Hydrogen and Fuel Cells

Summary

A significant research effort is being spent toward the use of hydrogen, mostly associated with Fuel Cells and to electrical motors (or also to internal combustion engines). By using hydrogen, instead of burning fossil fuels, CO2 production can be avoided. Hydrogen, however, is not a primary source of energy, but rather an energy storage medium, and must be manufactured using energy from other sources. Although its production does not necessarily reduce the dependance from fossil fuels, the advances of hydrogen-based technologies may represent an important contribution toward the diffusion of clean energy.

The History

Sir William Robert Grove (1811-1896) developed two electrochemical cells (batteries): the first cell consisted of zinc in dilute sulfuric acid and platinum in concentrated nitric acid, separated by a porous pot, that was practically used for the early American telegraph and the second cell, a "gas voltaic battery" was the forerunner of modern fuel cells. Thus, Grove is known as "Father of the Fuel Cell".

Sir William Robert Grove, the "Father of the Fuel Cell" (1811-1896).

William Grove produced the first fuel cell in 1839. He based his experiment on the fact that sending an electric current through water splits the water into its component parts of hydrogen and oxygen. So, Grove tried reversing the reaction - combining hydrogen and oxygen to produce electricity and water. This is the basis of a simple fuel cell. The term “fuel cell” was coined later in 1889 by Ludwig Mond and Charles Langer, who attempted to build the first practical device using air and industrial coal gas. Fuel cells got their start when William Grove immersed two platinum strips surrounded by closed tubes containing hydrogen and oxygen in an acidic electrolyte (see Grove's Device below). William Grove’s original fuel cell used dilute sulfuric acid because the reaction depends upon the pH when using an aqueous electrolyte.

The scheme of a fuel cell, published by Grove in one of the first accounts of an operating fuel cell (Philosophycal Magazine, 1839).

This first fuel cell became the prototype for the Phosphoric Acid Fuel Cell (PAFC), which has had a longer development period than the other fuel cell technologies. Unfortunately, he was hampered by the inconsistency of cell performance (a common feature of cells today), but realized the importance of the three phase contact (gas, electrolyte and platinum) to energy generation. He spent most of his time searching for an electrolyte that would produce a more constant current. He found several electrolytes which produced current, but still struggled with consistent results. He also noted the potential of the energy production method commercially if hydrogen could replace coal and wood as energy medium.

Hydrogen Availability

The major limitation of fuel cells today is due to the fact the hydrogen, despite its ubiquity in the universe, is difficult to obtain in large quantities and in economic way, and in most cases its production does not reduce the dependance from fossil fuels. In other words, hydrogen is not a primary source of energy: it is only an energy storage medium, and must be manufactured using energy from other sources. Further problems are associated with the on-board storage of hydrogen.

Due to these aspects, the extensive recourse to hydrogen and to Fuel-Cells can be considered as a long-term alternative to actual cars.

Link

http://chem.ch.huji.ac.il/~eugeniik/history/grove.htm
http://www.gmi.edu/~altfuel/fcback.htm

Top - Previous Module - Next Module