Etymology and History of Electrolysis
- The term 'electrolysis' was introduced by Michael Faraday in 1834.
- The word is derived from the Greek words ἤλεκτρον and λύσις, meaning amber and dissolution, respectively.
- William Nicholson and Anthony Carlisle observed the production of hydrogen and oxygen through electrolysis in the early 19th century.
- Martin van Marum unknowingly produced electrolysis in 1785 while using an electrostatic generator to reduce tin, zinc, and antimony.
- Luigi Galvani's experiments with frog legs led to Alessandro Volta's tests on the generation of electricity through dissimilar metal sheets.
- Humphry Davy conducted preliminary experiments on electrolysis and hypothesised the release of electrical energy during the formation of compounds.
- Johan August Arfwedson discovered lithium in 1817, and William Thomas Brande used electrolysis to isolate it in 1821.

Overview and Process of Electrolysis
- Electrolysis involves the passing of a direct electric current through an electrolyte, resulting in chemical reactions and decomposition.
- The main components required for electrolysis are an electrolyte, electrodes, and an external power source.
- An ion-exchange membrane or salt bridge can be used as a partition to prevent diffusion of products.
- The electrolyte contains free ions and conducts electric current.
- Electrodes can be made of metal, graphite, or semiconductor materials, depending on reactivity and cost.
- Electrolysis involves the interchange of atoms and ions through the removal or addition of electrons.
- The desired products of electrolysis are often in a different physical state from the electrolyte and can be separated mechanically.
- The quantity of products is proportional to the applied current.
- Faraday's laws of electrolysis state that the products produced in electrolytic cells connected in series are proportional to their equivalent weight.
- Positively charged ions (cations) move towards the cathode, while negatively charged ions (anions) move towards the anode.

Variations and Applications of Electrolysis
- Pulsating current leads to different products compared to DC.
- Pulsing increases the ratio of ozone to oxygen produced in electrolysis of aqueous acidic solutions.
- Electrolysis of ethanol with pulsed current evolves an aldehyde instead of an acid.
- Galvanic cells and batteries use redox reactions to generate electrical potential.
- Secondary batteries can be considered as electrolytic cells when charged.
- Hall-Héroult process is used for producing aluminium.
- Electrometallurgy is used for producing various metals such as lithium, sodium, and potassium.
- Chloralkali process is used for producing chlorine and sodium hydroxide.
- Electrofluorination is used for producing perfluorinated organic compounds.
- Electrolysis is used for purifying copper, producing fuels like hydrogen, and removing rust.

Research Trends in Electrolysis
- Electrolysis of carbon dioxide can produce value-added chemicals such as methane, ethylene, and ethanol.
- Electrolysis of acidified water produces hydrogen and oxygen in a 2:1 ratio.
- Carbon/hydrocarbon assisted water electrolysis (CAWE) process utilizes carbon or hydrocarbon to reduce energy input in hydrogen generation.
- Electrocrystallization is a specialised application of electrolysis used to obtain conductive crystals.
- Electrolysis of iron ore can eliminate direct emissions in steel production if electricity is created from green energy.

Electrolysis of Seawater
- Direct electrolysis of seawater has been investigated as a method for hydrogen generation.
- Different electrolysis technologies, including alkaline electrolysis and proton-exchange membrane electrolysis, have been studied.
- Proton-exchange membrane electrolysis offers a suitable combination of economic operation costs, environmental considerations, and safety.
- Solid oxide electrolysers require high temperatures to operate but suffer from degradation when turned off.
- Multiple-criteria decision analysis has been used to evaluate the performance of different electrolysis methods.