For transportation, two types of fuel cells come to mind: PEMs or SOFCs. A third variety, DCFCs, may have a place in transport systems, and may have advantages in using “dirty” fuels. PEM (Polymer Electrolyte Membrane – or Proton Exchange Membrane) cells use a solid polymer as an electrolyte and porous carbon electrodes containing a platinum or platinum alloy catalyst. They need only hydrogen, oxygen from the air, and water to operate. They are typically fueled with pure hydrogen supplied from storage tanks or reformers. SOFCs (Solid Oxide Fuel Cells) use a hard, non-porous ceramic compound as the electrolyte. SOFCs are around 60% efficient at converting fuel to electricity. In applications designed to capture and utilize the system’s waste heat …
