MEMBRANE ELECTRODE ASSEMBLIES
At FuelCellsEtc, we are experts at creating custom Membrane Electrode Assemblies (MEAs) that will fit your electrochemical cell’s specifications. We are capable of creating just about any shape or size you may require. Our proprietary process supports rapid and accurate delivery of customized Membrane Electrode Assemblies and Catalyst Coated Membranes. Our experienced staff is able to satisfy a variety of requirements meeting some of the most stringent qualifications. We manufacture exact components according to any requirement we receive.
The Membrane Electrode Assembly (MEA) is the core component of a fuel cell and helps facilitate the electrochemical reactions needed to separate and recombine protons and electrons. On the anode, fuel is decomposed into its components. From there, protons diffuse through the membrane while electrons follow the electrical pathway and do work. The electrons and protons recombine on the cathode in the presence of the oxidant to form water. Catalysts on each side enable reactions, while the membrane allows protons to pass through while keeping the gases separate and preventing an electrical short.
A typical MEA is composed of a Polymer Electrolyte Membrane (PEM), two catalyst layers, and two Gas Diffusion Layers (GDL). A MEA with this configuration is known as a 5-Layer MEA due to its composition. An alternative version of a membrane electrode assembly is the 3-Layer MEA which is composed of a polymer electrolyte membrane with catalyst layers applied to both sides, anode and cathode. An alternative name for this type of MEA is a Catalyst Coated Membrane (CCM). The diagram shows the difference in the types of MEAs.
A few key differences in the types of Membrane Electrode Assemblies, 7-Layer, 5-Layer or 3 -Layer, are the presence of gasket material, a pre-selected GDL, and the location of the applied catalyst layers. In the 5-Layer MEAs, the GDL is a standard carbon cloth with a microporous layer (MPL) applied to one side of the GDL. The GDL is Teflon treated to assist in pushing the product water away from the catalyst sites, and the MPL is made of carbon powder and Teflon and applied to the cloth to give a smooth surface to apply the catalyst. The microporous layer is electrically conductive while maintaining an open pore structure to allow the gases into the reaction sites and removal of the product water. For 5-layer and 7-layer MEAs, the anode and cathode catalysts are usually applied to the selected GDL and then hot pressed on the desired membrane. This setup for easier catalyst application allows for quicker MEA fabrication.
The 3-Layer MEAs, also known as Catalyst Coated Membranes (CCMs), do not come with a GDL. This will allow you to experiment with different GDLs to find more optimal structures in your testing environment. The downside is that the catalyst must now be applied directly to the membrane which is a more difficult process. Both options will perform equally after the break-in period for the MEA, which is usually around 12 to 24 hours of operation. This operational period allows the product water to be distributed throughout the membrane and fully hydrate the MEA. 5-Layer MEAs are generally less expensive per MEA, whereas 7-Layer and 3-Layer MEAs have a higher cost, due to the increase in time and labor for manufacturing.