This is a low porosity thermally platinized sintered titanium fiber felt product with good electrical conductivity.   Metallic or thermally platinized titanium fiber felts are primarily used in standard PEM electrolyzer single cells and stacks as the flow field or diffuser material, particularly on the oxygen (anode) side. Electrolyzer hardware cannot use carbon-based gas diffusion layers (GDLs) at the anode because carbon will immediately oxidize to CO₂ (if the medium is acidic) or carbonate ions (if the medium is basic) during the electrolysis reaction. Thermally platinized titanium fiber felt becomes an ideal candidate as the diffusion medium for PEM electrolyzer applications. Thermally platinized titanium fiber felt also provides electrical contact between the anode catalyst layer and bipolar plate or current collector at the anode side.

Our thermally platinized titanium felts are produced from small-diameter titanium fibers that has been compressed and flattened, then annealed (i.e., sintered).  This ensures a smooth, flat surface suitable for use in electrolyzers. They then go through our proprietary themal platinization process to extend the lifetime of titanium fiber felt greatly. 

While most industrial applications operate their PEM electrolyzers in the anode-fed mode and this product makes an excellent diffusion medium for the oxygen evolution electrode, it can also be used as an ideal diffusion medium for researchers conducting cathode-fed PEM electrolyzer research.

For unitized fuel cells or electrolyzers or regenerative electrochemical devices systems, titanium fiber felt can be used at anode or cathode as the diffusion medium.  Electrochemical oxygen concentrators, electrochemical inerters, certain classes of batteries (such as redox flow batteries) can also benefit from this product as the diffusion medium regardless of the nature of the reactants.

Thermally platinized titanium fiber felt products will have higher mechanical strength compared to the electrochemically platinized titanium fiber felt products and hence, they are easy to handle during cell assembly without physical breakages.

When Should I use a Thermally Platinized Titanium Fiber Felt?
Presence of pure oxygen does have an impact on the titanium based substrates such as titanium felt if the PEM electrolyzer is being operated at high pressures (1 bar to 3 bars).  The untreated titanium surface will quickly form an electrically insulated oxide layer (TiO₂) on the surface of the of the small-diameter fibers under high O₂ pressures. This oxide coating will eventually affect the efficiency of the overall system and it will increase the interfacial resistance in the cell, lowering the electrochemical performance (an increase in the cell voltage if the cell is operated under constant current mode, or a decrease in the current if the cell is operated under constant voltage mode).  

The forming of this oxide coating can be prevented by applying a gold or platinum coating.  The surface platinization of titanium generates a coating that is electrically conductive and chemically stable under regular electrolysis conditions. Thereby, extending the lifetime of the titanium, which is ideal for applications that demand high performance and long lifetime.  Prevention of the formation of TiO₂ will greatly stabilize the electrochemical performance of the electrolyzer or the intended electrochemical device.

Function of the Platinum Coating for This Product
The main functionality of the platinum coating is to maintain the electrical conductivity of the substrate itself for demanding applications such as longer operational lifetime or pressurized electrolyzer (up to 100 psi) applications.  In the industry, it has been observed that thermally platinized titanium fiber felt products can be used at the anode side of the PEM electrolyzer hardware at such pressure values.  Higher pressures than 100 psi would create safety issues for titanium fiber felt substrate in presence of pure oxygen even if the environment is fully wetted.  Platinum coating does not have a continuous layer for its structure.  The estimated platinum metal loading for this product is approximately 60-80 micrograms per cm2 of the substrate's physical dimensions.

Catalytic Activity of the Platinum Coating for this Product
The platinum coating in this product does not have any catalytic activity.  Typical catalysis requires the catalytically active material of interest to have sufficient surface defects (or high surface area) and also sufficient loading for the catalytically active component.  Platinum particles in the themal coating does not have the essential surface defects and has zero catalytic activity for most chemical or electrochemical reactions including oxygen evolution reaction and hence, this product should not be used for catalysis reactions or applications that require catalytically active materials.  

• Porosity: ~53-56%
• Thickness: 0.2-0.3 mm (uncompressed height)
• Dimensions: Various sizes available.

This product is usually available as in-stock item, otherwise the lead times would be around 2-3 weeks.