Gas Diffusion Electrode Base with Optimized Carbon Powder
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Solution Overview
Problem
Existing gas diffusion electrode substrates with microporous layers have insufficient surface roughness reduction, leading to potential damage to electrolyte membranes in polymer electrolyte fuel cells, despite efforts to decrease carbon powder particle size.
Innovation Solution
The use of carbon powder with specific dibutyl phthalate oil absorption (DBP oil absorption) within an appropriate range to reduce the secondary particle size, thereby minimizing surface roughness of the microporous layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the particle size of carbon powder is decreased to reduce surface roughness, then the surface roughness is supposedly reduced, but the coating liquid infiltrates into the carbon sheet and surface roughness is not sufficiently reduced
Solution Approach 1:
The invention changes the particle size parameter of carbon powder to an optimal range (D50: 0.5-2.0 μm, D90: 2.0-5.0 μm) to balance surface roughness reduction with preventing coating liquid infiltration. This parameter optimization resolves the contradiction by finding the sweet spot where surface smoothing occurs without causing excessive infiltration that would prevent proper microporous layer formation.
2Reliability
If the particle size of carbon powder is decreased to improve microporous layer smoothness, then the durability of electrolyte membrane is improved, but the surface roughness is not sufficiently reduced
Solution Approach 1:
The invention optimizes the particle size distribution parameters (D50 and D90 values) to achieve the dual goal of reducing surface roughness for membrane protection while maintaining sufficient smoothness for durability. The controlled particle size range ensures that carbon powder particles are small enough to smooth the surface but not so small that they cause infiltration issues, thereby resolving the contradiction between surface quality and membrane durability.
Solution Approach 2:
The invention uses composite carbon powder with specific particle size distribution characteristics (combining different particle sizes with D50 of 0.5-2.0 μm and D90 of 2.0-5.0 μm) to achieve both surface smoothing and adequate structural integrity. This composite approach allows the microporous layer to have low surface roughness for membrane protection while maintaining the necessary porosity and mechanical properties for durability.
Data Source
Figure 1
AI summary
The purpose of the present invention is to provide: a method for producing a gas diffusion electrode base which enables the achievement of a gas diffusion electrode base that has a microporous layer with small surface roughness and is not susceptible to damaging an electrolyte membrane; and a gas diffusion electrode base that has a microporous layer with small surface roughness and is not susceptible to damaging an electrolyte membrane. For the purpose of achieving the above-described purpose, the present invention has the configuration described below. Namely, a specific gas diffusion electrode base which has a carbon sheet and a microporous layer, and wherein the carbon sheet is porous and the DBP oil absorption of a carbon powder contained in the microporous layer is 70-155 ml/100g.