Gas Diffusion Electrode Segmentation for CO2 Electrolysis Stability
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Solution Overview
Problem
Conventional gas diffusion electrodes used in electrolysis systems for converting carbon dioxide to carbon monoxide suffer from insufficient long-term stability due to electrolyte penetration and salt excretion, known as salinization, which renders them unusable over time.
Innovation Solution
A gas diffusion electrode with two layers, where the first layer is an electrically conductive fabric embedded in a hydrophobic polymer matrix to prevent electrolyte penetration, and the second layer contains catalytically active particles with open porosity to facilitate chemical conversion at the interface between the layers, preventing further electrolyte penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional gas diffusion electrode with a single layer structure is used, then the electrode can conduct electricity and catalyze reactions, but the liquid electrolyte penetrates into the electrode and causes salinization, reducing long-term stability
Solution Approach 1:
The gas diffusion electrode is divided into two distinct layers: a first layer with electrically conductive fabric embedded in a hydrophobic polymer matrix for mechanical stability and electrolyte rejection, and a second layer with catalytically active particles for chemical conversion. This segmentation allows each layer to perform its specific function optimally while preventing the harmful effects of electrolyte penetration into the conductive fabric.
Solution Approach 2:
Different regions of the electrode are given different properties: the first layer is made hydrophobic to repel electrolyte, while the second layer is made hydrophilic to attract and absorb electrolyte for catalytic reactions. This local differentiation of properties ensures that electrolyte penetration is prevented in the conductive fabric region while enabling necessary electrochemical reactions in the catalytic region.
2Productivity
If the fabric is exposed to liquid electrolyte to enable catalytic reactions, then chemical conversion can occur, but salts are excreted from the electrolyte into the fabric matrix, causing salinization and rendering the electrode unusable
Solution Approach 1:
The hydrophobic polymer matrix acts as an intermediary barrier between the liquid electrolyte and the electrically conductive fabric. It prevents direct contact between the electrolyte and fabric, thereby preventing salt excretion into the fabric matrix, while still allowing the catalytic reactions to proceed in the second layer with proper electrolyte access.
3Reliability
If a hydrophobic polymer matrix is used to prevent electrolyte penetration, then salinization is prevented, but the fabric needs to remain electrically conductive for electron transport
Solution Approach 1:
The first layer is constructed as a composite material combining electrically conductive fabric (such as silver, titanium, or carbon fibers) embedded within a hydrophobic polymer matrix (such as polytetrafluoroethylene). This composite structure provides both the electrical conductivity needed for electron transport and the hydrophobic properties needed to repel electrolyte penetration, resolving the contradiction between these two requirements.
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 extends the service life of the gas diffusion electrode by preventing salinization and ensuring that the chemical conversion of carbon dioxide to carbon monoxide occurs effectively at the interface, maintaining electrode stability and efficiency.
Implementation Method 1
a hydrophobic polymer matrix that has a wetting angle with respect to water or the adjacent liquid electrolyte that is greater than 90°
Implementation Method 2
these catalytically active particles, in particular silver particles, are hydrophilic and absorb the liquid electrolyte and lead it to an interface between the first layer and the second layer
Implementation Method 3
the electrons for the conversion of the educt being made available through the electrically conductive tissue
Implementation Method 4
a second layer with an open porosity, which comprises catalytically active particles
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a gas diffusion electrode (2) having at least two layers (4, 6), of which a first layer (4) comprises an electrically conductive fabric (8), which is embedded at least in part in a hydrophobically acting polymer matrix (10), and a second layer (6) has an open porosity (12) which comprises catalytically acting particles (9) and has a thickness between 1 µm and 50 µm.