abbr. MCFCA high-temperature fuel cell, in the range of 600°C. Their main problem is corrosion, and the need to operate a high-temperature liquid rather than a solid as in the solid-oxide fuel cells. However, they operate at the highest efficiencies of any type fuel cell, including Solid-Oxide Fuel Cells (SOFC), Polymer Electrolyte Membrane Fuel Cells (PEMFC) and PAFC and are not subject to the high-temperature material issues that affect solid-oxide technology.