The porous transport layer (PTL) is typically located between the gas diffusion layer (GDL) and the electrode in a PEM electrolyzer, and is an important component for efficient mass transport and water management.

• Enables efficient mass transport of reactant and product gases
• Facilitates water management within the electrolyzer
• Helps maintain optimal pressure and gas distribution within the cell
• Provides mechanical support for the electrode assembly

Porosity, thickness, conductivity, mechanical properties and chemical stability are the main things to consider when choosing a Porous transport layer.

What is the difference between a PTL and a GDL?

While both a Gas Diffusion Layer (GDL) and a Porous Transport Layer (PTL) are porous materials used in fuel cells and electrolyzers, they are not exactly the same thing.

A GDL is a thin, porous layer that is typically placed between the electrode and the reactant gas flow field in a fuel cell or electrolyzer. Its primary function is to transport reactant gases to the electrode surface while also removing excess water produced during the electrochemical reaction. The GDL must also provide electrical conductivity between the electrode and the current collector, which collects the electrical current generated by the electrochemical reaction.

On the other hand, a PTL is a porous layer that is typically used to distribute the reactant gases uniformly across the surface of the electrode in a fuel cell or electrolyzer. The PTL can also serve as a barrier to prevent flooding of the electrode by excess reactant gas, as well as to manage water transport away from the electrode.

While the functions of the GDL and PTL are different, both materials are porous and typically made of similar materials, such as carbon fiber or paper, and both are important for efficient and effective operation of fuel cells and electrolyzers.

Both PTLs and GDLs are used in both fuel cells and electrolyzers. However, the specific materials used may vary depending on the application.

In general, the materials used for PTLs and GDLs in fuel cells and electrolyzers are similar, with carbon-based materials such as carbon paper, carbon cloth, or carbon fiber being the most common choices. However, the exact material and structure of the PTL and GDL can have a significant impact on the performance of the device, and different materials may be chosen depending on the specific requirements of the application.

For example, in high-temperature fuel cells such as solid oxide fuel cells (SOFCs), ceramic-based materials may be used as the PTL and GDL to withstand the high temperatures involved. In contrast, in low-temperature fuel cells and electrolyzers, carbon-based materials are typically used due to their high conductivity and compatibility with the catalyst materials used in these devices.

What is the difference between a PTL and an Electrode?

The porous transport layer (PTL) and the electrode are not the same thing, and they are separate material layers in a fuel cell or electrolyzer.

The electrode is typically made of a catalyst-coated porous layer, which is responsible for facilitating the electrochemical reaction. In a PEM electrolyzer, the anode and cathode electrodes are typically made of materials like titanium or nickel, and they are coated with a thin layer of platinum to act as a catalyst.

The PTL, on the other hand, is a thin, porous layer that is placed between the gas diffusion layer (GDL) and the electrode. Its primary function is to facilitate mass transport of reactant gases and water to the electrode surface, and to help manage the water content in the electrolyzer. The PTL is typically made of materials like carbon or graphite, and it can be coated with a hydrophobic material to repel water and prevent flooding.

So while the PTL and the electrode are both important components of an electrolyzer, they are separate layers made of different materials with distinct functions.

Is electrical conductivity important for the PTL?

Yes, electrical conductivity is an important property for the Porous Transport Layer (PTL) in a fuel cell or electrolyzer.

The PTL is typically located between the electrode and the gas diffusion layer (GDL), and its primary function is to distribute the reactant gases uniformly across the electrode surface while also managing water transport away from the electrode. Additionally, the PTL must provide good electrical conductivity between the electrode and the current collector, which collects the electrical current generated by the electrochemical reaction.

The electrical conductivity of the PTL is important because it directly affects the efficiency of electron transfer between the electrode and the current collector. If the PTL has poor electrical conductivity, there will be increased resistance to the flow of electrons, resulting in reduced performance and efficiency of the fuel cell or electrolyzer. Therefore, it is important to select a PTL material that has good electrical conductivity to ensure efficient operation of the fuel cell or electrolyzer.

All values are indicative and subject to tolerance