Gas Diffusion Layer
The gas diffusion layer (GDL) is a core component of a fuel cell and is commonly composed of non-woven carbon fiber paper or woven carbon cloth. The main function of GDL is to provide conductivity, and help gases to come in contact with the catalyst. The GDL works as a support for the catalyst layer, provides good mechanical strength and easy gas access to the catalyst and improve the electrical conductivity.
ElectroChem offers different kinds of GDL materials, e.g. carbon fiber paper, carbon cloth, Carbon Fiber Paper with CNT on the surface, and Carbon NanoTube (CNT) paper as it is, and/or with various enhancements. These are also available with Hydrophobic treatment as well as Carbon MicroPorous Layer (CMPL).
A hydrophobic treatment to GDL enables improved water transport. In PEM fuel cells, specifically water retention can result in lower power generation. These GDLs are treated with Teflon in order to make the material hydrophobic and improve water transport.
The purpose of the Carbon Microporous Layer (CMPL) is to minimize the contact resistance between the GDL and catalyst layer, limit the loss of catalyst to the GDL interior and help to improve water management as it provides effective water transport. CMPL treatment is especially recommended for use with CCM ( Catalyst Coated Membrane).
ElectroChem offers a range of GDL products, including carbon fiber papers, carbon cloth. PTFE coating for hydrophobicity and coating carbon microporous layers is also available.
The CNT-GDL is a sheet of nonwoven carbon paper with Carbon Nanotube( CNT) grown on the surface of every fiber. CNTs are shown to be more corrosion resistant. These CNTs are vertical to the surface of the fiber. The length of the CNTs is typically controlled in 40 micron.
The growth of CNTs on the surface of carbon fiber or cloth(GDL) serves unique advantage as it supports the dispersion of noble metal nanoparticles (such as Pt catalyst for fuel cell application) in a three dimensional electrode structure thus providing higher catalyst utilization and more efficient mass transport.