Electrolyzer Membrane Electrode Assembly Salt Concentration
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Solution Overview
Problem
Electrolytic carbon dioxide reactors face challenges in balancing operating conditions such as reactant composition, electrical energy, and physical-chemical environments, affecting operating voltage, Faradaic yield, and product mix, particularly in achieving efficient carbon oxide reduction.
Innovation Solution
The use of membrane electrode assemblies (MEAs) with a carbon oxide reduction catalyst, a polymer electrolyte membrane, and a salt solution with specific ion concentrations, including alkali metal ions and bicarbonate, sulfate, or hydroxide ions, to optimize the reduction reaction and product selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If salt solution with high concentration is used, then ion concentration in MEA increases improving Faradaic yield, but osmotic pressure increases causing water loss from MEA
Solution Approach 1:
The patent optimizes salt concentration parameters within specific ranges (10 uM to 1M) to achieve the desired balance between ion concentration for high Faradaic yield and controlled osmotic pressure to prevent excessive water loss from the MEA
Solution Approach 2:
The polymer electrolyte membrane acts as an intermediary that selectively transports ions while restraining water molecules, allowing ion concentration to be maintained for high productivity while preventing excessive water loss through the membrane
2Power
If salt concentration in MEA is increased, then voltage efficiency improves, but osmotic pressure draws water from cathode to anode disrupting reaction balance
Solution Approach 1:
The patent controls salt concentration parameters to optimize voltage efficiency while maintaining reactant composition balance, using specific concentration ranges to prevent excessive osmotic water transfer that would disrupt the carbon oxide reduction reaction
Solution Approach 2:
The polymer electrolyte membrane serves as a mediator that enables ion transport for voltage efficiency while restraining excessive water transfer, thereby maintaining the stability of reactant composition at both electrodes
3Productivity
If PEM restricts water movement to maintain hydration, then carbon oxide reduction is promoted, but ion transport may be limited
Solution Approach 1:
The patent optimizes operating parameters including salt concentration and hydration levels to enable the PEM to simultaneously maintain sufficient hydration for carbon oxide reduction while allowing adequate ion transport through the membrane
Solution Approach 2:
The polymer electrolyte membrane acts as a selective intermediary that preferentially restrains water molecules while permitting ion transport, thereby promoting carbon oxide reduction without severely limiting ion availability
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 enhances Faradaic yield, voltage efficiency, and product selectivity, stabilizing the reactor's performance and increasing the production of carbon monoxide and hydrocarbons by maintaining optimal ion concentrations and hydration levels within the MEA.
Implementation Method 1
a polymer electrolyte membrane (PEM) layer disposed between, and in contact with, the cathode layer and the anode layer
Implementation Method 2
the concentration of salt or salt ions (accounting for multiple counterions donated by a multivalent ion) in the MEA is less than the concentration of salt in the salt solution
Implementation Method 3
a cathode layer comprising a carbon oxide reduction catalyst that promotes reduction of a carbon oxide
Implementation Method 4
electrolytic carbon oxide reduction field
Implementation Method 5
an anode layer comprising a catalyst that promotes oxidation of a water
Implementation Method 6
catalyst that promotes oxidation of a water
Implementation Method 7
salt ions from a salt solution that contacts the MEA, wherein the salt in the salt solution has a concentration of at least about 10 uM
Implementation Method 8
the concentration of salt or salt ions in the MEA is less than the concentration of salt in the salt solution
Data Source
AI summary
Disclosed are membrane electrode assemblies having a cathode layer comprising a carbon oxide reduction catalyst that promotes reduction of a carbon oxide; an anode layer comprising a catalyst that promotes oxidation of a water; a polymer electrolyte membrane (PEM) layer disposed between, and in contact with, the cathode layer and the anode layer; and a salt having a concentration of at least about 10 uM in at least a portion of the MEA.