There are different fuel cell technologies:
Alkaline fuel cells : used notably in the Apollo space missions, their operating temperature is limited to between 65°C and 90°C. They have been used in industry for over 100 years, and on a large scale. It can reach 250°C under pressure with a very concentrated electrolyte. Its efficiency is around 50%.
Proton exchange membrane fuel cells: these fuel cells operate at low temperatures (below 100°C) with a yield of around 50%. They have the ability to start up quickly, at full power, which makes it possible to supply energy to vehicles and small or medium-sized installations. PEMFC batteries can be found in power ranges from a few milliwatts to several hundred kilowatts.
Phosphoric acid fuel cells : PAFC technology is one of the most advanced in terms of development and marketing. It operates between 180°C and 210°C and can power stationary installations of several megawatts. The high heat released by the cell allows its use for cogeneration.
Molten carbonate fuel cells: Their operating temperatures are quite high, between 600°C and 700°C. They are used to operate large stationary energy productions (several tens of MW). They have a fairly high yield ranging from 60% to 80% depending on the application.
Solid oxide fuel cells: These cells operate at very high temperatures, between 800°C and 1000°C, which considerably improves the kinetic reactions. This avoids the need to use rare metal catalysts. However, the cells take longer to start up and the very high temperatures in the system require very good insulation and components that are very resistant to these temperatures. They are mainly used in stationary power generation.