
A substance containing ions that conducts electricity, used here as the working fluid in the experiment.An electrolyte is a substance that contains free ions and conducts electricity through their movement. In the context of the cited experiments, it is the working fluid — typically a salt dissolved in water or another solvent — that enables the flow of charge between electrodes. Electrolytes are central to electrochemistry: they are the medium in which chemical reactions at electrodes are balanced by ionic transport, enabling batteries, fuel cells, and electrolyzers to function.
The term 'electrolyte' was coined by Michael Faraday in the 1830s, who also introduced the terms 'electrode', 'anode', and 'cathode' based on his experiments on electrolysis.
When an electric field is applied, positive ions (cations) migrate toward the negative electrode and negative ions (anions) toward the positive electrode. This ionic motion constitutes the electric current. The conductivity of an electrolyte depends on the concentration and mobility of the ions, which in turn depend on the solvent's viscosity, temperature, and the ion's size and charge. In water, ions are often surrounded by a hydration shell that affects their movement and interactions.
Electrolytes are used in all electrochemical devices: lithium-ion batteries, fuel cells, electrolyzers for hydrogen production, and supercapacitors. They are also essential in biological systems, where they maintain nerve and muscle function.
In some electrolytes, ions of the same charge can attract each other due to the structured arrangement of water molecules around them, a counterintuitive effect that has been observed in recent experiments.








