Interdigitated Microelectrodes for High-Resistivity Electrolytic Cells
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Solution Overview
Problem
Existing electrolytic cells with macroscopic electrodes are limited by mechanical tolerances and electrolyte resistivity, requiring low conductivity electrolytes and periodic regeneration, and fail to efficiently produce ozone and mixed oxidants from demineralized water.
Innovation Solution
Employing microelectrodes with micrometric gaps and mirror-like surfaces, coated with catalytic materials, allowing operation with high-resistivity electrolytes and producing ozone and mixed oxidants efficiently without regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrolytic cells are used with high-resistivity electrolytes, then the cell voltage can be limited within reasonable values at practically useful current density, but the recombination of ozone with hydrogen occurs frequently requiring periodic regeneration
Solution Approach 1:
The electrodes are segmented into multiple microelectrodes arranged in an interdigitated pattern on a single substrate. This segmentation increases the electrode surface area while maintaining compact dimensions, enabling high current density operation with high-resistivity electrolytes without requiring frequent regeneration
Solution Approach 2:
The invention transitions from conventional planar electrode arrangements to a three-dimensional interdigitated microelectrode structure. Multiple electrode fingers are stacked vertically and horizontally, creating multiple reaction zones within a compact footprint, which enhances productivity while maintaining reliability
2Power
If the interelectrodic gap is reduced to micrometric order, then the cell voltage can be limited within reasonable values at practically useful current density, but mechanical tolerances and diaphragm thickness prevent plates from being approached beyond a certain limit
Solution Approach 1:
Both anodic and cathodic microelectrodes are integrated on a single substrate rather than using separate plates. This merging eliminates the need for precise alignment between two plates and removes the constraint of mechanical tolerances and diaphragm thickness, enabling micrometric interelectrodic gaps to be achieved with high precision
Solution Approach 2:
The invention uses lithographic techniques to replicate precise microelectrode patterns on the substrate. This copying process ensures that the interelectrodic gaps are uniformly controlled at micrometric dimensions across the entire electrode array, overcoming the limitations of mechanical assembly tolerances
3Productivity
If rough cathode surfaces are used to increase hydrogen bubble size, then recombination of ozone with cathodically-evolved hydrogen is minimized, but the cathodes need to be periodically regenerated
Solution Approach 1:
The invention employs smooth microelectrode surfaces that do not require periodic regeneration. While rough surfaces might temporarily enhance bubble size, the smooth surfaces of the microelectrodes maintain consistent performance over extended periods, effectively replacing the need for regeneration cycles
Solution Approach 2:
The invention changes the surface roughness parameter from rough to extremely smooth (mirror-like). This parameter change, combined with the micrometric dimensions of the microelectrodes, fundamentally alters the bubble dynamics and reaction efficiency, enabling sustained high productivity without regeneration
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 microelectrodes enable high current density and efficient production of ozone and mixed oxidants, suitable for applications like sterilization and disinfection, even with low conductivity electrolytes, without the need for periodic regeneration.
Implementation Method 1
electrolytic cells provided with multiplicities of anode and cathode microelectrodes in a single plate mutually intercalated at distances of the micrometric order can operate even with aqueous electrolytes of very high resistivity (low conductivity) producing ozone and mixed oxidants
Implementation Method 2
the fraction of lost product due to recombination is not significant
Data Source
AI summary
An electrolytic cell equipped with microelectrodes for the generation of un-separated products and the method for obtaining it. The cell and the microelectrodes are obtained using a technology for the production of microelectromechanical systems (MEMS). The anodic and cathodic microelectrodes have an electrocatalytic coating and are mutually intercalated at an interelectrodic gap lower than 300 micrometres.