Editing Fuel cell (section)

===Alkaline fuel cell===
{{Main|Alkaline fuel cell|Alkaline anion exchange membrane fuel cell}}
The alkaline fuel cell (AFC) or hydrogen-oxygen fuel cell was designed and first demonstrated publicly by Francis Thomas Bacon in 1959. It was used as a primary source of electrical energy in the Apollo space program.<ref>{{Cite journal|title = Francis Thomas Bacon. 21 December 1904 – 24 May 1992|last = Williams|first = K.R.|s2cid = 71613260|date = 1 February 1994|journal = Biographical Memoirs of Fellows of the Royal Society|doi = 10.1098/rsbm.1994.0001|volume = 39|pages = 2–9|doi-access = free}}</ref> The cell consists of two porous carbon electrodes impregnated with a suitable catalyst such as Pt, Ag, CoO, etc. The space between the two electrodes is filled with a concentrated solution of [[Potassium hydroxide|KOH]] or [[Sodium hydroxide|NaOH]] which serves as an electrolyte. H<sub>2</sub> gas and O<sub>2</sub> gas are bubbled into the electrolyte through the porous carbon electrodes. Thus the overall reaction involves the combination of hydrogen gas and oxygen gas to form water. The cell runs continuously until the reactant's supply is exhausted. This type of cell operates efficiently in the temperature range 343–413{{nbsp}}K (70 -140&nbsp;°C) and provides a potential of about 0.9{{nbsp}}V.<ref>Srivastava, H. C. ''Nootan ISC Chemistry'' (12th) Edition 18, pp. 458–459, Nageen Prakashan (2014) {{ISBN|9789382319399}}</ref> [[Alkaline anion exchange membrane fuel cell]] (AAEMFC) is a type of AFC which employs a solid polymer electrolyte instead of aqueous potassium hydroxide (KOH) and it is superior to aqueous AFC.