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GDL

The gas diffusion layer is a key component in fuel cells and electrolyzers, located between the electrodes (cathode and anode) and the electrolyte membrane. The gas diffusion layer is a layered structure, usually composed of porous materials, such as carbon paper, carbon cloth, etc., with a large number of micropores or pores inside, which are used to provide gas diffusion channels and serve as a supporting material for the electrode. The gas diffusion layer is usually composed of a base layer (GDB) and a microporous layer (MPL). The base layer is in direct contact with the gas flow channel and is used for gas and liquid diffusion and conductivity; the microporous layer contains carbon powder and hydrophobic agent, which mainly manages the flow of liquid water and water vapor.

Product Recommendations

Classification of gas diffusion layer

Carbon fiber paper

Carbon fiber paper is a gas diffusion layer material widely used in PEMFC electrodes. It not only has a uniform porous thin layer structure, but also has excellent conductivity, chemical stability and thermal stability because the main raw material uses graphitized carbon fiber.

Carbon fiber woven cloth

Since carbon fiber paper is brittle and lacks flexibility, it is easily damaged during the preparation of electrodes. Therefore, carbon fiber woven cloth is also used as a gas diffusion layer substrate material in PEMFC electrodes. It has bending properties, which depends on the fiber structure and weaving process.

Carbon black paper

Carbon black paper used as the substrate of the gas diffusion layer is a sheet formed by evenly dispersing carbon powder and polymer binder and hot pressing to form a flat surface. The mass ratio of polymer to carbon powder is between 20:80 and 45:55.

Performance Requirements

Uniform porous structure, good air permeability;
Low resistivity, strong electron conduction ability;
Compact structure and flat surface, reducing contact resistance and improving conductivity;
Having certain mechanical strength, appropriate rigidity and flexibility, which is conducive to the production of electrodes and provides stability of electrode structure under long-term operation conditions;
Appropriate hydrophilic/hydrophobic balance to prevent excessive water from blocking pores and causing gas permeability to decrease;
Chemical stability and thermal stability;
Low manufacturing cost and high performance/price ratio