5. The fuel cell

5.1 Principle

In most technologies, the fuel cell achieves the reverse of water electrolysis. Hydrogen and oxygen from the air react within the fuel cell to produce electricity, heat and water. The principle was discovered in 1839 by Christian Schönbein, and the first prototype was built by the British Sir William Grove. Although the principle is simple, its realization is difficult. In the 1960s, NASA used fuel cells to produce electricity and water in the capsules of its...