What Is an EDI Titanium Electrode?
An EDI titanium electrode is a coated titanium electrode used in EDI modules to conduct DC current and support the electrochemical processes involved in continuous ion removal.
EDI electrodes typically use platinum, Ru-Ir MMO, Ir-Ta MMO or Pt-based coatings, depending on the module design and operating conditions.
Proper electrode selection considers current density, water chemistry, operating voltage, coating performance and service life to ensure reliable EDI operation.
Why Is Coating Selection Important for EDI Electrodes?
The Right Coating Depends on Your EDI Operating Conditions
No single coating fits every EDI application. Selection depends on polarity, current density, voltage, water chemistry, module design and service life.
Coating Options: Ru-Ir MMO · Ir-Ta MMO · Platinum · Pt-based hybrid
Ehisen provides customized electrodes based on drawing, coating requirements and actual EDI operating conditions.
Ru-Ir, Ir-Ta, Platinum or Hybrid Coating: Which Is Better for EDI?
There is no single coating that is best for every EDI module. The right coating depends on electrode polarity, current density, operating voltage, water chemistry, electrode reaction and required service life.
Ru-Ir MMO
A mature MMO coating with high electrocatalytic activity and relatively low overpotential.
Best evaluated for: catalytic activity, electrode reaction, current density and water chemistry.
Ir-Ta MMO
An MMO coating designed for anodic stability and corrosion resistance, particularly under demanding oxygen-evolution conditions.
Best evaluated for: operating potential, current density, water chemistry and service life.
Platinum
Pt-coated titanium offers high chemical stability and clean electrochemical characteristics. Performance and lifetime depend on Pt thickness, coating process and operating conditions.
Best evaluated for: Pt thickness, current density, polarity, coating adhesion and service life.
Pt-Based Hybrid
A multi-layer or combined coating system designed to balance catalytic activity, corrosion resistance, coating stability and service life.
Best evaluated for: electrode reaction, module design, performance targets and lifetime.
| Coating System | Main Characteristics | Potential Advantages | Key Factors |
| Ru-Ir MMO | Catalytic MMO coating | High catalytic activity | Polarity, reaction, current density, water chemistry |
| Ir-Ta MMO | Stable MMO coating | Anodic stability, corrosion resistance | Potential, current density, water chemistry, lifetime |
| Platinum | Metallic Pt coating on Ti | Chemical stability, clean electrochemical performance | Pt thickness, process, current density, lifetime |
| Pt-Based Hybrid | Multi-layer coating structure | Balances performance, stability and lifetime | Module design, reaction, performance target, lifetime |
The best coating is not necessarily the most expensive one. It is the coating system that best matches the actual EDI operating conditions.
A Result We Saw in a Real EDI Project
In one EDI project, Ehisen supplied a single-side Ru-Ir MMO coated titanium anode plate based on the customer's requirements.
Comparative testing showed a noticeable difference in product-water resistivity between the Ti/Ru-Ir MMO and Ti/Pt electrodes under the customer's operating conditions.
| Electrode Type | Product-Water Resistivity |
| Ti/Pt | ≈17 MΩ·cm |
| Ti/Ru-Ir MMO | ≈10 MΩ·cm |
The Ru-Ir MMO electrode operated normally, but Ti/Pt achieved higher product-water resistivity in this particular EDI module.
This result does not mean Pt is always better than MMO. It demonstrates that electrode coating selection should be based on the actual EDI module design, operating conditions and product-water performance target.
Actual EDI performance matters more than coating type alone.
What Parameters Matter When Selecting an EDI Titanium Electrode?
Current Density Matters,Current alone is not enough to specify an EDI electrode.
The same 10 A applied to electrodes with different effective coated areas will produce different current densities and electrochemical loads.
| Parameter | Why It Matters |
| Electrode Dimensions & Coated Area | Determines module compatibility and electrochemical load |
| Polarity | Defines the electrode's electrochemical environm |
| Current / Current Density | Determines the actual load on the coating |
| Operating Voltage | Defines the electrical operating conditions |
| Water Conductivity & Chemistry | Influences electrode reactions and coating stability |
| pH & Temperature | Affect electrochemical reactions and coating durability |
| Coating Type & Loading | Influences performance, lifetime and cost |
| Product-Water Quality | Defines the required electrode performance |
| Expected Service Life | Helps determine the coating design and loading |
Current Density = Current ÷ Effective Coated Area
Therefore, EDI electrode selection should consider current, effective coated area and current density together.
How Does Ehisen Select a Coating for an EDI Electrode?
Our approach: Match the coating system to the actual EDI operating conditions and performance requirements-not simply to a predetermined coating.
| Project Type | Existing EDI Electrode | New / Optimized EDI Electrode |
|---|---|---|
| Starting Point | Existing electrode specification | New design or performance improvement |
| Required Information | Drawing · Titanium grade · Coating type · Coating thickness/loading · Dimensions | Module design · Polarity · Electrode reaction · Effective area · Current density · Voltage · Water chemistry |
| Performance Target | Manufacture to confirmed specifications | Product-water quality · Service life · Electrode performance |
| Coating Selection | According to customer specification | Evaluated according to actual operating conditions |
| Coating Options | Customer-specified | Ru-Ir MMO · Ir-Ta MMO · Pt/Ti · Pt-Based Hybrid |
| Sample Evaluation | Available when required | Available for performance evaluation |
| Ehisen Approach | Manufacture to specification | Match the coating to the application |
Common EDI Electrode Problems We Pay Attention To
Understanding the Root Cause Before Changing the Coating
| Common Issue | Possible Factors |
| Increasing Electrode Voltage | Coating degradation · Surface contamination · Scaling · Substrate passivation · Electrical contact · Module conditions |
| Short Electrode Life | Unsuitable coating · Excessive current density · Insufficient coating loading · Aggressive operating conditions · Poor adhesion |
| Surface Deposits / Scaling | Water chemistry · Hardness · Ionic composition · pH · Electrode reactions |
| Coating Damage | Surface preparation · Coating process · Thermal treatment · Adhesion · Handling |
Our Approach：Diagnose the operating conditions → Identify the root cause → Optimize the coating and electrode design
Coating performance depends on more than precious-metal loading. Substrate preparation, coating structure, manufacturing process and actual EDI operating conditions all affect electrode durability.
Custom EDI Titanium Electrode Manufacturing
Custom EDI Titanium Electrode Manufacturing
Ehisen manufactures customized titanium electrodes for EDI modules based on customer drawings, samples and operating requirements.
Customization Options
Titanium plates, mesh and machined electrodes
Ru-Ir MMO, Ir-Ta MMO, Platinum and Pt-based hybrid coatings
Single-side or double-side coating
Customized coated area, precious-metal loading and Pt thickness
Custom holes, slots and electrical connection structures
Manufacturing Support
Prototype → Small Batch → Volume Production
For replacement projects, provide your existing electrode drawing or sample.
For new EDI designs, we can evaluate the coating system and electrode structure according to your operating conditions.
From Titanium Substrate to Finished EDI Electrode
EDI electrode performance depends not only on the coating, but also on titanium substrate preparation and coating processing.
Proper titanium surface preparation is critical for coating adhesion and long-term stability.
Therefore, electrodes with the same coating type and precious-metal loading may still show different performance due to differences in surface preparation, coating structure and manufacturing process.
Quality Control for EDI Titanium Electrodes
Dimensional Inspection - Check critical dimensions, holes, slots, thickness, and connection features per approved drawing.
Surface Inspection - Inspect for contamination, coating defects, and mechanical damage.
Coating Evaluation - Assess composition, thickness, loading, or distribution per coating system and customer requirements.
Batch Consistency - Control manufacturing and inspection parameters per confirmed specifications for repeat orders.
Electrochemical & Lifetime Evaluation - Conduct electrochemical performance or accelerated lifetime testing as needed, useful for comparing coating systems, evaluating process consistency, and studying coating durability.
Key Note: Accelerated test results should not be equated with actual service life. Real operating life depends on current density, water chemistry, operating temperature, voltage, and operating mode.
For EDI Module Manufacturers and Procurement Teams
For long-term EDI module production, customers may also need to evaluate whether the electrode manufacturer can maintain consistent dimensions, coating specifications and production processes across repeat orders.
Ehisen supports:
Prototype
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>>
Customer Testing
2
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Specification Confirmation
3
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Batch Production
4
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Repeat Supply
5
For an existing product, we can work according to approved drawings and technical specifications.
For a new project, prototype electrodes with different coating structures or coating parameters can be discussed for comparative testing.
This allows the final electrode specification to be based on actual EDI module performance rather than material assumptions alone.
What Information Should You Send for an EDI Electrode Quotation?
For an accurate quotation and technical evaluation, please provide the available information:
| Information |
|
| Electrode Design | Drawing / dimensions · Titanium grade · Coated area · Single-/double-side |
| Coating Requirements | Ru-Ir MMO / Ir-Ta MMO / Pt / Hybrid · Loading or Pt thickness |
| Electrical Conditions | Polarity · Operating / maximum current · Voltage · Current density |
| Water Conditions | Conductivity · Water chemistry · pH · Temperature |
| Performance Requirements | Product-water quality · Expected service life |
| Production Requirements | Prototype quantity · Estimated annual volume |
Don't Have All the Data?
That's okay. Send us your existing electrode drawing, sample or available operating data. We can identify the missing information needed for evaluation and quotation.
Frequently Asked Questions About EDI Titanium Electrodes
What coating is used for EDI titanium electrodes?
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EDI titanium electrodes can use Ru-Ir MMO, Ir-Ta MMO, platinum or specially designed hybrid coating systems. There is no universal coating for every EDI module. Selection depends on electrode polarity, electrochemical reaction, current density, operating voltage, water chemistry, product-water requirements and expected service life.
Is platinum better than Ru-Ir MMO for EDI?
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Not necessarily. In one Ehisen customer project, a Ti/Pt electrode achieved approximately 17 MΩ·cm product-water resistivity while a Ti/Ru-Ir MMO electrode achieved approximately 10 MΩ·cm under the customer's comparative test conditions. This result was specific to that module and operating condition and should not be treated as a universal performance ratio. The appropriate coating should be selected according to actual module requirements.
What platinum thickness should be used for an EDI electrode?
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There is no single Pt thickness suitable for every EDI module. Platinum thickness should be determined together with current density, polarity, operating voltage, water chemistry, required service life and manufacturing process. Specifying Pt thickness without considering these parameters can result in either unnecessary cost or insufficient durability.
Is electroplated platinum different from brush-coated platinum?
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Yes. The two processes can produce differences in coating structure, morphology and electrochemical characteristics. The appropriate process should be evaluated according to electrode efficiency, required Pt thickness, adhesion, durability, module conditions and cost.
Does more precious metal always mean longer electrode life?
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No. Precious-metal loading is important, but electrode life also depends on coating composition, substrate pretreatment, adhesion, current density, operating potential, water chemistry, temperature and operating time.
Looking for an EDI Electrode Supplier?
Developing a new EDI module or looking for an electrode supplier?
Simply send us your drawing, sample, or operating data. Our engineers will evaluate your requirements and recommend the right electrode solution.
Available Coatings:
Ru-Ir MMO · Ir-Ta MMO · Pt/Ti · Pt-Based Hybrid Coatings
Support:
Custom Design · Prototype Testing · Mass Production
Our address
Shaanxi Ehisen Technology Co., Ltd.
Phone Number
+86 18710841426
elowenyu@ehisen-anode.com
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