CO2-to-Formate Electrochemical Cell With Gas Diffusion Feed
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Solution Overview
Problem
Current technologies face challenges in scaling up CO2 electroreduction to ethylene due to poor solubility of CO2 in water and limited diffusivity towards the electrode, which hinders the efficient conversion of CO2 to valuable chemicals like formate.
Innovation Solution
A method involving a stack of electrochemical cells where the catholyte is recirculated until a desired concentration of formate is achieved, followed by separation from byproducts like carbonate salts, to produce formate salt from carbon dioxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CO2 electroreduction is scaled up to improve production capacity, then productivity increases, but CO2 solubility and diffusivity limitations worsen, reducing conversion efficiency
Solution Approach 1:
The patent introduces a gas diffusion layer as an intermediary component between the CO2 supply and the electrochemical reaction zone. This layer facilitates efficient CO2 transport to the catalyst surface, overcoming the solubility and diffusivity limitations in aqueous electrolytes. The gas diffusion layer acts as a mediator that enables high-rate CO2 delivery without being constrained by CO2's poor solubility in water, thus resolving the contradiction between scaling up production and maintaining conversion efficiency.
Solution Approach 2:
The patent creates a localized environment at the electrode interface where CO2 concentration is optimized for high-rate electroreduction. By using a gas diffusion layer, the system establishes a local zone with enhanced CO2 availability directly at the catalyst surface, while the bulk electrolyte maintains its aqueous properties. This local optimization of CO2 supply quality enables high productivity without requiring bulk changes to the electrolyte composition that would compromise other system properties.
2Device complexity
If conventional electrochemical cells are used, then device simplicity is maintained, but separation of formate from byproducts becomes difficult, reducing manufacturing precision
Solution Approach 1:
The patent segments the electrochemical cell into distinct functional zones: a gas diffusion layer compartment for CO2 delivery, an electrochemical reaction zone with catalyst-coated electrodes, and a product collection zone. This segmentation allows the formate produced in the reaction zone to be physically separated from carbonate byproducts and unreacted CO2. The segmented structure maintains relative device simplicity while enabling effective product separation, thus resolving the contradiction between structural simplicity and separation precision.
Solution Approach 2:
The patent extracts the formate product from the reaction mixture by utilizing the gas diffusion layer architecture, which allows selective removal of formate-containing electrolyte while retaining carbonate byproducts in the bulk solution. This extraction mechanism enables formate isolation without requiring complex separation equipment, maintaining device simplicity while achieving the necessary manufacturing precision for pure formate production.
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 approach enables the efficient production of formate from CO2, overcoming scalability issues by improving CO2 solubility and diffusivity, and facilitating the separation of formate from byproducts, thus enhancing the overall process efficiency.
Implementation Method 1
carbon dioxide diffuses from the dry compartment into the catholyte solution of the first wet compartment through the gas diffusion layer
Implementation Method 2
at least part of the carbon dioxide is transformed into formate by an electrochemical reaction
Data Source
AI summary
A method of producing formate salt from carbon dioxide; it includes receiving the carbon dioxide in a dry compartment, wherein the carbon dioxide diffuses from the dry compartment into a catholyte solution of a first wet compartment through the gas diffusion layer, and at least part of the carbon dioxide is transformed into formate by an electrochemical reaction, resulting in a formate-containing catholyte solution, whereby a carbonate byproduct is also produced from the carbon dioxide, remaining in the formate-containing catholyte solution; concentrating the formate in the formate-containing catholyte solution; separating the concentrated formate and the carbonate from the water of the formate-containing catholyte solution; and separating the carbonate from the formate to result in isolated formate salt.