CO2 Electrolyzer Liquid Passing Member for Voltage Stability
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Solution Overview
Problem
Existing electrolytic cells for carbon dioxide face challenges in stabilizing cell voltage due to CO2 gas entering the cathode solution flow path, leading to increased solution resistance and fluctuations, especially when producing liquid compounds like methanol or ethanol, as these gases do not easily pass through anion exchange membranes.
Innovation Solution
Incorporating a liquid passing member between the cathode and the cathode solution flow path, which allows the cathode solution to pass through while blocking CO2 gas, thereby reducing gas component entry into the solution flow path and maintaining a stable cell voltage by facilitating the output of liquid products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CO2 gas is supplied to the cathode at high pressure or in large amounts, then the production rate of carbon compounds increases, but CO2 gas enters the cathode solution flow path, increasing solution resistance and causing cell voltage fluctuations
Solution Approach 1:
A gas diffusion layer is introduced as an intermediary between the CO2 gas supply and the cathode solution flow path. This layer allows selective transport: CO2 gas molecules can diffuse through it to reach the cathode for carbon compound production, while the cathode solution is prevented from mixing with the gas phase. This resolves the contradiction by enabling high productivity through adequate CO2 supply while maintaining voltage stability by preventing gas entrainment in the solution flow path.
Solution Approach 2:
The cathode structure is designed with spatially differentiated regions: a gas diffusion layer facing the CO2 gas supply and a catalyst layer facing the cathode solution. This local differentiation allows the gas side to receive high amounts of CO2 for high productivity while the solution side maintains stable ionic conductivity, preventing the contradiction between high gas flow rates and voltage stability.
2Reliability
If an anion exchange membrane is used to prevent CO2 gas from entering the cathode solution flow path, then cell voltage stability improves, but nonionic liquid components such as methanol or ethanol cannot be taken out to the cathode solution flow path
Solution Approach 1:
The cathode assembly is segmented into distinct functional layers: a gas diffusion layer for gas transport, a catalyst layer for carbon compound synthesis, and a porous support structure. This segmentation allows the gas diffusion layer to prevent gas entry into the solution while the porous catalyst layer enables liquid product diffusion to the solution flow path, resolving the contradiction between voltage stability and liquid product output.
Solution Approach 2:
A porous catalyst layer with controlled pore size and distribution is used in the cathode. The pore structure allows selective transport: it prevents CO2 gas bubbles from entering the cathode solution flow path (maintaining voltage stability) while permitting nonionic liquid products like methanol and ethanol to diffuse from the catalyst sites to the solution (enabling productivity).
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 configuration reduces solution resistance and cell voltage fluctuations, enhancing the stability and efficiency of the electrolytic cell by preventing gas mixing into the cathode solution flow path and allowing efficient passage of liquid products, thus improving the sustainability and performance of the electrolytic device.
Implementation Method 1
a liquid passing member disposed between the cathode and the cathode solution flow path and having a pore allowing the cathode solution to pass through while holding the cathode solution
Implementation Method 2
a cathode to reduce carbon dioxide and thus produce a carbon compound
Implementation Method 3
an anode to oxidize water or a hydroxide ion and thus produce oxygen
Data Source
AI summary
An electrolytic cell for carbon dioxide of an embodiment includes: an anode part including an anode to oxidize water or a hydroxide ion and thus produce oxygen and an anode solution flow path to supply an anode solution to the anode; a cathode part including a cathode to reduce carbon dioxide and thus produce a carbon compound, a cathode solution flow path to supply a cathode solution to the cathode, and a liquid passing member disposed between the cathode and the cathode solution flow path and having a pore allowing the cathode solution to pass through while holding the cathode solution; and a separator to separate the anode part and the cathode part from each other.