In fuel cells, the electricity and heat are generated by electrochemical means. The central components are the anode, cathode and electrolyte membrane. In the cell, a hydrogen-rich gas is directed to a porous anode and oxygen is directed to a porous cathode. Both gases are separated from each other by the gas-impermeable membrane and thus prevented from producing a direct oxyhydrogen gas reaction. At the anode, free electrons and hydrogen ions are formed that penetrate the membrane. Here, the positive hydrogen ions meet the negative oxygen ions that have formed on the cathode. Both ions form under the application of heat to form water. The free electrons that formed on the anode side are conducted away via an external conductor and are used as useful electricity.
Membrane fuel cells (PEM-FC) work as low-temperature fuel cells with temperatures from 70 to 90 °C. They are intended for driving vehicles or for supplying energy to individual buildings. With temperatures between 900 and 1000 °C, high-temperature fuel cells (SOFC) have oxide-ceramic electrolytes for separating the gases. They are intended for use in power plants in local heating networks.
