provides excellent gas diffusivity, high-output power generation, improved durability, and reduced defects, while maintaining high productivity and preventing contamination of the manufacturing process.
Implementation Method 1
a gas diffusion electrode including an electrically conductive porous substrate that has been subjected to a water-repellent treatment is used
Implementation Method 2
a coating liquid for forming a microporous layer (so-called microporous layer coating liquid) penetrates into the substrate having a small thickness and a high porosity
Implementation Method 3
At a low temperature, such water vapor is condensed into water drops, blocking pores of the gas diffusion electrode
Implementation Method 4
applying the microporous layer coating liquid from below and subsequent drying and sintering to prevent penetration into the substrate
Data Source
AI summary
A gas diffusion electrode and a method for manufacturing the same, the gas diffusion electrode being used for a fuel cell and configured by forming a microporous layer containing conductive microparticles and water-repellent resin on at least one surface of a conductive porous base material, wherein the gas diffusibility in the thickness direction thereof is 30% or more, the conductive porous base material has a sliding angle of 70° or less and a porosity of 80% or more, and the microporous layer has a thickness of 10-50 μm inclusive, and a porosity of 60-95% inclusive.