Pulsed Electrolyte Flow Electrodeposition for Uniform Porous Catalysts
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Solution Overview
Problem
The challenge in manufacturing porous electrodes lies in achieving a substantially uniform thickness of the catalyst layer across the interior surfaces of a porous substrate due to limited throwing power during electrodeposition.
Innovation Solution
A method involving electrolyte flow through the porous substrate combined with pulsed electrical pulses is employed to electrodeposit a catalyst layer, where the electrolyte flow partially restores the local concentration of catalyst ions during inter-pulse intervals, ensuring uniform thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electrodeposition is used to coat a porous substrate, then a catalyst layer can be formed, but the thickness is non-uniform across the interior surfaces due to limited throwing power
Solution Approach 1:
The patent applies periodic pulsed electrodeposition where the power supply delivers current in discrete pulses separated by inter-pulse intervals. During pulses, catalyst ions are deposited; during intervals, electrolyte flow restores ion concentration. This periodic cycling enables uniform thickness distribution throughout the porous substrate by preventing ion depletion that causes non-uniformity in continuous deposition.
Solution Approach 2:
The patent introduces forced electrolyte flow through the porous substrate during the inter-pulse intervals. This hydraulic action actively transports fresh catalyst-containing electrolyte into the pores, restoring the local ion concentration that was depleted during the deposition pulse. The flow rate and timing are controlled to match the consumption rate, ensuring uniform replenishment throughout the substrate.
2Productivity
If continuous electrodeposition is applied, then deposition speed is high, but catalyst ion concentration depletes locally leading to non-uniform layer thickness
Solution Approach 1:
The pulsed deposition mode alternates between high-rate deposition phases (pulses) and recovery phases (intervals). During pulses, high current density achieves rapid catalyst layer formation. During intervals, current is reduced or stopped while electrolyte flow replenishes ion concentration, preventing depletion-induced non-uniformity. This cycling maintains both high productivity and uniformity.
Solution Approach 2:
The electrolyte flow is activated during the inter-pulse intervals before the next deposition pulse begins. This preliminary replenishment of catalyst ions ensures that when the high-rate deposition resumes, sufficient ions are available throughout the porous substrate, preventing the concentration depletion that would otherwise cause non-uniform thickness and limit further deposition rate.
3Productivity
If high current density is used to increase deposition rate, then productivity improves, but throwing power decreases causing non-uniform thickness distribution
Solution Approach 1:
The pulsed regime allows brief periods of high current density for rapid deposition, followed by recovery intervals that reset the ion concentration field. This temporal separation enables the system to tolerate higher peak current densities without the cumulative ion depletion that would cause non-uniformity, effectively decoupling deposition rate from throwing power limitations.
Solution Approach 2:
Forced electrolyte flow during inter-pulse intervals actively counteracts the concentration gradients created by high current density pulses. The hydrodynamic transport delivers fresh ions to regions that would otherwise be depleted, maintaining uniform concentration fields even during high-rate deposition, thereby preserving throwing power at elevated productivity levels.
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 consistent electrodeposition of a catalyst layer with uniform thickness across the entire surface of the porous substrate, improving the throwing power and process capability, allowing for effective manufacturing of porous electrodes.
Implementation Method 1
providing an electrolyte flow through the porous substrate... the electrolyte flow at least partially restores the local concentration of the ions at the porous substrate interface
Implementation Method 2
applying electrical pulses between an anode and the porous substrate at inter-pulse intervals to electrodeposit the ions of the at least one catalyst material on the porous substrate
Data Source
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AI summary
Example embodiments relate to a method and a system for electrodepositing a catalyst layer on a porous substrate. The method comprises, during an electrodeposition period, providing an electrolyte flow (320) through the porous substrate (312), wherein the electrolyte (302) comprises ions of at least one catalyst material; applying electrical pulses (341 - 344) between an anode (301) and the porous substrate (312) at inter-pulse intervals (352) to electrodeposit the ions of the at least one catalyst material on the porous substrate, thereby forming the catalyst layer and decreasing a local concentration of the ions at the porous substrate interface (311) during the respective electrical pulses (341 - 344); and wherein the electrical pulses are applied such that the electrolyte flow (320) at least partially restores the local concentration of the ions at the porous substrate interface (311) during the respective inter-pulse intervals (352).