Modular CO2 Electrolyzer Stack for High-Pressure Gas Conversion
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Solution Overview
Problem
Existing CO2 electrolyzers face limitations in conversion rate due to low CO2 solubility in water, mass-transport issues, and inefficiencies in product selectivity, making them unsuitable for industrial-scale applications.
Innovation Solution
A modular, multi-cell electrolyzer stack with a novel architecture that allows for high current density, selective product formation, and operation at elevated pressures, using a two-component bipolar plate assembly and Ti-frit anode structure to enhance reaction efficiency and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CO2 is fed through a liquid catholyte in conventional electrolyzers, then CO2 can be supplied to the electrode, but CO2 solubility in water is low leading to current limitation and low conversion rate
Solution Approach 1:
The invention changes the physical state of CO2 from dissolved gas in liquid catholyte to direct gaseous feed through the gas diffusion layer. This parameter change from liquid-phase to gas-phase delivery overcomes the solubility limitation and enables high CO2 concentration at the electrode surface, achieving high conversion rates
Solution Approach 2:
The invention extracts CO2 directly from the gas phase through the gas diffusion layer without requiring dissolution in liquid catholyte. This removes the limiting factor of CO2 solubility in water and enables direct electrochemical reduction at high current densities
2Productivity
If conventional single-cell electrolyzers are used, then the structure is simple, but the production scale is limited and not suitable for industrial applications
Solution Approach 1:
The invention divides the electrolyzer into multiple cells (2-10 cells) connected in series, with each cell containing cathode, anode, and membrane components. This segmentation enables scalable production while maintaining manageable complexity through modular design, suitable for industrial applications
Solution Approach 2:
The bipolar plates serve multiple functions: electrical connection between cells, structural support, and gas distribution. This multi-functionality reduces the number of separate components needed and simplifies the overall system architecture for multi-cell configurations
3Productivity
If high current density is achieved for high conversion rate, then productivity increases, but product selectivity becomes difficult to control
Solution Approach 1:
The invention uses different catalysts in different locations (cathode for CO2 reduction, anode for water oxidation) with specific properties optimized for their respective functions. This local quality differentiation enables high current density while maintaining product selectivity through catalyst-specific reaction pathways
Solution Approach 2:
The membrane separates the cathode and anode compartments, controlling ion transport and maintaining pH gradients that provide feedback control over reaction conditions. This enables selective product formation by maintaining optimal local environments for desired reactions even at high current densities
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 electrolyzer stack achieves high conversion rates and selectivity for gas-phase products, enabling scalable and flexible production suitable for industrial applications, with the ability to switch between series and parallel operations based on product needs.
Implementation Method 1
a membrane electrode assembly (MEA) comprising a cation-exchange membrane
Implementation Method 2
cathode electrocatalyst layer in direct contact with the cathodic GDL and the membrane, wherein the cathode electrocatalyst layer comprises a catalyst for the electrochemical reduction of carbon dioxide to carbon monoxide
Implementation Method 3
CO2 gas is also fed through the GDL
Implementation Method 4
electrolysis of gaseous carbon dioxide
Data Source
Figure 1~2B
Figure 3A~3B
Figure 4
AI summary
The present invention relates to the field of converting gaseous carbon dioxide to gas-phase products at elevated pressures with high conversion rates via electrolysis performed by a novel multi-stack CO2 electrolyzer cell (100") that has a novel gas and fluid flow architecture formed in bipolar plate assemblies used to construct individual stacks (40) of the cell (100").