William Grove

Grove's 1839 Grove cell battery and his 1842 fuel cell were significant steps in 19th-century electrochemistry. He also anticipated the idea of energy conservation, publishing 'On the Correlation of Physical Forces' in 1846, and later served as a judge of the High Court after returning to the legal profession in later life.

William's invention of the fuel cell arose from his fascination with the relationship between electricity and chemistry. In the late 1830s he had been experimenting with electrolysis, using electricity to split water into hydrogen and oxygen. He then asked a simple but profound question: if electricity could separate water into its constituent gases, could the process be reversed to generate electricity? In 1839 he demonstrated that it could.

He immersed platinum electrodes in separate containers of hydrogen and oxygen, with the gases separated by an electrolyte. Instead of applying electricity, the hydrogen and oxygen combined electrochemically on the platinum surfaces, producing an electric current while forming water as the only reaction product. Grove called his invention a "gas battery".

Although it generated only a modest amount of power and was far too expensive for practical use because it relied on platinum, it established the fundamental principle of the modern hydrogen fuel cell: converting the chemical energy of a fuel directly into electricity without combustion. More than a century later, advances in materials transformed Grove's elegant laboratory experiment into the fuel cells now used in spacecraft, backup power systems and hydrogen-powered vehicles.