Electrolysis Definition in Chemistry

Chemistry Glossary Definition of Electrolysis

Illustration of an electrolysis apparatus used in a school laboratory
Ivan Akira/Wikimedia Commons/CC BY-SA 3.0

Electrolysis is the passage of a direct electric current through an ion-containing solution to drive a non-spontaneous chemical reaction. Electrolysis produces chemical changes at the electrodes.

Uses of Electrolysis

On an industrial scale, electrolysis is used to purify metals, including aluminum, lithium, potassium, magnesium, and sodium. It is used to produce chlorine, sodium chlorate, sodium hydroxide, and potassium chlorate. In the energy industry, it's used to make hydrogen for fuel. In the aerospace industry, it's used to produce oxygen for spacecraft. Oxygen for submarines is also isolated using electrolysis.

In addition to chemical synthesis and purification, electrolysis is used to electroplate metal over a surface and for electrochemical machining to etch or clean a surface.


  • Ju, Hyungkuk; Badwal, Sukhvinder; Giddey, Sarbjit (2018). "A comprehensive review of carbon and hydrocarbon assisted water electrolysis for hydrogen production". Applied Energy. 231: 502–533. doi:10.1016/j.apenergy.2018.09.125
  • Tilley, R.J.D. (2004). Understanding Solids: The Science of Materials. John Wiley and Sons. ISBN 978-0-470-85276-7.