The Heart of Fuel Cells, “MEAs,” May Propel the Future of Green Energy
AAC spoke to Gore to learn how membrane electrode assemblies in fuel cells can help decarbonize applications from drones to warehouses.
While fuel cells have been around for almost a century, over the past decade their development has rapidly increased because of their potential to produce sustainable energy.
Fuel cells are designed to convert the chemical energy of hydrogen and oxygen into electrical energy. The cell itself consists of an anode and cathode, sandwiched around an electrolyte—a liquid or gel containing ions (also contained in batteries).
Depiction of how fuel cells work. Image used courtesy of the Fuel Cell & Hydrogen Energy Association
W. L. Gore & Associates, a global materials science company with its U.S. headquarters based in Newark, Delaware, produces items derived from fluoropolymers. Gore is also one of the leading suppliers of membrane electrode assemblies (MEAs), the core component that helps to initiate the electrochemical reaction required to separate electrons in fuel cells.
The MEAs produced by Gore is currently integrated into over 80% of fuel cell technologies on the market. We spoke to Simon Cleghorn, who has been an associate at Gore for the past 23 years, to better understand how Gore’s MEAs work and how they may help produce cleaner energy.
Gore's Specialty: PTFE-based Fuel Cell Components
Most of the products developed by Gore are based on polytetrafluoroethylene (PTFE), a synthetic material that can be used to make valves, seals, lab and medical equipment, weatherproof jackets, and more. PTFE can also be used to fabricate MEAs for fuel cells.
“Gore produces two main fuel cell components,” Cleghorn said. “One is the membrane, which is an ePTFE [expanded polytetraethylene] micro-reinforced fuel cell membrane. The other is membrane electrode assembly, which entails attaching electrodes to each side of the membrane.”
Hydrogen fuel cell membranes developed by Gore. Image used courtesy of Gore
Hydrogen fuel cells are essentially engines. Inside, hydrogen reacts with oxygen contained on either side of an MEA to produce an electrical current. This current can then be used to drive electric motors.
What are Membrane Electrode Assemblies?
Membrane electrode assemblies (MEAs), the main components produced by Gore, are the heart of a fuel cell. Within fuel cells, MEAs are where oxygen is reduced and water is generated. These essential fuel cell parts consist of a polymer electrolyte membrane (PEM) at the center, sandwiched between two catalyst layers and gas diffusion layers.
“The anode oxidizes the hydrogen fuel into a proton,” Cleghorn explained. “The proton is transported through the membrane and then it reacts on the cathode electrode of the MEA to form water. Finally, the electrons pass through the external circuit to generate electrical current.”
The most important part of MEAs are membranes, which are electrical insulators that separate the hydrogen from the oxygen and allow protons to pass through. This membrane forces electrons to pass through the MEA's external circuit, where they can then be used to power devices.
Gore specializes in PEM design modeling. Image used courtesy of Gore
“Gore has become a leader in this industry due to our ability to make membranes that are thinner and stronger than those produced by anyone else in the industry,” Cleghorn said. “This is possible due to our core technology at Gore, which is ePTFE, or expanded polytetraethylene.”
ePTFE is a strong polymer material with a high porosity, which allows protons to pass through it quickly. These properties yield fuel cells with low resistance and high power, which can operate for long lifetimes in harsh environments.
“A long lifetime is important, especially in mobility applications where high power allows you to produce smaller engines and to reduce some of the complexity around the system,” Cleghorn said. “In fuel cells, high power means more heat generation, which in our case it means that we may need a larger radiator.”
Fuel Cells Power Houses, Warehouses, Cars, and More
Currently, fuel cells are primarily used to power forklift trucks; approximately tens of thousands of forklifts now rely on fuel cell technology. In Japan and a few other countries worldwide, fuel cells are sometimes also used to provide electricity and heating to residential homes or other buildings.
“Two of the largest users of fuel cells today are Walmart and Amazon, who have converted a lot of their warehouse operation to use fuel cells. They have decarbonized their warehouses and replaced battery forklifts with fuel cells,” Cleghorn said. “This gives them much longer run times, reducing costs and increasing efficiency in warehouses.”
While so far these are the primary real-world applications of fuel cells, some companies have also started testing their effectiveness in other settings. For instance, Toyota and Hyundai have tried to use fuel cells to power cars and other motor vehicles.
Fuel-cell EVs. Image used courtesy of Gore
Fuel cells may also be used to reduce diesel production, powering heavy-duty trucks, trains, ferries, large ships, drones, or aircraft that cannot be effectively powered by lithium batteries with lower energy densities.
“Because the fuel is not generally available everywhere in the world and the fueling infrastructure is still being built, there are limited fuel cell-powered vehicles on the road today,” Cleghorn said. “There are now trains running in Germany with fuel cells replacing diesel, but this is still more of a demonstration. Installing overhead electrical lines electrification is really expensive.”
Hydrogen as the Next-generation Fossil Fuel
Several infrastructural changes are necessary before fuel cells can be implemented on a larger scale. In fact, fuel cell operation relies on support from several other peripheral systems, including devices for power conditioning, fuel delivery systems, and air delivery systems.
Nonetheless, fuel cell technology may meaningfully contribute to worldwide decarbonization efforts, since they substitute fossil fuels with hydrogen. Because fuel cells are not the only sustainable energy solution that relies on the use of hydrogen, they may eventually become a key part of a new hydrogen-based energy ecosystem.
The switch to hydrogen is an infrastructural effort. Image used courtesy of Gore
“Clean hydrogen is a great energy carrier, so just like a fossil fuel, you can put it in a tank and refuel,” Cleghorn said. “The advantage of hydrogen is that when you utilize it, your byproduct is water, so you're not really using any carbon dioxide. Currently, there's a lot of work now going on in Europe to take renewables, such as wind and solar energy, through electrolyzers to make green hydrogen. Then that hydrogen could be used in all of these different fuel cell applications or also using green hydrogen in chemical processes.”
Today, as the war in Ukraine continues, many countries in Europe are eager to reduce their reliance on Russian oil and gas, which further motivates them to explore alternative energy solutions. In the near future, Gore’s fuel cell components may play an increasingly crucial role in the global shift toward a greener energy infrastructure.
“I see fuel cells and hydrogen playing a greater and greater part in our future world,” Cleghorn added. “I also see both batteries and fuel cells as important solutions, which will not necessarily be competing, but rather working together to decarbonize numerous real-world applications.”