Gas Diffusion Electrode Fluorine Gradient Water Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gas diffusion electrodes in fuel cells face challenges in achieving both flooding resistance and dry-out resistance, particularly at varying temperatures, which affects power generation performance.
Innovation Solution
A gas diffusion electrode with a microporous layer on an electrically conductive porous substrate, where the fluorine intensity is controlled across different regions to optimize hydrophobicity and water removal, using carbon black with specific structure indices and a fluororesin, ensuring balanced gas diffusivity and water management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydrophobic treatment is applied to improve water removal performance, then flooding resistance is improved, but gas diffusivity deteriorates due to pore closure
Solution Approach 1:
The patent applies local quality by creating a microporous layer with spatially varying fluorine intensity. The fluorine concentration is higher near the substrate interface and lower at the surface, creating different hydrophobicity zones. This gradient structure allows the deeper regions to effectively remove water while the surface region maintains gas diffusivity, resolving the contradiction between flooding resistance and gas supply.
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 a gas diffusion electrode with enhanced gas diffusivity and water removal performance, effectively preventing flooding and dry-out, thereby maintaining high power generation performance across a wide temperature range.
Implementation Method 1
a fluororesin is added as a hydrophobic resin in the microporous layer for imparting hydrophobicity to the microporous layer
Implementation Method 2
electrically conductive fine particles of carbon black etc. are dispersed
Implementation Method 3
gas diffusivity, electrical conductivity for collecting electricity generated in the catalyst layer, and water removal performance
Data Source
Figure 1
AI summary
The purpose of the present invention is to provide a gas diffusion electrode with good power generation performance as a fuel cell, which achieves both dry-up resistance and flooding resistance. In order to achieve the aforementioned purpose, the present invention is configured as described below. A gas diffusion electrode in which a microporous layer is provided on at least one surface of a conductive porous substrate, wherein the areas obtained by dividing the cross section perpendicular to the plane of the microporous layer into three equal parts in the thickness direction are a first area, a second area, and a third area, with respect to the conductive porous substrate side, the fluorine strength of the third area being 0.8 to 1.2 times the fluorine strength of the second area.