Microbial Fuel Cell (MFC)

A Microbial Fuel Cell (MFC), or biological fuel cell, is a bio-electrochemical system that drives a current by mimicking bacterial interactions found in nature. MFCs can be grouped into two general categories, those that use a mediator and those that are mediator-less. The first MFCs, demonstrated in the early 20th century, used a mediator, a chemical that transfers electrons from the bacteria in the cell to the anode. Mediator-less MFCs are a more recent development dating to the 1970s; in this … [Read more...]

Solid Oxide Fuel Cell (SOFC)

Solid Oxide Fuel Cells (SOFC) use a hard, non-porous ceramic compound as its electrolyte. Because the electrolyte is a solid, the cells do not have to be constructed in the plate-like configuration typical of other fuel cell types. SOFCs are expected to be around 50%–60% efficient at converting fuel to electricity. In applications designed to capture and utilize the system's waste heat (co-generation), overall fuel use efficiencies could top 80%–85%. Solid oxide fuel cells operate at very … [Read more...]

Molten Carbonate Fuel Cell (MCFC)

Molten carbonate fuel cells (MCFC) are currently being developed for natural gas, biogas (produced as a result of anaerobic digestion or biomass gasification), and coal-based power plants for electrical utility, industrial, and military applications. MCFCs are high-temperature fuel cells, operating at temperatures of 600 °C and above, that use an electrolyte composed of a molten carbonate salt mixture suspended in a porous, chemically inert ceramic matrix of beta-alumina solid electrolyte … [Read more...]

Phosphoric Acid Fuel Cell (PAFC)

Phosphoric Acid Fuel Cells (PAFC) use liquid phosphoric acid as an electrolyte—the acid is contained in a Teflon-bonded silicon carbide matrix—and porous carbon electrodes containing a platinum catalyst. The PAFC is considered the "first generation" of modern fuel cells. It is one of the most mature cell types and the first to be used commercially. This type of fuel cell is typically used for stationary power generation, but some PAFCs have been used to power large vehicles such as city … [Read more...]

Alkaline Fuel Cell (AFC)

Alkaline fuel cells (AFC), also known as the Bacon fuel cell after its British inventor, were one of the first fuel cell technologies developed, and they were the first type widely used by NASA to produce electrical energy and water on-board spacecrafts. These fuel cells use a solution of potassium hydroxide in water as the electrolyte and can use a variety of non-precious metals as a catalyst at the anode and cathode. High-temperature AFCs operate at temperatures between 100°C and 250°C (212°F … [Read more...]

Direct Methanol Fuel Cell (DMFC)

Direct Methanol Fuel Cells (DMFC), a subcategory of proton-exchange fuel cells, are powered by pure methanol, which is mixed with steam and fed directly to the fuel cell anode. Their main advantage is the ease of transport of methanol, an energy-dense yet reasonably stable liquid at all environmental conditions. Efficiency is low for these cells, so they are targeted especially to portable applications, where energy and power density are more important than efficiency. … [Read more...]

Polymer Electrolyte Membrane (PEM) Fuel Cell

Polymer Electrolyte Membrane (PEM) Fuel Cells (PEMFC), also known as proton exchange membrane fuel cells, deliver high-power density and offer the advantages of low weight and volume, compared with other fuel cells. Their distinguishing features include lower temperature/pressure ranges (50 to 100 °C), a solid polymer electrolyte membrane and porous carbon electrodes containing a platinum catalyst. PEM fuel cells need hydrogen, oxygen from the air, and water to operate and do not require … [Read more...]